diff --git a/pants.toml b/pants.toml
index f29cee3f383..608db4a4aa0 100644
--- a/pants.toml
+++ b/pants.toml
@@ -86,6 +86,8 @@ pants_ignore.add = [
   "/build-support/*.venv/",
   # An absolute symlink to the Pants Rust toolchain sources.
   "/build-support/bin/native/src",
+  # We shouldn't walk or watch the rust compiler artifacts because it is slow.
+  "/src/rust/engine/target",
 ]
 
 [cache]
diff --git a/src/rust/engine/Cargo.lock b/src/rust/engine/Cargo.lock
index 3c20be1caa5..49ac0dd8fdc 100644
--- a/src/rust/engine/Cargo.lock
+++ b/src/rust/engine/Cargo.lock
@@ -7,10 +7,10 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
 name = "aho-corasick"
-version = "0.7.8"
+version = "0.7.10"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "memchr 2.3.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "memchr 2.3.3 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -22,13 +22,13 @@ dependencies = [
 ]
 
 [[package]]
-name = "anyhow"
-version = "1.0.26"
+name = "anymap"
+version = "0.12.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
 name = "arc-swap"
-version = "0.4.4"
+version = "0.4.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
@@ -43,12 +43,12 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
 name = "async-trait"
-version = "0.1.24"
+version = "0.1.26"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "proc-macro2 1.0.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "quote 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 1.0.14 (registry+https://github.com/rust-lang/crates.io-index)",
+ "proc-macro2 1.0.9 (registry+https://github.com/rust-lang/crates.io-index)",
+ "quote 1.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 1.0.16 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -66,8 +66,8 @@ name = "atty"
 version = "0.2.14"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "hermit-abi 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.66 (registry+https://github.com/rust-lang/crates.io-index)",
+ "hermit-abi 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.68 (registry+https://github.com/rust-lang/crates.io-index)",
  "winapi 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -83,22 +83,22 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
 name = "backtrace"
-version = "0.3.44"
+version = "0.3.45"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "backtrace-sys 0.1.32 (registry+https://github.com/rust-lang/crates.io-index)",
+ "backtrace-sys 0.1.34 (registry+https://github.com/rust-lang/crates.io-index)",
  "cfg-if 0.1.10 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.66 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.68 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc-demangle 0.1.16 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
 name = "backtrace-sys"
-version = "0.1.32"
+version = "0.1.34"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "cc 1.0.50 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.66 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.68 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -135,7 +135,7 @@ version = "1.2.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "byteorder 1.3.4 (registry+https://github.com/rust-lang/crates.io-index)",
- "serde 1.0.104 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde 1.0.105 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -193,7 +193,7 @@ dependencies = [
  "futures 0.1.29 (registry+https://github.com/rust-lang/crates.io-index)",
  "futures 0.3.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "hashing 0.0.1",
- "libc 0.2.66 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.68 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "parking_lot 0.6.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "protobuf 2.0.6 (git+https://github.com/pantsbuild/rust-protobuf?rev=171611c33ec92f07e1b7107327f6d0139a7afebf)",
@@ -209,10 +209,10 @@ dependencies = [
 
 [[package]]
 name = "bstr"
-version = "0.2.11"
+version = "0.2.12"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "memchr 2.3.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "memchr 2.3.3 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -253,14 +253,6 @@ name = "bytesize"
 version = "1.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
-[[package]]
-name = "c2-chacha"
-version = "0.2.3"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-dependencies = [
- "ppv-lite86 0.2.6 (registry+https://github.com/rust-lang/crates.io-index)",
-]
-
 [[package]]
 name = "cargo"
 version = "0.34.0"
@@ -274,12 +266,12 @@ dependencies = [
  "crates-io 0.22.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "crossbeam-utils 0.6.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "crypto-hash 0.3.4 (registry+https://github.com/rust-lang/crates.io-index)",
- "curl 0.4.25 (registry+https://github.com/rust-lang/crates.io-index)",
- "curl-sys 0.4.25 (registry+https://github.com/rust-lang/crates.io-index)",
+ "curl 0.4.28 (registry+https://github.com/rust-lang/crates.io-index)",
+ "curl-sys 0.4.30+curl-7.69.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "env_logger 0.6.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "failure 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
+ "failure 0.1.7 (registry+https://github.com/rust-lang/crates.io-index)",
  "filetime 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "flate2 1.0.13 (registry+https://github.com/rust-lang/crates.io-index)",
+ "flate2 1.0.14 (registry+https://github.com/rust-lang/crates.io-index)",
  "fs2 0.4.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "fwdansi 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "git2 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -287,12 +279,12 @@ dependencies = [
  "glob 0.2.11 (registry+https://github.com/rust-lang/crates.io-index)",
  "hex 0.3.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "home 0.3.4 (registry+https://github.com/rust-lang/crates.io-index)",
- "ignore 0.4.11 (registry+https://github.com/rust-lang/crates.io-index)",
+ "ignore 0.4.12 (registry+https://github.com/rust-lang/crates.io-index)",
  "im-rc 12.3.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "jobserver 0.1.21 (registry+https://github.com/rust-lang/crates.io-index)",
  "lazy_static 1.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "lazycell 1.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.66 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.68 (registry+https://github.com/rust-lang/crates.io-index)",
  "libgit2-sys 0.7.11 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "miow 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -302,7 +294,7 @@ dependencies = [
  "rustfix 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "same-file 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "semver 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "serde 1.0.104 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde 1.0.105 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde_ignored 0.0.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde_json 1.0.48 (registry+https://github.com/rust-lang/crates.io-index)",
  "shell-escape 0.1.4 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -325,8 +317,8 @@ dependencies = [
  "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "proc-macro2 0.4.30 (registry+https://github.com/rust-lang/crates.io-index)",
  "quote 0.6.13 (registry+https://github.com/rust-lang/crates.io-index)",
- "serde 1.0.104 (registry+https://github.com/rust-lang/crates.io-index)",
- "serde_derive 1.0.104 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde 1.0.105 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde_derive 1.0.105 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde_json 1.0.48 (registry+https://github.com/rust-lang/crates.io-index)",
  "syn 0.15.44 (registry+https://github.com/rust-lang/crates.io-index)",
  "tempfile 3.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -343,9 +335,18 @@ name = "cfg-if"
 version = "0.1.10"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
+[[package]]
+name = "chashmap"
+version = "2.2.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "owning_ref 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parking_lot 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "chrono"
-version = "0.4.10"
+version = "0.4.11"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "num-integer 0.1.42 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -404,7 +405,7 @@ name = "commoncrypto-sys"
 version = "0.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "libc 0.2.66 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.68 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -412,8 +413,8 @@ name = "concrete_time"
 version = "0.0.1"
 dependencies = [
  "protobuf 2.0.6 (git+https://github.com/pantsbuild/rust-protobuf?rev=171611c33ec92f07e1b7107327f6d0139a7afebf)",
- "serde 1.0.104 (registry+https://github.com/rust-lang/crates.io-index)",
- "serde_derive 1.0.104 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde 1.0.105 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde_derive 1.0.105 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -435,7 +436,7 @@ version = "0.6.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "core-foundation-sys 0.6.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.66 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.68 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -444,7 +445,7 @@ version = "0.7.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "core-foundation-sys 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.66 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.68 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -462,10 +463,10 @@ name = "crates-io"
 version = "0.22.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "curl 0.4.25 (registry+https://github.com/rust-lang/crates.io-index)",
- "failure 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
- "serde 1.0.104 (registry+https://github.com/rust-lang/crates.io-index)",
- "serde_derive 1.0.104 (registry+https://github.com/rust-lang/crates.io-index)",
+ "curl 0.4.28 (registry+https://github.com/rust-lang/crates.io-index)",
+ "failure 0.1.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde 1.0.105 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde_derive 1.0.105 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde_json 1.0.48 (registry+https://github.com/rust-lang/crates.io-index)",
  "url 1.7.2 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
@@ -480,10 +481,19 @@ dependencies = [
 
 [[package]]
 name = "crossbeam-channel"
-version = "0.4.0"
+version = "0.3.9"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "crossbeam-utils 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "crossbeam-utils 0.6.6 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "crossbeam-channel"
+version = "0.4.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "crossbeam-utils 0.7.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "maybe-uninit 2.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -497,10 +507,10 @@ dependencies = [
 
 [[package]]
 name = "crossbeam-utils"
-version = "0.7.0"
+version = "0.7.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "autocfg 0.1.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "autocfg 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "cfg-if 0.1.10 (registry+https://github.com/rust-lang/crates.io-index)",
  "lazy_static 1.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
@@ -526,11 +536,11 @@ dependencies = [
 
 [[package]]
 name = "curl"
-version = "0.4.25"
+version = "0.4.28"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "curl-sys 0.4.25 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.66 (registry+https://github.com/rust-lang/crates.io-index)",
+ "curl-sys 0.4.30+curl-7.69.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.68 (registry+https://github.com/rust-lang/crates.io-index)",
  "openssl-probe 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "openssl-sys 0.9.54 (registry+https://github.com/rust-lang/crates.io-index)",
  "schannel 0.1.17 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -540,12 +550,12 @@ dependencies = [
 
 [[package]]
 name = "curl-sys"
-version = "0.4.25"
+version = "0.4.30+curl-7.69.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "cc 1.0.50 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.66 (registry+https://github.com/rust-lang/crates.io-index)",
- "libnghttp2-sys 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.68 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libnghttp2-sys 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "libz-sys 1.0.25 (registry+https://github.com/rust-lang/crates.io-index)",
  "openssl-sys 0.9.54 (registry+https://github.com/rust-lang/crates.io-index)",
  "pkg-config 0.3.17 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -555,7 +565,7 @@ dependencies = [
 
