Auto merge of #7776 - alexcrichton:anyhow, r=ehuss

Migrate from the `failure` crate to `anyhow`

The `anyhow` crate interoperates with the `std::error::Error` trait
rather than a custom `Fail` trait, and this is the general trend of
error handling in Rust as well.

Note that this is mostly mechanical (sed) and intended to get the test
suite passing. As usual there's still more idiomatic cleanup that can
happen, but that's left to later commits.

Cargo.toml

@@ -29,7 +29,7 @@ curl = { version = "0.4.23", features = ["http2"] }
 curl-sys = "0.4.22"
 env_logger = "0.7.0"
 pretty_env_logger = { version = "0.3", optional = true }
-failure = "0.1.5"
+anyhow = "1.0"
 filetime = "0.2"
 flate2 = { version = "1.0.3", features = ["zlib"] }
 fs2 = "0.4"
@@ -51,7 +51,7 @@ num_cpus = "1.0"
 opener = "0.4"
 percent-encoding = "2.0"
 remove_dir_all = "0.5.2"
-rustfix = "0.4.6"
+rustfix = "0.5.0"
 same-file = "1"
 semver = { version = "0.9.0", features = ["serde"] }
 serde = { version = "1.0.82", features = ["derive"] }

crates/cargo-test-support/src/lib.rs

@@ -916,11 +916,7 @@ impl Execs {
                 {
                     return self.match_output(out);
                 }
-                let mut s = format!("could not exec process {}: {}", process, e);
-                for cause in e.iter_causes() {
-                    s.push_str(&format!("\ncaused by: {}", cause));
-                }
-                Err(s)
+                Err(format!("could not exec process {}: {:?}", process, e))
             }
         }
     }

crates/crates-io/Cargo.toml

@@ -15,7 +15,7 @@ path = "lib.rs"
 
 [dependencies]
 curl = "0.4"
-failure = "0.1.1"
+anyhow = "1.0.0"
 percent-encoding = "2.0"
 serde = { version = "1.0", features = ['derive'] }
 serde_derive = "1.0"

crates/crates-io/lib.rs

@@ -7,15 +7,13 @@ use std::io::prelude::*;
 use std::io::Cursor;
 use std::time::Instant;
 
+use anyhow::{bail, Result};
 use curl::easy::{Easy, List};
-use failure::bail;
 use percent_encoding::{percent_encode, NON_ALPHANUMERIC};
 use serde::{Deserialize, Serialize};
 use serde_json;
 use url::Url;
 
-pub type Result<T> = std::result::Result<T, failure::Error>;
-
 pub struct Registry {
     /// The base URL for issuing API requests.
     host: String,

src/bin/cargo/commands/bench.rs

@@ -100,7 +100,7 @@ pub fn exec(config: &mut Config, args: &ArgMatches<'_>) -> CliResult {
     match err {
         None => Ok(()),
         Some(err) => Err(match err.exit.as_ref().and_then(|e| e.code()) {
-            Some(i) => CliError::new(failure::format_err!("bench failed"), i),
+            Some(i) => CliError::new(anyhow::format_err!("bench failed"), i),
             None => CliError::new(err.into(), 101),
         }),
     }

src/bin/cargo/commands/check.rs

@@ -60,7 +60,7 @@ pub fn exec(config: &mut Config, args: &ArgMatches<'_>) -> CliResult {
         Some("test") => true,
         None => false,
         Some(profile) => {
-            let err = failure::format_err!(
+            let err = anyhow::format_err!(
                 "unknown profile: `{}`, only `test` is \
                  currently supported",
                 profile

src/bin/cargo/commands/clippy.rs

@@ -66,7 +66,7 @@ pub fn exec(config: &mut Config, args: &ArgMatches<'_>) -> CliResult {
         args.compile_options(config, mode, Some(&ws), ProfileChecking::Checked)?;
 
     if !config.cli_unstable().unstable_options {
-        return Err(failure::format_err!(
+        return Err(anyhow::format_err!(
             "`clippy-preview` is unstable, pass `-Z unstable-options` to enable it"
         )
         .into());

src/bin/cargo/commands/fix.rs

@@ -120,7 +120,7 @@ pub fn exec(config: &mut Config, args: &ArgMatches<'_>) -> CliResult {
         Some("test") => true,
         None => false,
         Some(profile) => {
-            let err = failure::format_err!(
+            let err = anyhow::format_err!(
                 "unknown profile: `{}`, only `test` is \
                  currently supported",
                 profile
@@ -143,7 +143,7 @@ pub fn exec(config: &mut Config, args: &ArgMatches<'_>) -> CliResult {
         .filter(|_| use_clippy);
 
     if use_clippy && !config.cli_unstable().unstable_options {
-        return Err(failure::format_err!(
+        return Err(anyhow::format_err!(
             "`cargo fix --clippy` is unstable, pass `-Z unstable-options` to enable it"
         )
         .into());

src/bin/cargo/commands/locate_project.rs

@@ -21,7 +21,7 @@ pub fn exec(config: &mut Config, args: &ArgMatches<'_>) -> CliResult {
     let root = root
         .to_str()
         .ok_or_else(|| {
-            failure::format_err!(
+            anyhow::format_err!(
                 "your package path contains characters \
                  not representable in Unicode"
             )

src/bin/cargo/commands/rustc.rs

@@ -55,7 +55,7 @@ pub fn exec(config: &mut Config, args: &ArgMatches<'_>) -> CliResult {
         Some("bench") => CompileMode::Bench,
         Some("check") => CompileMode::Check { test: false },
         Some(mode) => {
-            let err = failure::format_err!(
+            let err = anyhow::format_err!(
                 "unknown profile: `{}`, use dev,
                                    test, or bench",
                 mode

src/bin/cargo/commands/test.rs

@@ -1,7 +1,7 @@
 use crate::command_prelude::*;
+use anyhow::Error;
 use cargo::ops::{self, CompileFilter, FilterRule, LibRule};
 use cargo::util::errors;
-use failure::Fail;
 
 pub fn cli() -> App {
     subcommand("test")
@@ -126,13 +126,13 @@ pub fn exec(config: &mut Config, args: &ArgMatches<'_>) -> CliResult {
     if doc {
         if let CompileFilter::Only { .. } = compile_opts.filter {
             return Err(CliError::new(
-                failure::format_err!("Can't mix --doc with other target selecting options"),
+                anyhow::format_err!("Can't mix --doc with other target selecting options"),
                 101,
             ));
         }
         if no_run {
             return Err(CliError::new(
-                failure::format_err!("Can't skip running doc tests with --no-run"),
+                anyhow::format_err!("Can't skip running doc tests with --no-run"),
                 101,
             ));
         }
@@ -166,12 +166,12 @@ pub fn exec(config: &mut Config, args: &ArgMatches<'_>) -> CliResult {
     match err {
         None => Ok(()),
         Some(err) => {
-            let context = failure::format_err!("{}", err.hint(&ws, &ops.compile_opts));
+            let context = anyhow::format_err!("{}", err.hint(&ws, &ops.compile_opts));
             let e = match err.exit.as_ref().and_then(|e| e.code()) {
                 // Don't show "process didn't exit successfully" for simple errors.
                 Some(i) if errors::is_simple_exit_code(i) => CliError::new(context, i),
-                Some(i) => CliError::new(err.context(context).into(), i),
-                None => CliError::new(err.context(context).into(), 101),
+                Some(i) => CliError::new(Error::from(err).context(context), i),
+                None => CliError::new(Error::from(err).context(context), 101),
             };
             Err(e)
         }

src/bin/cargo/commands/vendor.rs

@@ -90,7 +90,7 @@ pub fn exec(config: &mut Config, args: &ArgMatches<'_>) -> CliResult {
         None
     };
     if let Some(flag) = crates_io_cargo_vendor_flag {
-        return Err(failure::format_err!(
+        return Err(anyhow::format_err!(
             "\
 the crates.io `cargo vendor` command has now been merged into Cargo itself
 and does not support the flag `{}` currently; to continue using the flag you

src/bin/cargo/main.rs

@@ -133,7 +133,7 @@ fn execute_external_subcommand(config: &Config, cmd: &str, args: &[&str]) -> Cli
             let aliases = list_aliases(config);
             let suggestions = commands.iter().chain(aliases.iter());
             let did_you_mean = closest_msg(cmd, suggestions, |c| c);
-            let err = failure::format_err!("no such subcommand: `{}`{}", cmd, did_you_mean);
+            let err = anyhow::format_err!("no such subcommand: `{}`{}", cmd, did_you_mean);
             return Err(CliError::new(err, 101));
         }
     };