 [[package]]
 name = "derivative"
-version = "1.0.3"
+version = "1.0.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "proc-macro2 0.4.30 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -568,9 +578,9 @@ name = "derivative"
 version = "2.0.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "proc-macro2 1.0.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "quote 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 1.0.14 (registry+https://github.com/rust-lang/crates.io-index)",
+ "proc-macro2 1.0.9 (registry+https://github.com/rust-lang/crates.io-index)",
+ "quote 1.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 1.0.16 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -594,7 +604,7 @@ name = "dirs"
 version = "1.0.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "libc 0.2.66 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.68 (registry+https://github.com/rust-lang/crates.io-index)",
  "redox_users 0.3.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "winapi 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
@@ -614,7 +624,7 @@ version = "0.3.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "cfg-if 0.1.10 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.66 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.68 (registry+https://github.com/rust-lang/crates.io-index)",
  "redox_users 0.3.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "winapi 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
@@ -641,14 +651,18 @@ dependencies = [
 name = "engine"
 version = "0.0.1"
 dependencies = [
- "async-trait 0.1.24 (registry+https://github.com/rust-lang/crates.io-index)",
+ "async-trait 0.1.26 (registry+https://github.com/rust-lang/crates.io-index)",
+ "async_semaphore 0.0.1",
  "boxfuture 0.0.1",
  "bytes 0.4.12 (registry+https://github.com/rust-lang/crates.io-index)",
  "concrete_time 0.0.1",
+ "crossbeam-channel 0.3.9 (registry+https://github.com/rust-lang/crates.io-index)",
+ "env_logger 0.5.13 (registry+https://github.com/rust-lang/crates.io-index)",
  "fnv 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "fs 0.0.1",
  "futures 0.1.29 (registry+https://github.com/rust-lang/crates.io-index)",
  "futures 0.3.4 (registry+https://github.com/rust-lang/crates.io-index)",
+ "futures-locks 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "graph 0.0.1",
  "hashing 0.0.1",
  "indexmap 1.3.2 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -656,6 +670,7 @@ dependencies = [
  "lazy_static 1.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "logging 0.0.1",
+ "notify 5.0.0-pre.1 (git+https://github.com/notify-rs/notify?rev=fba00891d9105e2f581c69fbe415a58cb7966fdd)",
  "num_cpus 1.12.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "num_enum 0.4.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "parking_lot 0.6.4 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -668,6 +683,7 @@ dependencies = [
  "store 0.1.0",
  "task_executor 0.0.1",
  "tempfile 3.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "testutil 0.0.1",
  "time 0.1.42 (registry+https://github.com/rust-lang/crates.io-index)",
  "tokio 0.2.13 (registry+https://github.com/rust-lang/crates.io-index)",
  "ui 0.0.1",
@@ -705,7 +721,7 @@ dependencies = [
  "atty 0.2.14 (registry+https://github.com/rust-lang/crates.io-index)",
  "humantime 1.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "regex 1.3.4 (registry+https://github.com/rust-lang/crates.io-index)",
+ "regex 1.3.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "termcolor 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -717,7 +733,7 @@ dependencies = [
  "atty 0.2.14 (registry+https://github.com/rust-lang/crates.io-index)",
  "humantime 1.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "regex 1.3.4 (registry+https://github.com/rust-lang/crates.io-index)",
+ "regex 1.3.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "termcolor 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -727,7 +743,7 @@ version = "0.2.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "errno-dragonfly 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.66 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.68 (registry+https://github.com/rust-lang/crates.io-index)",
  "winapi 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -737,26 +753,26 @@ version = "0.1.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "gcc 0.3.55 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.66 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.68 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
 name = "failure"
-version = "0.1.6"
+version = "0.1.7"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "backtrace 0.3.44 (registry+https://github.com/rust-lang/crates.io-index)",
- "failure_derive 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
+ "backtrace 0.3.45 (registry+https://github.com/rust-lang/crates.io-index)",
+ "failure_derive 0.1.7 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
 name = "failure_derive"
-version = "0.1.6"
+version = "0.1.7"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "proc-macro2 1.0.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "quote 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 1.0.14 (registry+https://github.com/rust-lang/crates.io-index)",
+ "proc-macro2 1.0.9 (registry+https://github.com/rust-lang/crates.io-index)",
+ "quote 1.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 1.0.16 (registry+https://github.com/rust-lang/crates.io-index)",
  "synstructure 0.12.3 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -771,7 +787,7 @@ version = "0.2.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "cfg-if 0.1.10 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.66 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.68 (registry+https://github.com/rust-lang/crates.io-index)",
  "redox_syscall 0.1.56 (registry+https://github.com/rust-lang/crates.io-index)",
  "winapi 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
@@ -783,12 +799,12 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
 name = "flate2"
-version = "1.0.13"
+version = "1.0.14"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "cfg-if 0.1.10 (registry+https://github.com/rust-lang/crates.io-index)",
  "crc32fast 1.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.66 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.68 (registry+https://github.com/rust-lang/crates.io-index)",
  "libz-sys 1.0.25 (registry+https://github.com/rust-lang/crates.io-index)",
  "miniz_oxide 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
@@ -815,11 +831,11 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 name = "fs"
 version = "0.0.1"
 dependencies = [
- "async-trait 0.1.24 (registry+https://github.com/rust-lang/crates.io-index)",
+ "async-trait 0.1.26 (registry+https://github.com/rust-lang/crates.io-index)",
  "bytes 0.4.12 (registry+https://github.com/rust-lang/crates.io-index)",
  "futures 0.3.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "glob 0.2.11 (registry+https://github.com/rust-lang/crates.io-index)",
- "ignore 0.4.11 (registry+https://github.com/rust-lang/crates.io-index)",
+ "ignore 0.4.12 (registry+https://github.com/rust-lang/crates.io-index)",
  "lazy_static 1.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "parking_lot 0.6.4 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -834,7 +850,7 @@ name = "fs2"
 version = "0.4.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "libc 0.2.66 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.68 (registry+https://github.com/rust-lang/crates.io-index)",
  "winapi 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -853,8 +869,8 @@ dependencies = [
  "parking_lot 0.6.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "protobuf 2.0.6 (git+https://github.com/pantsbuild/rust-protobuf?rev=171611c33ec92f07e1b7107327f6d0139a7afebf)",
  "rand 0.6.5 (registry+https://github.com/rust-lang/crates.io-index)",
- "serde 1.0.104 (registry+https://github.com/rust-lang/crates.io-index)",
- "serde_derive 1.0.104 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde 1.0.105 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde_derive 1.0.105 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde_json 1.0.48 (registry+https://github.com/rust-lang/crates.io-index)",
  "store 0.1.0",
  "task_executor 0.0.1",
@@ -862,6 +878,23 @@ dependencies = [
  "workunit_store 0.0.1",
 ]
 
+[[package]]
+name = "fsevent"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "bitflags 1.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "fsevent-sys 2.0.1 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "fsevent-sys"
+version = "2.0.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "libc 0.2.68 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "fuchsia-cprng"
 version = "0.1.1"
@@ -886,7 +919,7 @@ name = "fuse"
 version = "0.3.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "libc 0.2.66 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.68 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.3.9 (registry+https://github.com/rust-lang/crates.io-index)",
  "pkg-config 0.3.17 (registry+https://github.com/rust-lang/crates.io-index)",
  "thread-scoped 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -941,15 +974,25 @@ name = "futures-io"
 version = "0.3.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
+[[package]]
+name = "futures-locks"
+version = "0.3.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "futures 0.1.29 (registry+https://github.com/rust-lang/crates.io-index)",
+ "tokio-current-thread 0.1.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "tokio-executor 0.1.10 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "futures-macro"
 version = "0.3.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "proc-macro-hack 0.5.11 (registry+https://github.com/rust-lang/crates.io-index)",
- "proc-macro2 1.0.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "quote 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 1.0.14 (registry+https://github.com/rust-lang/crates.io-index)",
+ "proc-macro-hack 0.5.12 (registry+https://github.com/rust-lang/crates.io-index)",
+ "proc-macro2 1.0.9 (registry+https://github.com/rust-lang/crates.io-index)",
+ "quote 1.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 1.0.16 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -974,10 +1017,10 @@ dependencies = [
  "futures-macro 0.3.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "futures-sink 0.3.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "futures-task 0.3.4 (registry+https://github.com/rust-lang/crates.io-index)",
- "memchr 2.3.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "memchr 2.3.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "pin-utils 0.1.0-alpha.4 (registry+https://github.com/rust-lang/crates.io-index)",
- "proc-macro-hack 0.5.11 (registry+https://github.com/rust-lang/crates.io-index)",
- "proc-macro-nested 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "proc-macro-hack 0.5.12 (registry+https://github.com/rust-lang/crates.io-index)",
+ "proc-macro-nested 0.1.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "slab 0.4.2 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -986,7 +1029,7 @@ name = "fwdansi"
 version = "1.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "memchr 2.3.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "memchr 2.3.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "termcolor 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -1009,7 +1052,7 @@ version = "0.1.14"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "cfg-if 0.1.10 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.66 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.68 (registry+https://github.com/rust-lang/crates.io-index)",
  "wasi 0.9.0+wasi-snapshot-preview1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -1019,7 +1062,7 @@ version = "0.8.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "bitflags 1.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.66 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.68 (registry+https://github.com/rust-lang/crates.io-index)",
  "libgit2-sys 0.7.11 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "openssl-probe 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -1032,7 +1075,7 @@ name = "git2-curl"
 version = "0.9.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "curl 0.4.25 (registry+https://github.com/rust-lang/crates.io-index)",
+ "curl 0.4.28 (registry+https://github.com/rust-lang/crates.io-index)",
  "git2 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "url 1.7.2 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -1045,14 +1088,14 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
 name = "globset"
-version = "0.4.4"
+version = "0.4.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "aho-corasick 0.7.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "bstr 0.2.11 (registry+https://github.com/rust-lang/crates.io-index)",
+ "aho-corasick 0.7.10 (registry+https://github.com/rust-lang/crates.io-index)",
+ "bstr 0.2.12 (registry+https://github.com/rust-lang/crates.io-index)",
  "fnv 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "regex 1.3.4 (registry+https://github.com/rust-lang/crates.io-index)",
+ "regex 1.3.5 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -1077,7 +1120,7 @@ source = "git+https://github.com/pantsbuild/grpc-rs.git?rev=b582ef3dc4e8c7289093
 dependencies = [
  "futures 0.1.29 (registry+https://github.com/rust-lang/crates.io-index)",
  "grpcio-sys 0.2.3 (git+https://github.com/pantsbuild/grpc-rs.git?rev=b582ef3dc4e8c7289093c8febff8dadf0997b532)",
- "libc 0.2.66 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.68 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "protobuf 2.0.6 (git+https://github.com/pantsbuild/rust-protobuf?rev=171611c33ec92f07e1b7107327f6d0139a7afebf)",
 ]
@@ -1098,7 +1141,7 @@ source = "git+https://github.com/pantsbuild/grpc-rs.git?rev=b582ef3dc4e8c7289093
 dependencies = [
  "cc 1.0.50 (registry+https://github.com/rust-lang/crates.io-index)",
  "cmake 0.1.42 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.66 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.68 (registry+https://github.com/rust-lang/crates.io-index)",
  "pkg-config 0.3.17 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -1143,9 +1186,9 @@ version = "0.0.1"
 dependencies = [
  "digest 0.8.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "hex 0.3.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "serde 1.0.104 (registry+https://github.com/rust-lang/crates.io-index)",
- "serde_derive 1.0.104 (registry+https://github.com/rust-lang/crates.io-index)",
- "serde_test 1.0.104 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde 1.0.105 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde_derive 1.0.105 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde_test 1.0.105 (registry+https://github.com/rust-lang/crates.io-index)",
  "sha2 0.8.1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -1159,10 +1202,10 @@ dependencies = [
 