src/cargo/core/compiler/build_config.rs

@@ -78,7 +78,7 @@ impl BuildConfig {
         };
 
         if jobs == Some(0) {
-            failure::bail!("jobs must be at least 1")
+            anyhow::bail!("jobs must be at least 1")
         }
         if jobs.is_some() && config.jobserver_from_env().is_some() {
             config.shell().warn(

src/cargo/core/compiler/build_context/target_info.rs

@@ -137,7 +137,7 @@ impl TargetInfo {
 
         let line = match lines.next() {
             Some(line) => line,
-            None => failure::bail!(
+            None => anyhow::bail!(
                 "output of --print=sysroot missing when learning about \
                  target-specific information from rustc\n{}",
                 output_err_info(&process, &output, &error)
@@ -329,7 +329,7 @@ fn parse_crate_type(
     }
     let line = match lines.next() {
         Some(line) => line,
-        None => failure::bail!(
+        None => anyhow::bail!(
             "malformed output when learning about crate-type {} information\n{}",
             crate_type,
             output_err_info(cmd, output, error)
@@ -339,7 +339,7 @@ fn parse_crate_type(
     let prefix = parts.next().unwrap();
     let suffix = match parts.next() {
         Some(part) => part,
-        None => failure::bail!(
+        None => anyhow::bail!(
             "output of --print=file-names has changed in the compiler, cannot parse\n{}",
             output_err_info(cmd, output, error)
         ),

src/cargo/core/compiler/build_plan.rs

@@ -74,13 +74,13 @@ impl Invocation {
         self.program = cmd
             .get_program()
             .to_str()
-            .ok_or_else(|| failure::format_err!("unicode program string required"))?
+            .ok_or_else(|| anyhow::format_err!("unicode program string required"))?
             .to_string();
         self.cwd = Some(cmd.get_cwd().unwrap().to_path_buf());
         for arg in cmd.get_args().iter() {
             self.args.push(
                 arg.to_str()
-                    .ok_or_else(|| failure::format_err!("unicode argument string required"))?
+                    .ok_or_else(|| anyhow::format_err!("unicode argument string required"))?
                     .to_string(),
             );
         }
@@ -93,7 +93,7 @@ impl Invocation {
                 var.clone(),
                 value
                     .to_str()
-                    .ok_or_else(|| failure::format_err!("unicode environment value required"))?
+                    .ok_or_else(|| anyhow::format_err!("unicode environment value required"))?
                     .to_string(),
             );
         }

src/cargo/core/compiler/compilation.rs

@@ -304,7 +304,7 @@ fn target_runner(
         .filter(|(key, _runner)| CfgExpr::matches_key(key, target_cfg));
     let matching_runner = cfgs.next();
     if let Some((key, runner)) = cfgs.next() {
-        failure::bail!(
+        anyhow::bail!(
             "several matching instances of `target.'cfg(..)'.runner` in `.cargo/config`\n\
              first match `{}` located in {}\n\
              second match `{}` located in {}",

src/cargo/core/compiler/compile_kind.rs

@@ -77,7 +77,7 @@ impl CompileTarget {
     pub fn new(name: &str) -> CargoResult<CompileTarget> {
         let name = name.trim();
         if name.is_empty() {
-            failure::bail!("target was empty");
+            anyhow::bail!("target was empty");
         }
         if !name.ends_with(".json") {
             return Ok(CompileTarget { name: name.into() });
@@ -88,12 +88,12 @@ impl CompileTarget {
         // with different paths always produce the same result.
         let path = Path::new(name)
             .canonicalize()
-            .chain_err(|| failure::format_err!("target path {:?} is not a valid file", name))?;
+            .chain_err(|| anyhow::format_err!("target path {:?} is not a valid file", name))?;
 
         let name = path
             .into_os_string()
             .into_string()
-            .map_err(|_| failure::format_err!("target path is not valid unicode"))?;
+            .map_err(|_| anyhow::format_err!("target path is not valid unicode"))?;
         Ok(CompileTarget { name: name.into() })
     }
 