 [[package]]
 name = "hermit-abi"
-version = "0.1.6"
+version = "0.1.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "libc 0.2.66 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.68 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -1283,15 +1326,16 @@ dependencies = [
 
 [[package]]
 name = "ignore"
-version = "0.4.11"
+version = "0.4.12"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "crossbeam-channel 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "globset 0.4.4 (registry+https://github.com/rust-lang/crates.io-index)",
+ "crossbeam-channel 0.4.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "crossbeam-utils 0.7.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "globset 0.4.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "lazy_static 1.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "memchr 2.3.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "regex 1.3.4 (registry+https://github.com/rust-lang/crates.io-index)",
+ "memchr 2.3.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "regex 1.3.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "same-file 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "thread_local 1.0.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "walkdir 2.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -1316,12 +1360,30 @@ dependencies = [
  "autocfg 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "inotify"
+version = "0.7.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "bitflags 1.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "inotify-sys 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.68 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "inotify-sys"
+version = "0.1.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "libc 0.2.68 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "iovec"
 version = "0.1.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "libc 0.2.66 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.68 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -1350,15 +1412,15 @@ name = "jobserver"
 version = "0.1.21"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "libc 0.2.66 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.68 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
 name = "js-sys"
-version = "0.3.35"
+version = "0.3.36"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "wasm-bindgen 0.2.58 (registry+https://github.com/rust-lang/crates.io-index)",
+ "wasm-bindgen 0.2.59 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -1382,7 +1444,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
 name = "libc"
-version = "0.2.66"
+version = "0.2.68"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
@@ -1391,9 +1453,9 @@ version = "0.7.11"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "cc 1.0.50 (registry+https://github.com/rust-lang/crates.io-index)",
- "curl-sys 0.4.25 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.66 (registry+https://github.com/rust-lang/crates.io-index)",
- "libssh2-sys 0.2.14 (registry+https://github.com/rust-lang/crates.io-index)",
+ "curl-sys 0.4.30+curl-7.69.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.68 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libssh2-sys 0.2.16 (registry+https://github.com/rust-lang/crates.io-index)",
  "libz-sys 1.0.25 (registry+https://github.com/rust-lang/crates.io-index)",
  "openssl-sys 0.9.54 (registry+https://github.com/rust-lang/crates.io-index)",
  "pkg-config 0.3.17 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -1401,20 +1463,20 @@ dependencies = [
 
 [[package]]
 name = "libnghttp2-sys"
-version = "0.1.2"
+version = "0.1.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "cc 1.0.50 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.66 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.68 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
 name = "libssh2-sys"
-version = "0.2.14"
+version = "0.2.16"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "cc 1.0.50 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.66 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.68 (registry+https://github.com/rust-lang/crates.io-index)",
  "libz-sys 1.0.25 (registry+https://github.com/rust-lang/crates.io-index)",
  "openssl-sys 0.9.54 (registry+https://github.com/rust-lang/crates.io-index)",
  "pkg-config 0.3.17 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -1427,7 +1489,7 @@ version = "1.0.25"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "cc 1.0.50 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.66 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.68 (registry+https://github.com/rust-lang/crates.io-index)",
  "pkg-config 0.3.17 (registry+https://github.com/rust-lang/crates.io-index)",
  "vcpkg 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
@@ -1438,7 +1500,7 @@ version = "0.8.0"
 source = "git+https://github.com/pantsbuild/lmdb-rs.git?rev=06bdfbfc6348f6804127176e561843f214fc17f8#06bdfbfc6348f6804127176e561843f214fc17f8"
 dependencies = [
  "bitflags 1.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.66 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.68 (registry+https://github.com/rust-lang/crates.io-index)",
  "lmdb-sys 0.8.0 (git+https://github.com/pantsbuild/lmdb-rs.git?rev=06bdfbfc6348f6804127176e561843f214fc17f8)",
 ]
 
@@ -1448,7 +1510,7 @@ version = "0.8.0"
 source = "git+https://github.com/pantsbuild/lmdb-rs.git?rev=06bdfbfc6348f6804127176e561843f214fc17f8#06bdfbfc6348f6804127176e561843f214fc17f8"
 dependencies = [
  "cc 1.0.50 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.66 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.68 (registry+https://github.com/rust-lang/crates.io-index)",
  "pkg-config 0.3.17 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -1476,7 +1538,7 @@ name = "lock_api"
 version = "0.1.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "owning_ref 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "owning_ref 0.4.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "scopeguard 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -1501,7 +1563,7 @@ name = "logging"
 version = "0.0.1"
 dependencies = [
  "cargo 0.34.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "chrono 0.4.10 (registry+https://github.com/rust-lang/crates.io-index)",
+ "chrono 0.4.11 (registry+https://github.com/rust-lang/crates.io-index)",
  "lazy_static 1.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "num_enum 0.4.3 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -1529,7 +1591,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
 name = "memchr"
-version = "2.3.2"
+version = "2.3.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
@@ -1539,7 +1601,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
 name = "mime_guess"
-version = "2.0.1"
+version = "2.0.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "mime 0.3.16 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -1564,7 +1626,7 @@ dependencies = [
  "fuchsia-zircon-sys 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "iovec 0.1.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "kernel32-sys 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.66 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.68 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "miow 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "net2 0.2.33 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -1572,6 +1634,17 @@ dependencies = [
  "winapi 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "mio-extras"
+version = "2.0.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "lazycell 1.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "mio 0.6.21 (registry+https://github.com/rust-lang/crates.io-index)",
+ "slab 0.4.2 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "mio-named-pipes"
 version = "0.1.6"
@@ -1589,7 +1662,7 @@ version = "0.6.7"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "iovec 0.1.4 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.66 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.68 (registry+https://github.com/rust-lang/crates.io-index)",
  "mio 0.6.21 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -1659,17 +1732,29 @@ version = "0.2.33"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "cfg-if 0.1.10 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.66 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.68 (registry+https://github.com/rust-lang/crates.io-index)",
  "winapi 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
-name = "nom"
-version = "4.2.3"
-source = "registry+https://github.com/rust-lang/crates.io-index"
+name = "notify"
+version = "5.0.0-pre.1"
+source = "git+https://github.com/notify-rs/notify?rev=fba00891d9105e2f581c69fbe415a58cb7966fdd#fba00891d9105e2f581c69fbe415a58cb7966fdd"
 dependencies = [
- "memchr 2.3.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "version_check 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "anymap 0.12.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "bitflags 1.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "chashmap 2.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "crossbeam-channel 0.3.9 (registry+https://github.com/rust-lang/crates.io-index)",
+ "filetime 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "fsevent 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "fsevent-sys 2.0.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "inotify 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "kernel32-sys 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.68 (registry+https://github.com/rust-lang/crates.io-index)",
+ "mio 0.6.21 (registry+https://github.com/rust-lang/crates.io-index)",
+ "mio-extras 2.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
+ "walkdir 2.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "winapi 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -1748,8 +1833,8 @@ name = "num_cpus"
 version = "1.12.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "hermit-abi 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.66 (registry+https://github.com/rust-lang/crates.io-index)",
+ "hermit-abi 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.68 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -1767,9 +1852,9 @@ version = "0.4.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "proc-macro-crate 0.1.4 (registry+https://github.com/rust-lang/crates.io-index)",
- "proc-macro2 1.0.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "quote 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 1.0.14 (registry+https://github.com/rust-lang/crates.io-index)",
+ "proc-macro2 1.0.9 (registry+https://github.com/rust-lang/crates.io-index)",
+ "quote 1.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 1.0.16 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -1787,8 +1872,8 @@ name = "opener"
 version = "0.3.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "failure 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
- "failure_derive 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
+ "failure 0.1.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "failure_derive 0.1.7 (registry+https://github.com/rust-lang/crates.io-index)",
  "winapi 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -1801,7 +1886,7 @@ dependencies = [
  "cfg-if 0.1.10 (registry+https://github.com/rust-lang/crates.io-index)",
  "foreign-types 0.3.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "lazy_static 1.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.66 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.68 (registry+https://github.com/rust-lang/crates.io-index)",
  "openssl-sys 0.9.54 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -1817,7 +1902,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "autocfg 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "cc 1.0.50 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.66 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.68 (registry+https://github.com/rust-lang/crates.io-index)",
  "pkg-config 0.3.17 (registry+https://github.com/rust-lang/crates.io-index)",
  "vcpkg 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
@@ -1829,12 +1914,29 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
 name = "owning_ref"
-version = "0.4.0"
+version = "0.3.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "stable_deref_trait 1.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "owning_ref"
+version = "0.4.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "stable_deref_trait 1.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "parking_lot"
+version = "0.4.8"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "owning_ref 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parking_lot_core 0.2.14 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "parking_lot"
 version = "0.6.4"
@@ -1844,12 +1946,23 @@ dependencies = [
  "parking_lot_core 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "parking_lot_core"
+version = "0.2.14"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "libc 0.2.68 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rand 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)",
+ "smallvec 0.6.13 (registry+https://github.com/rust-lang/crates.io-index)",
+ "winapi 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "parking_lot_core"
 version = "0.3.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "libc 0.2.66 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.68 (registry+https://github.com/rust-lang/crates.io-index)",
  "rand 0.5.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc_version 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "smallvec 0.6.13 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -1888,9 +2001,9 @@ name = "pin-project-internal"
 version = "0.4.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "proc-macro2 1.0.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "quote 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 1.0.14 (registry+https://github.com/rust-lang/crates.io-index)",
+ "proc-macro2 1.0.9 (registry+https://github.com/rust-lang/crates.io-index)",
+ "quote 1.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 1.0.16 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -1923,17 +2036,17 @@ dependencies = [
 
 [[package]]
 name = "proc-macro-hack"
-version = "0.5.11"
+version = "0.5.12"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "proc-macro2 1.0.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "quote 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 1.0.14 (registry+https://github.com/rust-lang/crates.io-index)",
+ "proc-macro2 1.0.9 (registry+https://github.com/rust-lang/crates.io-index)",
+ "quote 1.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 1.0.16 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
 name = "proc-macro-nested"
-version = "0.1.3"
+version = "0.1.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
@@ -1946,7 +2059,7 @@ dependencies = [
 
 [[package]]
 name = "proc-macro2"
-version = "1.0.8"
+version = "1.0.9"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "unicode-xid 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -1963,7 +2076,7 @@ dependencies = [
  "bytes 0.4.12 (registry+https://github.com/rust-lang/crates.io-index)",
  "concrete_time 0.0.1",
  "copy_dir 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "derivative 1.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "derivative 1.0.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "digest 0.8.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "fs 0.0.1",
  "futures 0.1.29 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -1972,15 +2085,15 @@ dependencies = [
  "hashing 0.0.1",
  "itertools 0.8.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "lazy_static 1.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.66 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.68 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "maplit 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "mock 0.0.1",
  "nails 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "parking_lot 0.6.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "protobuf 2.0.6 (git+https://github.com/pantsbuild/rust-protobuf?rev=171611c33ec92f07e1b7107327f6d0139a7afebf)",
- "regex 1.3.4 (registry+https://github.com/rust-lang/crates.io-index)",
- "serde 1.0.104 (registry+https://github.com/rust-lang/crates.io-index)",
+ "regex 1.3.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde 1.0.105 (registry+https://github.com/rust-lang/crates.io-index)",
  "sha2 0.8.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "sharded_lmdb 0.0.1",
  "spectral 0.6.0 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -2042,7 +2155,7 @@ name = "prost-derive"
 version = "0.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "failure 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
+ "failure 0.1.7 (registry+https://github.com/rust-lang/crates.io-index)",
  "itertools 0.7.11 (registry+https://github.com/rust-lang/crates.io-index)",
  "proc-macro2 0.4.30 (registry+https://github.com/rust-lang/crates.io-index)",
  "quote 0.6.13 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -2077,10 +2190,10 @@ dependencies = [
 
 [[package]]
 name = "protoc"
-version = "2.10.1"
+version = "2.10.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "log 0.3.9 (registry+https://github.com/rust-lang/crates.io-index)",
+ "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -2088,12 +2201,12 @@ name = "protoc-grpcio"
 version = "0.2.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "failure 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
+ "failure 0.1.7 (registry+https://github.com/rust-lang/crates.io-index)",
  "grpcio-compiler 0.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "mktemp 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "protobuf 2.0.6 (git+https://github.com/pantsbuild/rust-protobuf?rev=171611c33ec92f07e1b7107327f6d0139a7afebf)",
  "protobuf-codegen 2.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
- "protoc 2.10.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "protoc 2.10.2 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -2111,10 +2224,10 @@ dependencies = [
 
 [[package]]
 name = "quote"
-version = "1.0.2"
+version = "1.0.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "proc-macro2 1.0.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "proc-macro2 1.0.9 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -2122,7 +2235,7 @@ name = "rand"
 version = "0.3.23"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "libc 0.2.66 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.68 (registry+https://github.com/rust-lang/crates.io-index)",
  "rand 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -2132,7 +2245,7 @@ version = "0.4.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "fuchsia-cprng 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.66 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.68 (registry+https://github.com/rust-lang/crates.io-index)",
  "rand_core 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "rdrand 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "winapi 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -2145,7 +2258,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "cloudabi 0.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "fuchsia-cprng 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.66 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.68 (registry+https://github.com/rust-lang/crates.io-index)",
  "rand_core 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "winapi 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
@@ -2156,7 +2269,7 @@ version = "0.6.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "autocfg 0.1.7 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.66 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.68 (registry+https://github.com/rust-lang/crates.io-index)",
  "rand_chacha 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "rand_core 0.4.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "rand_hc 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -2174,8 +2287,8 @@ version = "0.7.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "getrandom 0.1.14 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.66 (registry+https://github.com/rust-lang/crates.io-index)",
- "rand_chacha 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.68 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rand_chacha 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "rand_core 0.5.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "rand_hc 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
@@ -2191,10 +2304,10 @@ dependencies = [
 
 [[package]]
 name = "rand_chacha"
-version = "0.2.1"
+version = "0.2.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "c2-chacha 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "ppv-lite86 0.2.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "rand_core 0.5.1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -2248,7 +2361,7 @@ name = "rand_jitter"
 version = "0.1.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "libc 0.2.66 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.68 (registry+https://github.com/rust-lang/crates.io-index)",
  "rand_core 0.4.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "winapi 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
@@ -2260,7 +2373,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "cloudabi 0.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "fuchsia-cprng 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.66 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.68 (registry+https://github.com/rust-lang/crates.io-index)",
  "rand_core 0.4.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "rdrand 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "winapi 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -2316,18 +2429,18 @@ dependencies = [
 
 [[package]]
 name = "regex"
-version = "1.3.4"
+version = "1.3.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "aho-corasick 0.7.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "memchr 2.3.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "regex-syntax 0.6.14 (registry+https://github.com/rust-lang/crates.io-index)",
+ "aho-corasick 0.7.10 (registry+https://github.com/rust-lang/crates.io-index)",
+ "memchr 2.3.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "regex-syntax 0.6.17 (registry+https://github.com/rust-lang/crates.io-index)",
  "thread_local 1.0.1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
 name = "regex-syntax"
-version = "0.6.14"
+version = "0.6.17"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
@@ -2352,23 +2465,23 @@ dependencies = [
  "http-body 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "hyper 0.13.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "hyper-rustls 0.20.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "js-sys 0.3.35 (registry+https://github.com/rust-lang/crates.io-index)",
+ "js-sys 0.3.36 (registry+https://github.com/rust-lang/crates.io-index)",
  "lazy_static 1.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "mime 0.3.16 (registry+https://github.com/rust-lang/crates.io-index)",
- "mime_guess 2.0.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "mime_guess 2.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "percent-encoding 2.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "pin-project-lite 0.1.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustls 0.17.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "serde 1.0.104 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde 1.0.105 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde_urlencoded 0.6.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "time 0.1.42 (registry+https://github.com/rust-lang/crates.io-index)",
  "tokio 0.2.13 (registry+https://github.com/rust-lang/crates.io-index)",
  "tokio-rustls 0.13.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "url 2.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
- "wasm-bindgen 0.2.58 (registry+https://github.com/rust-lang/crates.io-index)",
- "wasm-bindgen-futures 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "web-sys 0.3.35 (registry+https://github.com/rust-lang/crates.io-index)",
+ "wasm-bindgen 0.2.59 (registry+https://github.com/rust-lang/crates.io-index)",
+ "wasm-bindgen-futures 0.4.9 (registry+https://github.com/rust-lang/crates.io-index)",
+ "web-sys 0.3.36 (registry+https://github.com/rust-lang/crates.io-index)",
  "webpki-roots 0.18.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "winreg 0.6.2 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
@@ -2380,10 +2493,10 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "cc 1.0.50 (registry+https://github.com/rust-lang/crates.io-index)",
  "lazy_static 1.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.66 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.68 (registry+https://github.com/rust-lang/crates.io-index)",
  "spin 0.5.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "untrusted 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "web-sys 0.3.35 (registry+https://github.com/rust-lang/crates.io-index)",
+ "web-sys 0.3.36 (registry+https://github.com/rust-lang/crates.io-index)",
  "winapi 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -2399,7 +2512,7 @@ dependencies = [
  "base64 0.11.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "blake2b_simd 0.5.10 (registry+https://github.com/rust-lang/crates.io-index)",
  "constant_time_eq 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
- "crossbeam-utils 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "crossbeam-utils 0.7.2 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -2430,9 +2543,9 @@ name = "rustfix"
 version = "0.4.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "failure 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
+ "failure 0.1.7 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "serde 1.0.104 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde 1.0.105 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde_json 1.0.48 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -2461,7 +2574,7 @@ dependencies = [
 
 [[package]]
 name = "ryu"
-version = "1.0.2"
+version = "1.0.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
@@ -2512,7 +2625,7 @@ version = "0.4.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "core-foundation-sys 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.66 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.68 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -2521,7 +2634,7 @@ version = "0.9.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "semver-parser 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "serde 1.0.104 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde 1.0.105 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -2531,20 +2644,20 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
 name = "serde"
-version = "1.0.104"
+version = "1.0.105"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "serde_derive 1.0.104 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde_derive 1.0.105 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
 name = "serde_derive"
-version = "1.0.104"
+version = "1.0.105"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "proc-macro2 1.0.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "quote 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 1.0.14 (registry+https://github.com/rust-lang/crates.io-index)",
+ "proc-macro2 1.0.9 (registry+https://github.com/rust-lang/crates.io-index)",
+ "quote 1.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 1.0.16 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -2552,7 +2665,7 @@ name = "serde_ignored"
 version = "0.0.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "serde 1.0.104 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde 1.0.105 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -2561,16 +2674,16 @@ version = "1.0.48"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "itoa 0.4.5 (registry+https://github.com/rust-lang/crates.io-index)",
- "ryu 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "serde 1.0.104 (registry+https://github.com/rust-lang/crates.io-index)",
+ "ryu 1.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde 1.0.105 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
 name = "serde_test"
-version = "1.0.104"
+version = "1.0.105"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "serde 1.0.104 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde 1.0.105 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -2580,7 +2693,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "dtoa 0.4.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "itoa 0.4.5 (registry+https://github.com/rust-lang/crates.io-index)",
- "serde 1.0.104 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde 1.0.105 (registry+https://github.com/rust-lang/crates.io-index)",
  "url 2.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -2632,8 +2745,8 @@ name = "signal-hook-registry"
 version = "1.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "arc-swap 0.4.4 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.66 (registry+https://github.com/rust-lang/crates.io-index)",
+ "arc-swap 0.4.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.68 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -2641,7 +2754,7 @@ name = "simplelog"
 version = "0.7.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "chrono 0.4.10 (registry+https://github.com/rust-lang/crates.io-index)",
+ "chrono 0.4.11 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "term 0.6.1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
@@ -2678,16 +2791,11 @@ version = "0.3.11"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "cfg-if 0.1.10 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.66 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.68 (registry+https://github.com/rust-lang/crates.io-index)",
  "redox_syscall 0.1.56 (registry+https://github.com/rust-lang/crates.io-index)",
  "winapi 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
-[[package]]
-name = "sourcefile"
-version = "0.1.4"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-
 [[package]]
 name = "spectral"
 version = "0.6.0"
@@ -2729,8 +2837,8 @@ dependencies = [
  "mock 0.0.1",
  "parking_lot 0.6.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "protobuf 2.0.6 (git+https://github.com/pantsbuild/rust-protobuf?rev=171611c33ec92f07e1b7107327f6d0139a7afebf)",
- "serde 1.0.104 (registry+https://github.com/rust-lang/crates.io-index)",
- "serde_derive 1.0.104 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde 1.0.105 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde_derive 1.0.105 (registry+https://github.com/rust-lang/crates.io-index)",
  "serverset 0.0.1",
  "sha2 0.8.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "sharded_lmdb 0.0.1",
@@ -2798,11 +2906,11 @@ dependencies = [
 