src/cargo/core/compiler/context/compilation_files.rs

@@ -431,15 +431,15 @@ impl<'a, 'cfg: 'a> CompilationFiles<'a, 'cfg> {
         }
         if ret.is_empty() {
             if !unsupported.is_empty() {
-                failure::bail!(
+                anyhow::bail!(
                     "cannot produce {} for `{}` as the target `{}` \
                      does not support these crate types",
                     unsupported.join(", "),
                     unit.pkg,
                     unit.kind.short_name(bcx),
                 )
             }
-            failure::bail!(
+            anyhow::bail!(
                 "cannot compile `{}` as the target `{}` does not \
                  support any of the output crate types",
                 unit.pkg,

src/cargo/core/compiler/custom_build.rs

@@ -460,7 +460,7 @@ impl BuildOutput {
             let (key, value) = match (key, value) {
                 (Some(a), Some(b)) => (a, b.trim_end()),
                 // Line started with `cargo:` but didn't match `key=value`.
-                _ => failure::bail!("Wrong output in {}: `{}`", whence, line),
+                _ => anyhow::bail!("Wrong output in {}: `{}`", whence, line),
             };
 
             // This will rewrite paths if the target directory has been moved.
@@ -520,7 +520,7 @@ impl BuildOutput {
                 if value.is_empty() {
                     value = match flags_iter.next() {
                         Some(v) => v,
-                        None => failure::bail! {
+                        None => anyhow::bail! {
                             "Flag in rustc-flags has no value in {}: {}",
                             whence,
                             value
@@ -536,7 +536,7 @@ impl BuildOutput {
                     _ => unreachable!(),
                 };
             } else {
-                failure::bail!(
+                anyhow::bail!(
                     "Only `-l` and `-L` flags are allowed in {}: `{}`",
                     whence,
                     value
@@ -552,7 +552,7 @@ impl BuildOutput {
         let val = iter.next();
         match (name, val) {
             (Some(n), Some(v)) => Ok((n.to_owned(), v.to_owned())),
-            _ => failure::bail!("Variable rustc-env has no value in {}: {}", whence, value),
+            _ => anyhow::bail!("Variable rustc-env has no value in {}: {}", whence, value),
         }
     }
 }

src/cargo/core/compiler/fingerprint.rs

@@ -194,7 +194,7 @@ use std::path::{Path, PathBuf};
 use std::sync::{Arc, Mutex};
 use std::time::SystemTime;
 
-use failure::{bail, format_err};
+use anyhow::{bail, format_err};
 use filetime::FileTime;
 use log::{debug, info};
 use serde::de;
@@ -1414,11 +1414,7 @@ fn log_compare(unit: &Unit<'_>, compare: &CargoResult<()>) {
         "fingerprint error for {}/{:?}/{:?}",
         unit.pkg, unit.mode, unit.target,
     );
-    info!("    err: {}", ce);
-
-    for cause in ce.iter_causes() {
-        info!("  cause: {}", cause);
-    }
+    info!("    err: {:?}", ce);
 }
 
 // Parse the dep-info into a list of paths

src/cargo/core/compiler/job_queue.rs

@@ -7,8 +7,8 @@ use std::sync::mpsc::{channel, Receiver, Sender};
 use std::sync::Arc;
 use std::time::Duration;
 
+use anyhow::format_err;
 use crossbeam_utils::thread::Scope;
-use failure::format_err;
 use jobserver::{Acquired, HelperThread};
 use log::{debug, info, trace};
 
@@ -393,7 +393,7 @@ impl<'a, 'cfg> JobQueue<'a, 'cfg> {
                                 self.emit_warnings(Some(msg), &unit, cx)?;
 
                                 if !self.active.is_empty() {
-                                    error = Some(failure::format_err!("build failed"));
+                                    error = Some(anyhow::format_err!("build failed"));
                                     handle_error(&e, &mut *cx.bcx.config.shell());
                                     cx.bcx.config.shell().warn(
                                         "build failed, waiting for other \

src/cargo/core/compiler/links.rs

@@ -39,7 +39,7 @@ pub fn validate_links(resolve: &Resolve, unit_graph: &UnitGraph<'_>) -> CargoRes
                 dep_path_desc
             };
 
-            failure::bail!(
+            anyhow::bail!(
                 "multiple packages link to native library `{}`, \
                  but a native library can be linked only once\n\
                  \n\

src/cargo/core/compiler/mod.rs

@@ -23,7 +23,7 @@ use std::io::{BufRead, Write};
 use std::path::PathBuf;
 use std::sync::Arc;
 
-use failure::Error;
+use anyhow::Error;
 use lazycell::LazyCell;
 use log::debug;