 [[package]]
 name = "syn"
-version = "1.0.14"
+version = "1.0.16"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "proc-macro2 1.0.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "quote 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "proc-macro2 1.0.9 (registry+https://github.com/rust-lang/crates.io-index)",
+ "quote 1.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "unicode-xid 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -2811,9 +2919,9 @@ name = "synstructure"
 version = "0.12.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "proc-macro2 1.0.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "quote 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 1.0.14 (registry+https://github.com/rust-lang/crates.io-index)",
+ "proc-macro2 1.0.9 (registry+https://github.com/rust-lang/crates.io-index)",
+ "quote 1.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 1.0.16 (registry+https://github.com/rust-lang/crates.io-index)",
  "unicode-xid 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -2823,7 +2931,7 @@ version = "0.4.26"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "filetime 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.66 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.68 (registry+https://github.com/rust-lang/crates.io-index)",
  "redox_syscall 0.1.56 (registry+https://github.com/rust-lang/crates.io-index)",
  "xattr 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
@@ -2832,7 +2940,7 @@ dependencies = [
 name = "tar_api"
 version = "0.0.1"
 dependencies = [
- "flate2 1.0.13 (registry+https://github.com/rust-lang/crates.io-index)",
+ "flate2 1.0.14 (registry+https://github.com/rust-lang/crates.io-index)",
  "tar 0.4.26 (registry+https://github.com/rust-lang/crates.io-index)",
  "tempfile 3.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "testutil 0.0.1",
@@ -2863,7 +2971,7 @@ version = "3.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "cfg-if 0.1.10 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.66 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.68 (registry+https://github.com/rust-lang/crates.io-index)",
  "rand 0.7.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "redox_syscall 0.1.56 (registry+https://github.com/rust-lang/crates.io-index)",
  "remove_dir_all 0.5.2 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -2892,7 +3000,7 @@ name = "termion"
 version = "1.5.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "libc 0.2.66 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.68 (registry+https://github.com/rust-lang/crates.io-index)",
  "numtoa 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "redox_syscall 0.1.56 (registry+https://github.com/rust-lang/crates.io-index)",
  "redox_termios 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -2936,7 +3044,7 @@ name = "time"
 version = "0.1.42"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "libc 0.2.66 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.68 (registry+https://github.com/rust-lang/crates.io-index)",
  "redox_syscall 0.1.56 (registry+https://github.com/rust-lang/crates.io-index)",
  "winapi 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
@@ -2950,8 +3058,8 @@ dependencies = [
  "fnv 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "iovec 0.1.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "lazy_static 1.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.66 (registry+https://github.com/rust-lang/crates.io-index)",
- "memchr 2.3.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.68 (registry+https://github.com/rust-lang/crates.io-index)",
+ "memchr 2.3.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "mio 0.6.21 (registry+https://github.com/rust-lang/crates.io-index)",
  "mio-named-pipes 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "mio-uds 0.6.7 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -2959,7 +3067,7 @@ dependencies = [
  "pin-project-lite 0.1.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "signal-hook-registry 1.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "slab 0.4.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "tokio-macros 0.2.4 (registry+https://github.com/rust-lang/crates.io-index)",
+ "tokio-macros 0.2.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "winapi 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -2972,6 +3080,24 @@ dependencies = [
  "tokio-io 0.1.13 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "tokio-current-thread"
+version = "0.1.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "futures 0.1.29 (registry+https://github.com/rust-lang/crates.io-index)",
+ "tokio-executor 0.1.10 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "tokio-executor"
+version = "0.1.10"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "crossbeam-utils 0.7.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "futures 0.1.29 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "tokio-io"
 version = "0.1.13"
@@ -2984,12 +3110,12 @@ dependencies = [
 
 [[package]]
 name = "tokio-macros"
-version = "0.2.4"
+version = "0.2.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "proc-macro2 1.0.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "quote 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 1.0.14 (registry+https://github.com/rust-lang/crates.io-index)",
+ "proc-macro2 1.0.9 (registry+https://github.com/rust-lang/crates.io-index)",
+ "quote 1.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 1.0.16 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -3021,7 +3147,7 @@ name = "toml"
 version = "0.4.10"
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 ]
 
 [[package]]
@@ -3029,7 +3155,7 @@ name = "toml"
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- "serde 1.0.104 (registry+https://github.com/rust-lang/crates.io-index)",
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@@ -3152,7 +3278,7 @@ name = "uname"
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- "libc 0.2.66 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.68 (registry+https://github.com/rust-lang/crates.io-index)",
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 [[package]]
@@ -3229,7 +3355,7 @@ name = "url_serde"
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- "serde 1.0.104 (registry+https://github.com/rust-lang/crates.io-index)",
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@@ -3260,11 +3386,6 @@ name = "vec_map"
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-[[package]]
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@@ -3305,91 +3426,73 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 
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 [[package]]
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 [[package]]
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-"checksum wasm-bindgen-macro-support 0.2.58 (registry+https://github.com/rust-lang/crates.io-index)" = "e85031354f25eaebe78bb7db1c3d86140312a911a106b2e29f9cc440ce3e7668"
-"checksum wasm-bindgen-shared 0.2.58 (registry+https://github.com/rust-lang/crates.io-index)" = "f5e7e61fc929f4c0dddb748b102ebf9f632e2b8d739f2016542b4de2965a9601"
-"checksum wasm-bindgen-webidl 0.2.58 (registry+https://github.com/rust-lang/crates.io-index)" = "ef012a0d93fc0432df126a8eaf547b2dce25a8ce9212e1d3cbeef5c11157975d"
-"checksum web-sys 0.3.35 (registry+https://github.com/rust-lang/crates.io-index)" = "aaf97caf6aa8c2b1dac90faf0db529d9d63c93846cca4911856f78a83cebf53b"
+"checksum wasm-bindgen 0.2.59 (registry+https://github.com/rust-lang/crates.io-index)" = "3557c397ab5a8e347d434782bcd31fc1483d927a6826804cec05cc792ee2519d"
+"checksum wasm-bindgen-backend 0.2.59 (registry+https://github.com/rust-lang/crates.io-index)" = "e0da9c9a19850d3af6df1cb9574970b566d617ecfaf36eb0b706b6f3ef9bd2f8"
+"checksum wasm-bindgen-futures 0.4.9 (registry+https://github.com/rust-lang/crates.io-index)" = "457414a91863c0ec00090dba537f88ab955d93ca6555862c29b6d860990b8a8a"
+"checksum wasm-bindgen-macro 0.2.59 (registry+https://github.com/rust-lang/crates.io-index)" = "0f6fde1d36e75a714b5fe0cffbb78978f222ea6baebb726af13c78869fdb4205"
+"checksum wasm-bindgen-macro-support 0.2.59 (registry+https://github.com/rust-lang/crates.io-index)" = "25bda4168030a6412ea8a047e27238cadf56f0e53516e1e83fec0a8b7c786f6d"
+"checksum wasm-bindgen-shared 0.2.59 (registry+https://github.com/rust-lang/crates.io-index)" = "fc9f36ad51f25b0219a3d4d13b90eb44cd075dff8b6280cca015775d7acaddd8"
+"checksum web-sys 0.3.36 (registry+https://github.com/rust-lang/crates.io-index)" = "721c6263e2c66fd44501cc5efbfa2b7dfa775d13e4ea38c46299646ed1f9c70a"
 "checksum webpki 0.21.2 (registry+https://github.com/rust-lang/crates.io-index)" = "f1f50e1972865d6b1adb54167d1c8ed48606004c2c9d0ea5f1eeb34d95e863ef"
 "checksum webpki-roots 0.18.0 (registry+https://github.com/rust-lang/crates.io-index)" = "91cd5736df7f12a964a5067a12c62fa38e1bd8080aff1f80bc29be7c80d19ab4"
-"checksum weedle 0.10.0 (registry+https://github.com/rust-lang/crates.io-index)" = "3bb43f70885151e629e2a19ce9e50bd730fd436cfd4b666894c9ce4de9141164"
 "checksum which 2.0.1 (registry+https://github.com/rust-lang/crates.io-index)" = "b57acb10231b9493c8472b20cb57317d0679a49e0bdbee44b3b803a6473af164"
 "checksum winapi 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)" = "167dc9d6949a9b857f3451275e911c3f44255842c1f7a76f33c55103a909087a"
 "checksum winapi 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)" = "8093091eeb260906a183e6ae1abdba2ef5ef2257a21801128899c3fc699229c6"
diff --git a/src/rust/engine/Cargo.toml b/src/rust/engine/Cargo.toml
index 232d4856993..4b32107f994 100644
--- a/src/rust/engine/Cargo.toml
+++ b/src/rust/engine/Cargo.toml
@@ -81,14 +81,17 @@ default-members = [
 ]
 
 [dependencies]
+async_semaphore = { path = "async_semaphore" }
 async-trait = "0.1"
 boxfuture = { path = "boxfuture" }
 bytes = "0.4.5"
 concrete_time = { path = "concrete_time" }
+crossbeam-channel = "0.3"
 fnv = "1.0.5"
 fs = { path = "fs" }
 futures01 = { package = "futures", version = "0.1" }
 futures = { version = "0.3", features = ["compat"] }
+futures-locks = "0.3.0"
 graph = { path = "graph" }
 hashing = { path = "hashing" }
 indexmap = "1.0.2"
@@ -98,6 +101,11 @@ log = "0.4"
 logging = { path = "logging" }
 num_cpus = "1"
 num_enum = "0.4"
+# notify is currently an experimental API, we are pinning to https://docs.rs/notify/5.0.0-pre.1/notify/
+# because the latest prerelease at time of writing has removed the debounced watcher which we would like to use.
+# The author suggests they will add the debounced watcher back into the stable 5.0.0 release. When that happens
+# we can move to it.
+notify = { git = "https://github.com/notify-rs/notify", rev = "fba00891d9105e2f581c69fbe415a58cb7966fdd" }
 parking_lot = "0.6"
 process_execution = { path = "process_execution" }
 rand = "0.6"
@@ -115,6 +123,11 @@ url = "2.1"
 uuid = { version = "0.7", features = ["v4"] }
 workunit_store = { path = "workunit_store" }
 
+[dev-dependencies]
+testutil = { path = "./testutil" }
+fs = { path = "./fs" }
+env_logger = "0.5.4"
+
 [patch.crates-io]
 # TODO: Remove patch when we can upgrade to an official released version of protobuf with a fix.
 # See: https://github.com/pantsbuild/pants/issues/7760 for context.
diff --git a/src/rust/engine/graph/src/entry.rs b/src/rust/engine/graph/src/entry.rs
index 5f2627c3b8b..c8254a73edd 100644
--- a/src/rust/engine/graph/src/entry.rs
+++ b/src/rust/engine/graph/src/entry.rs
@@ -18,10 +18,10 @@ use boxfuture::{BoxFuture, Boxable};
 /// the Node was `cleared`), the work is discarded. See `Entry::complete` for more information.
 ///
 #[derive(Clone, Copy, Debug, Eq, PartialEq)]
-pub(crate) struct RunToken(u32);
+pub struct RunToken(u32);
 
 impl RunToken {
-  fn initial() -> RunToken {
+  pub fn initial() -> RunToken {
     RunToken(0)
   }
 
@@ -40,10 +40,10 @@ impl RunToken {
 /// incremented when the output of a node has changed.
 ///
 #[derive(Clone, Copy, Debug, Eq, PartialEq)]
-pub(crate) struct Generation(u32);
+pub struct Generation(u32);
 
 impl Generation {
-  fn initial() -> Generation {
+  pub fn initial() -> Generation {
     Generation(0)
   }
 
@@ -65,7 +65,7 @@ impl Generation {
 /// If the value is Clean, the consumer can simply use the value as-is.
 ///
 #[derive(Clone, Debug)]
-pub(crate) enum EntryResult<N: Node> {
+pub enum EntryResult<N: Node> {
   Clean(Result<N::Item, N::Error>),
   Dirty(Result<N::Item, N::Error>),
   Uncacheable(
@@ -118,7 +118,7 @@ impl<N: Node> AsRef<Result<N::Item, N::Error>> for EntryResult<N> {
 
 #[allow(clippy::type_complexity)]
 #[derive(Debug)]
-pub(crate) enum EntryState<N: Node> {
+pub enum EntryState<N: Node> {
   // A node that has either been explicitly cleared, or has not yet started Running. In this state
   // there is no need for a dirty bit because the RunToken is either in its initial state, or has
   // been explicitly incremented when the node was cleared.
@@ -174,7 +174,7 @@ pub struct Entry<N: Node> {
   // maps is painful.
   node: N,
 
-  state: Arc<Mutex<EntryState<N>>>,
+  pub state: Arc<Mutex<EntryState<N>>>,
 }
 
 impl<N: Node> Entry<N> {
diff --git a/src/rust/engine/graph/src/lib.rs b/src/rust/engine/graph/src/lib.rs
index 139968308f4..51a60a546d8 100644
--- a/src/rust/engine/graph/src/lib.rs
+++ b/src/rust/engine/graph/src/lib.rs
@@ -29,10 +29,12 @@ use hashing;
 
 use petgraph;
 
-mod entry;
+// make the entry module public for testing purposes. We use it to contruct mock
+// graph entries in the notify watch tests.
+pub mod entry;
 mod node;
 
-pub use crate::entry::Entry;
+pub use crate::entry::{Entry, EntryState};
 use crate::entry::{Generation, RunToken};
 
 use std::collections::binary_heap::BinaryHeap;
@@ -1009,6 +1011,43 @@ impl<N: Node> Graph<N> {
   }
 }
 
+// This module provides a trait which contains functions that
+// should only be used in tests. A user must explicitly import the trait
+// to use the extra test functions, and they should only be imported into
+// test modules.
+pub mod test_support {
+  use super::{EntryId, EntryState, Graph, Node};
+  pub trait TestGraph<N: Node> {
+    fn set_fixture_entry_state_for_id(&self, id: EntryId, state: EntryState<N>);
+    fn add_fixture_entry(&self, node: N) -> EntryId;
+    fn entry_state(&self, id: EntryId) -> &str;
+  }
+  impl<N: Node> TestGraph<N> for Graph<N> {
+    fn set_fixture_entry_state_for_id(&self, id: EntryId, state: EntryState<N>) {
+      let mut inner = self.inner.lock();
+      let entry = inner.entry_for_id_mut(id).unwrap();
+      let mut entry_state = entry.state.lock();
+      *entry_state = state;
+    }
+
+    fn add_fixture_entry(&self, node: N) -> EntryId {
+      let mut inner = self.inner.lock();
+      inner.ensure_entry(node)
+    }
+
+    fn entry_state(&self, id: EntryId) -> &str {
+      let mut inner = self.inner.lock();
+      let entry = inner.entry_for_id_mut(id).unwrap();
+      let entry_state = entry.state.lock();
+      match *entry_state {
+        EntryState::Completed { .. } => "completed",
+        EntryState::Running { .. } => "running",
+        EntryState::NotStarted { .. } => "not started",
+      }
+    }
+  }
+}
+
 ///
 /// Represents the state of a particular walk through a Graph. Implements Iterator and has the same
 /// lifetime as the Graph itself.
diff --git a/src/rust/engine/src/context.rs b/src/rust/engine/src/context.rs
index 3a4a0852256..4c28d611a11 100644
--- a/src/rust/engine/src/context.rs
+++ b/src/rust/engine/src/context.rs
@@ -17,6 +17,7 @@ use crate::nodes::{NodeKey, WrappedNode};
 use crate::scheduler::Session;
 use crate::tasks::{Rule, Tasks};
 use crate::types::Types;
+use crate::watch::InvalidationWatcher;
 use boxfuture::{BoxFuture, Boxable};
 use core::clone::Clone;
 use fs::{safe_create_dir_all_ioerror, PosixFS};
@@ -43,7 +44,7 @@ const GIGABYTES: usize = 1024 * 1024 * 1024;
 /// https://github.com/tokio-rs/tokio/issues/369 is resolved.
 ///
 pub struct Core {
-  pub graph: Graph<NodeKey>,
+  pub graph: Arc<Graph<NodeKey>>,
   pub tasks: Tasks,
   pub rule_graph: RuleGraph<Rule>,
   pub types: Types,
@@ -53,6 +54,7 @@ pub struct Core {
   pub command_runner: Box<dyn process_execution::CommandRunner>,
   pub http_client: reqwest::Client,
   pub vfs: PosixFS,
+  pub watcher: InvalidationWatcher,
   pub build_root: PathBuf,
 }
 
@@ -232,12 +234,15 @@ impl Core {
         process_execution_metadata,
       ));
     }
+    let graph = Arc::new(Graph::new());
+    let watcher =
+      InvalidationWatcher::new(Arc::downgrade(&graph), executor.clone(), build_root.clone())?;
 
     let http_client = reqwest::Client::new();
     let rule_graph = RuleGraph::new(tasks.as_map(), root_subject_types);
 
     Ok(Core {
-      graph: Graph::new(),
+      graph: graph,
       tasks: tasks,
       rule_graph: rule_graph,
       types: types,
@@ -250,7 +255,8 @@ impl Core {
       // exceptions, rather than as panics.
       vfs: PosixFS::new(&build_root, &ignore_patterns, executor)
         .map_err(|e| format!("Could not initialize VFS: {:?}", e))?,
-      build_root: build_root,
+      build_root,
+      watcher,
     })
   }
 
diff --git a/src/rust/engine/src/core.rs b/src/rust/engine/src/core.rs
index 2eb2faa27cb..ae343980a35 100644
--- a/src/rust/engine/src/core.rs
+++ b/src/rust/engine/src/core.rs
@@ -289,6 +289,7 @@ pub enum Failure {
   Invalidated,
   /// A rule raised an exception.
   Throw(Value, String),
+  FileWatch(String),
 }
 
 impl fmt::Display for Failure {
@@ -296,6 +297,7 @@ impl fmt::Display for Failure {
     match self {
       Failure::Invalidated => write!(f, "Exhausted retries due to changed files."),
       Failure::Throw(exc, _) => write!(f, "{}", externs::val_to_str(exc)),
+      Failure::FileWatch(failure) => write!(f, "{}", failure),
     }
   }
 }
diff --git a/src/rust/engine/src/externs.rs b/src/rust/engine/src/externs.rs
index 33c9b745a6f..68fcf11e404 100644
--- a/src/rust/engine/src/externs.rs
+++ b/src/rust/engine/src/externs.rs
@@ -462,6 +462,7 @@ impl From<Result<Value, Failure>> for PyResult {
         let val = match f {
           f @ Failure::Invalidated => create_exception(&format!("{}", f)),
           Failure::Throw(exc, _) => exc,
+          Failure::FileWatch(failure) => create_exception(&failure),
         };
         PyResult {
           is_throw: true,
diff --git a/src/rust/engine/src/lib.rs b/src/rust/engine/src/lib.rs
index 90cb5465c49..0d6efd13dd4 100644
--- a/src/rust/engine/src/lib.rs
+++ b/src/rust/engine/src/lib.rs
@@ -40,6 +40,7 @@ mod scheduler;
 mod selectors;
 mod tasks;
 mod types;
+mod watch;
 
 pub use crate::context::Core;
 pub use crate::core::{Function, Key, Params, TypeId, Value};
@@ -49,3 +50,6 @@ pub use crate::scheduler::{
 };
 pub use crate::tasks::{Rule, Tasks};
 pub use crate::types::Types;
+
+#[cfg(test)]
+mod watch_tests;
diff --git a/src/rust/engine/src/nodes.rs b/src/rust/engine/src/nodes.rs
index 1d84e95a651..8a477e00683 100644
--- a/src/rust/engine/src/nodes.rs
+++ b/src/rust/engine/src/nodes.rs
@@ -941,7 +941,7 @@ impl NodeVisualizer<NodeKey> for Visualizer {
     let max_colors = 12;
     match entry.peek(context) {
       None => "white".to_string(),
-      Some(Err(Failure::Throw(..))) => "4".to_string(),
+      Some(Err(Failure::Throw(..))) | Some(Err(Failure::FileWatch(..))) => "4".to_string(),
       Some(Err(Failure::Invalidated)) => "12".to_string(),
       Some(Ok(_)) => {
         let viz_colors_len = self.viz_colors.len();
@@ -962,6 +962,7 @@ impl NodeTracer<NodeKey> for Tracer {
     match result {
       Some(Err(Failure::Invalidated)) => false,
       Some(Err(Failure::Throw(..))) => false,
+      Some(Err(Failure::FileWatch(..))) => false,
       Some(Ok(_)) => true,
       None => {
         // A Node with no state is either still running, or effectively cancelled
@@ -986,6 +987,7 @@ impl NodeTracer<NodeKey> for Tracer {
           .join("\n")
       ),
       Some(Err(Failure::Invalidated)) => "Invalidated".to_string(),
+      Some(Err(Failure::FileWatch(failure))) => format!("FileWatch failed: {}", failure),
     }
   }
 }
@@ -1067,17 +1069,32 @@ impl Node for NodeKey {
 
     scope_task_parent_id(maybe_span_id, async move {
       let context2 = context.clone();
-      let result = match self {
-        NodeKey::DigestFile(n) => n.run(context).map(NodeResult::from).compat().await,
-        NodeKey::DownloadedFile(n) => n.run(context).map(NodeResult::from).compat().await,
-        NodeKey::MultiPlatformExecuteProcess(n) => {
-          n.run(context).map(NodeResult::from).compat().await
-        }
-        NodeKey::ReadLink(n) => n.run(context).map(NodeResult::from).compat().await,
-        NodeKey::Scandir(n) => n.run(context).map(NodeResult::from).compat().await,
-        NodeKey::Select(n) => n.run(context).map(NodeResult::from).compat().await,
-        NodeKey::Snapshot(n) => n.run(context).map(NodeResult::from).compat().await,
-        NodeKey::Task(n) => n.run(context).map(NodeResult::from).compat().await,
+      let maybe_watch = if let Some(path) = self.fs_subject() {
+        let abs_path = context.core.build_root.join(path);
+        context
+          .core
+          .watcher
+          .watch(abs_path)
+          .map_err(|e| Failure::FileWatch(format!("{:?}", e)))
+          .await
+      } else {
+        Ok(())
+      };
+
+      let result = match maybe_watch {
+        Ok(()) => match self {
+          NodeKey::DigestFile(n) => n.run(context).map(NodeResult::from).compat().await,
+          NodeKey::DownloadedFile(n) => n.run(context).map(NodeResult::from).compat().await,
+          NodeKey::MultiPlatformExecuteProcess(n) => {
+            n.run(context).map(NodeResult::from).compat().await
+          }
+          NodeKey::ReadLink(n) => n.run(context).map(NodeResult::from).compat().await,
+          NodeKey::Scandir(n) => n.run(context).map(NodeResult::from).compat().await,
+          NodeKey::Select(n) => n.run(context).map(NodeResult::from).compat().await,
+          NodeKey::Snapshot(n) => n.run(context).map(NodeResult::from).compat().await,
+          NodeKey::Task(n) => n.run(context).map(NodeResult::from).compat().await,
+        },
+        Err(e) => Err(e),
       };
       if let Some(started_workunit) = maybe_started_workunit {
         let workunit: WorkUnit = started_workunit.finish();
diff --git a/src/rust/engine/src/scheduler.rs b/src/rust/engine/src/scheduler.rs
index a6374c547dd..3b9b202808c 100644
--- a/src/rust/engine/src/scheduler.rs
+++ b/src/rust/engine/src/scheduler.rs
@@ -14,6 +14,7 @@ use futures01::future::{self, Future};
 use crate::context::{Context, Core};
 use crate::core::{Failure, Params, TypeId, Value};
 use crate::nodes::{NodeKey, Select, Tracer, Visualizer};
+use crate::watch::InvalidationWatcher;
 use graph::{Graph, InvalidationResult};
 use hashing;
 use indexmap::IndexMap;
@@ -228,22 +229,7 @@ impl Scheduler {
   /// Invalidate the invalidation roots represented by the given Paths.
   ///
   pub fn invalidate(&self, paths: &HashSet<PathBuf>) -> usize {
-    let InvalidationResult { cleared, dirtied } =
-      self.core.graph.invalidate_from_roots(move |node| {
-        if let Some(fs_subject) = node.fs_subject() {
-          paths.contains(fs_subject)
-        } else {
-          false
-        }
-      });
-    // TODO: The rust log level is not currently set correctly in a pantsd context. To ensure that
-    // we see this even at `info` level, we set it to warn. #6004 should address this by making
-    // rust logging re-configuration an explicit step in `src/python/pants/init/logging.py`.
-    warn!(
-      "invalidation: cleared {} and dirtied {} nodes for: {:?}",
-      cleared, dirtied, paths
-    );
-    cleared + dirtied
+    InvalidationWatcher::invalidate(&self.core.graph, paths, "watchman")
   }
 
   ///
diff --git a/src/rust/engine/src/watch.rs b/src/rust/engine/src/watch.rs
new file mode 100644
index 00000000000..82ee2c9be89
--- /dev/null
+++ b/src/rust/engine/src/watch.rs
@@ -0,0 +1,198 @@
+// Copyright 2019 Pants project contributors (see CONTRIBUTORS.md).
+// Licensed under the Apache License, Version 2.0 (see LICENSE).
+
+use std::collections::HashSet;
+use std::path::PathBuf;
+use std::sync::{Arc, Weak};
+use std::thread;
+use std::time::Duration;
+
+use crossbeam_channel::{self, Receiver, RecvTimeoutError, TryRecvError};
+use log::{debug, error, info, warn};
+use notify::{RecommendedWatcher, RecursiveMode, Watcher};
+//use parking_lot::Mutex;
+use futures::compat::Future01CompatExt;
+use futures_locks::Mutex;
+use process_execution::Platform;
+use task_executor::Executor;
+
+use graph::{Graph, InvalidationResult};
+use logging;
+
+use crate::nodes::NodeKey;
+
+///
+/// An InvalidationWatcher maintains a Thread that receives events from a notify Watcher.
+///
+/// If the spawned Thread exits for any reason, InvalidationWatcher::running() will return False,
+/// and the caller should create a new InvalidationWatcher (or shut down, in some cases). Generally
+/// this will mean polling.
+///
+/// TODO: Need the above polling
+///
+/// TODO: To simplify testing the InvalidationWatcher we could create  a trait which
+/// has an `invalidate_from_roots` method  and impl it on the Graph. Then we could make the InvalidationWatcher
+/// take an argument that implements the trait.
+/// Then we wouldn't have to mock out a Graph object in watch_tests.rs. This will probably
+/// only be possible when we remove watchman invalidation, when the one code path for invaldation will be
+/// the notify background thread.
+/// Potential impl here: https://github.com/pantsbuild/pants/pull/9318#discussion_r396005978
+///
+pub struct InvalidationWatcher {
+  watcher: Arc<Mutex<RecommendedWatcher>>,
+  executor: Executor,
+  liveness: Receiver<()>,
+  current_platform: Platform,
+}
+
+impl InvalidationWatcher {
+  pub fn new(
+    graph: Weak<Graph<NodeKey>>,
+    executor: Executor,
+    build_root: PathBuf,
+  ) -> Result<InvalidationWatcher, String> {
+    // Inotify events contain canonical paths to the files being watched.
+    // If the build_root contains a symlink the paths returned in notify events
+    // wouldn't have the build_root as a prefix, and so we would miss invalidating certain nodes.
+    // We canonicalize the build_root once so this isn't a problem.
+    let canonical_build_root =
+      std::fs::canonicalize(build_root.as_path()).map_err(|e| format!("{:?}", e))?;
+    let current_platform = Platform::current()?;
+    let (watch_sender, watch_receiver) = crossbeam_channel::unbounded();
+    let mut watcher: RecommendedWatcher = Watcher::new(watch_sender, Duration::from_millis(50))
+      .map_err(|e| format!("Failed to begin watching the filesystem: {}", e))?;
+    // On darwin the notify API is much more efficient if you watch the build root
+    // recursively, so we set up that watch here and then return early when watch() is
+    // called by nodes that are running. On Linux the notify crate handles adding paths to watch
+    // much more efficiently so we do that instead on Linux.
+    if current_platform == Platform::Darwin {
+      watcher
+        .watch(canonical_build_root.clone(), RecursiveMode::Recursive)
+        .map_err(|e| {
+          format!(
+            "Failed to begin recursively watching files in the build root: {}",
+            e
+          )
+        })?
+    }
+    let wrapped_watcher = Arc::new(Mutex::new(watcher));
+
+    let (thread_liveness_sender, thread_liveness_receiver) = crossbeam_channel::unbounded();
+    thread::spawn(move || {
+      logging::set_thread_destination(logging::Destination::Pantsd);
+      loop {
+        let event_res = watch_receiver.recv_timeout(Duration::from_millis(100));
+        let graph = if let Some(g) = graph.upgrade() {
+          g
+        } else {
+          // The Graph has been dropped: we're done.
+          break;
+        };
+        match event_res {
+          Ok(Ok(ev)) => {
+            let paths: HashSet<_> = ev
+              .paths
+              .into_iter()
+              .map(|path| {
+                // relativize paths to build root.
+                let mut paths_to_invalidate: Vec<PathBuf> = vec![];
+                let path_relative_to_build_root = {
+                  if path.starts_with(&canonical_build_root) {
+                    path.strip_prefix(&canonical_build_root).unwrap().into()
+                  } else {
+                    path
+                  }
+                };
+                paths_to_invalidate.push(path_relative_to_build_root.clone());
+                if let Some(parent_dir) = path_relative_to_build_root.parent() {
+                  paths_to_invalidate.push(parent_dir.to_path_buf());
+                }
+                paths_to_invalidate
+              })
+              .flatten()
+              .collect();
+            debug!("notify invalidating {:?} because of {:?}", paths, ev.kind);
+            InvalidationWatcher::invalidate(&graph, &paths, "notify");
+          }
+          Ok(Err(err)) => {
+            if let notify::ErrorKind::PathNotFound = err.kind {
+              warn!("Path(s) did not exist: {:?}", err.paths);
+              continue;
+            } else {
+              error!("File watcher failing with: {}", err);
+              break;
+            }
+          }
+          Err(RecvTimeoutError::Timeout) => continue,
+          Err(RecvTimeoutError::Disconnected) => {
+            // The Watcher is gone: we're done.
+            break;
+          }
+        };
+      }
+      debug!("Watch thread exiting.");
+      // Signal that we're exiting (which we would also do by just dropping the channel).
+      let _ = thread_liveness_sender.send(());
+    });
+
+    Ok(InvalidationWatcher {
+      watcher: wrapped_watcher,
+      executor,
+      liveness: thread_liveness_receiver,
+      current_platform,
+    })
+  }
+
+  ///
+  /// Watch the given path non-recursively.
+  ///
+  pub async fn watch(&self, path: PathBuf) -> Result<(), notify::Error> {
+    // Short circuit here if we are on a Darwin platform because we should be watching
+    // the entire build root recursively already.
+    if self.current_platform == Platform::Darwin {
+      Ok(())
+    } else {
+      // Using a futurized mutex here because for some reason using a regular mutex
+      // to block the io pool causes the v2 ui to not update which nodes its working
+      // on properly.
+      let watcher_lock = self.watcher.lock().compat().await;
+      match watcher_lock {
+        Ok(mut watcher_lock) => {
+          self
+            .executor
+            .spawn_blocking(move || watcher_lock.watch(path, RecursiveMode::NonRecursive))
+            .await
+        }
+        Err(()) => Err(notify::Error::new(notify::ErrorKind::Generic(
+          "Couldn't lock mutex for invalidation watcher".to_string(),
+        ))),
+      }
+    }
+  }
+
+  ///
+  /// Returns true if this InvalidationWatcher is still valid: if it is not valid, it will have
+  /// already logged some sort of error, and will never restart on its own.
+  ///
+  pub fn running(&self) -> bool {
+    match self.liveness.try_recv() {
+      Ok(()) | Err(TryRecvError::Disconnected) => false,
+      Err(TryRecvError::Empty) => true,
+    }
+  }
+
+  pub fn invalidate(graph: &Graph<NodeKey>, paths: &HashSet<PathBuf>, caller: &str) -> usize {
+    let InvalidationResult { cleared, dirtied } = graph.invalidate_from_roots(move |node| {
+      if let Some(fs_subject) = node.fs_subject() {
+        paths.contains(fs_subject)
+      } else {
+        false
+      }
+    });
+    info!(
+      "{} invalidation: cleared {} and dirtied {} nodes for: {:?}",
+      caller, cleared, dirtied, paths
+    );
+    cleared + dirtied
+  }
+}
diff --git a/src/rust/engine/src/watch_tests.rs b/src/rust/engine/src/watch_tests.rs
new file mode 100644
index 00000000000..7b6cb28987e
--- /dev/null
+++ b/src/rust/engine/src/watch_tests.rs
@@ -0,0 +1,66 @@
+use crate::nodes::{DigestFile, NodeKey, NodeResult};
+use crate::watch::InvalidationWatcher;
+use fs::File;
+use graph::entry::{EntryResult, EntryState, Generation, RunToken};
+use graph::{test_support::TestGraph, Graph};
+use hashing::EMPTY_DIGEST;
+use std::path::PathBuf;
+use std::sync::Arc;
+use std::thread::sleep;
+use std::time::Duration;
+use task_executor::Executor;
+use testutil::{append_to_exisiting_file, make_file};
+
+#[test]
+fn receive_watch_event_on_file_change() {
+  env_logger::init();
+  // setup a build_root with a file in it to watch.
+  let build_root = tempfile::TempDir::new().unwrap();
+  let content = "contents".as_bytes().to_vec();
+  let file_path = build_root.path().join("watch_me.txt");
+  make_file(&file_path, &content, 0o600);
+
+  // set up a node in the graph to check that it gets cleared by the invalidation watcher.
+  let node = NodeKey::DigestFile(DigestFile(File {
+    path: PathBuf::from("watch_me.txt"),
+    is_executable: false,
+  }));
+  let graph = Arc::new(Graph::new());
+  let entry_id = graph.add_fixture_entry(node);
+  let completed_state = EntryState::Completed {
+    run_token: RunToken::initial(),
+    generation: Generation::initial(),
+    result: EntryResult::Clean(Ok(NodeResult::Digest(EMPTY_DIGEST))),
+    dep_generations: vec![],
+  };
+  graph.set_fixture_entry_state_for_id(entry_id, completed_state);
+  // Assert the nodes initial state is completed
+  assert!(graph.entry_state(entry_id) == "completed");
+  // Instantiate a watcher and watch the file in question.
+  let mut rt = tokio::runtime::Runtime::new().unwrap();
+  let executor = Executor::new(rt.handle().clone());
+  let watcher = InvalidationWatcher::new(
+    Arc::downgrade(&graph),
+    executor,
+    build_root.path().to_path_buf(),
+  )
+  .expect("Couldn't create InvalidationWatcher");
+  rt.block_on(watcher.watch(file_path.clone())).unwrap();
+  // Update the content of the file being watched.
+  let new_content = "stnetonc".as_bytes().to_vec();
+  append_to_exisiting_file(&file_path, &new_content);
+  // Wait for watcher background thread to trigger a node invalidation,
+  // by checking the entry state for the node. It will be reset to EntryState::NotStarted
+  // when Graph::invalidate_from_roots calls clear on the node.
+  for _ in 0..10 {
+    sleep(Duration::from_millis(100));
+    if graph.entry_state(entry_id) == "not started" {
+      return;
+    }
+  }
+  // If we didn't find a new state fail the test.
+  assert!(
+    false,
+    "Nodes EntryState was not invalidated, or reset to NotStarted."
+  )
+}
diff --git a/src/rust/engine/testutil/src/lib.rs b/src/rust/engine/testutil/src/lib.rs
index 075623877ee..342a5b0c24a 100644
--- a/src/rust/engine/testutil/src/lib.rs
+++ b/src/rust/engine/testutil/src/lib.rs
@@ -53,3 +53,8 @@ pub fn make_file(path: &Path, contents: &[u8], mode: u32) {
   permissions.set_mode(mode);
   file.set_permissions(permissions).unwrap();
 }
+
+pub fn append_to_exisiting_file(path: &Path, contents: &[u8]) {
+  let mut file = std::fs::OpenOptions::new().write(true).open(&path).unwrap();
+  file.write_all(contents).unwrap();
+}
diff --git a/tests/python/pants_test/engine/test_fs.py b/tests/python/pants_test/engine/test_fs.py
index af185438cd0..1fbda3c0ab7 100644
--- a/tests/python/pants_test/engine/test_fs.py
+++ b/tests/python/pants_test/engine/test_fs.py
@@ -4,13 +4,17 @@
 import hashlib
 import logging
 import os
+import shutil
 import tarfile
+import time
 import unittest
 from abc import ABCMeta
 from contextlib import contextmanager
 from http.server import BaseHTTPRequestHandler
 from pathlib import Path
+from typing import Callable
 
+from pants.base.file_system_project_tree import FileSystemProjectTree
 from pants.engine.fs import (
     EMPTY_DIRECTORY_DIGEST,
     Digest,
@@ -55,6 +59,17 @@ def path_globs(globs) -> PathGlobs:
             return globs
         return PathGlobs(globs)
 
+    def read_file_content(self, scheduler, filespecs_or_globs):
+        """Helper method for reading the content of some files from an existing scheduler
+        session."""
+        snapshot = self.execute_expecting_one_result(
+            scheduler, Snapshot, self.path_globs(filespecs_or_globs)
+        ).value
+        result = self.execute_expecting_one_result(
+            scheduler, FilesContent, snapshot.directory_digest
+        ).value
+        return {f.path: f.content for f in result.dependencies}
+
     def assert_walk_dirs(self, filespecs_or_globs, paths, **kwargs):
         self.assert_walk_snapshot("dirs", filespecs_or_globs, paths, **kwargs)
 
@@ -74,13 +89,7 @@ def assert_walk_snapshot(
     def assert_content(self, filespecs_or_globs, expected_content):
         with self.mk_project_tree() as project_tree:
             scheduler = self.mk_scheduler(rules=create_fs_rules(), project_tree=project_tree)
-            snapshot = self.execute_expecting_one_result(
-                scheduler, Snapshot, self.path_globs(filespecs_or_globs)
-            ).value
-            result = self.execute_expecting_one_result(
-                scheduler, FilesContent, snapshot.directory_digest
-            ).value
-            actual_content = {f.path: f.content for f in result.dependencies}
+            actual_content = self.read_file_content(scheduler, filespecs_or_globs)
             self.assertEqual(expected_content, actual_content)
 
     def assert_digest(self, filespecs_or_globs, expected_files):
@@ -134,7 +143,7 @@ def test_walk_parent_link(self):
 
     def test_walk_escaping_symlink(self):
         link = "subdir/escaping"
-        dest = "../../this-is-probably-nonexistent"
+        dest = "../../"
 
         def prepare(project_tree):
             link_path = os.path.join(project_tree.build_root, link)
@@ -708,6 +717,111 @@ def test_nonexistent_filename_globs(self) -> None:
         subset_digest = self.request_single_product(Digest, subset_input)
         assert subset_snapshot.directory_digest == subset_digest
 
+    def test_file_content_invalidated(self) -> None:
+        """Test that we can update files and have the native engine invalidate previous operations
+        on those files."""
+
+        with self.mk_project_tree() as project_tree:
+            scheduler = self.mk_scheduler(rules=create_fs_rules(), project_tree=project_tree)
+            fname = "4.txt"
+            new_data = "rouf"
+            # read the original file so we have a cached value.
+            self.read_file_content(scheduler, [fname])
+            path_to_fname = os.path.join(project_tree.build_root, fname)
+            with open(path_to_fname, "w") as f:
+                f.write(new_data)
+
+            def assertion_fn():
+                new_content = self.read_file_content(scheduler, [fname])
+                if new_content[fname].decode("utf-8") == new_data:
+                    # successfully read new data
+                    return True
+                return False
+
+            if not self.try_with_backoff(assertion_fn):
+                raise AssertionError(
+                    f"New content {new_data} was not found in the FilesContent of the "
+                    "modified file {path_to_fname}, instead we found {new_content[fname]}"
+                )
+
+    def test_file_content_invalidated_after_parent_deletion(self) -> None:
+        """Test that FileContent is invalidated after deleting parent directory."""
+
+        with self.mk_project_tree() as project_tree:
+            scheduler = self.mk_scheduler(rules=create_fs_rules(), project_tree=project_tree)
+            fname = "a/b/1.txt"
+            # read the original file so we have nodes to invalidate.
+            original_content = self.read_file_content(scheduler, [fname])
+            self.assertIn(fname, original_content)
+            path_to_parent_dir = os.path.join(project_tree.build_root, "a/b/")
+            shutil.rmtree(path_to_parent_dir)
+
+            def assertion_fn():
+                new_content = self.read_file_content(scheduler, [fname])
+                if new_content.get(fname) is None:
+                    return True
+                return False
+
+            if not self.try_with_backoff(assertion_fn):
+                raise AssertionError(
+                    f"Deleting parent dir and could still read file from original snapshot."
+                )
+
+    def assert_mutated_directory_digest(
+        self, mutation_function: Callable[[FileSystemProjectTree, str], Exception]
+    ):
+        with self.mk_project_tree() as project_tree:
+            scheduler = self.mk_scheduler(rules=create_fs_rules(), project_tree=project_tree)
+            dir_path = "a/"
+            dir_glob = dir_path + "*"
+            initial_snapshot = self.execute_expecting_one_result(
+                scheduler, Snapshot, self.path_globs([dir_glob])
+            ).value
+            assert not initial_snapshot.is_empty
+            assertion_error = mutation_function(project_tree, dir_path)
+
+            def assertion_fn():
+                new_snapshot = self.execute_expecting_one_result(
+                    scheduler, Snapshot, self.path_globs([dir_glob])
+                ).value
+                assert not new_snapshot.is_empty
+                if initial_snapshot.directory_digest != new_snapshot.directory_digest:
+                    # successfully invalidated snapshot and got a new digest
+                    return True
+                return False
+
+            if not self.try_with_backoff(assertion_fn):
+                raise assertion_error
+
+    @staticmethod
+    def try_with_backoff(assertion_fn: Callable[[], bool]) -> bool:
+        for i in range(4):
+            time.sleep(0.1 * i)
+            if assertion_fn():
+                return True
+        return False
+
+    def test_directory_digest_invalidated_by_child_removal(self):
+        def mutation_function(project_tree, dir_path):
+            removed_path = os.path.join(project_tree.build_root, dir_path, "3.txt")
+            os.remove(removed_path)
+            return AssertionError(
+                f"Did not find a new directory snapshot after adding file {removed_path}."
+            )
+
+        self.assert_mutated_directory_digest(mutation_function)
+
+    def test_directory_digest_invalidated_by_child_change(self):
+        def mutation_function(project_tree, dir_path):
+            new_file_path = os.path.join(project_tree.build_root, dir_path, "new_file.txt")
+            with open(new_file_path, "w") as f:
+                f.write("new file")
+            return AssertionError(
+                f"Did not find a new directory snapshot after adding file {new_file_path}."
+            )
+
+        self.assert_mutated_directory_digest(mutation_function)
+
 
 class StubHandler(BaseHTTPRequestHandler):
     response_text = b"www.pantsbuild.org"