Auto merge of #11381 - ehuss:beta-fix-safe-directory, r=weihanglo

[beta-1.66] Backport fix for git2 safe-directory disable

Beta backports:

* #11366 — fix git2 safe-directory disable
* #11332 — fix semver documentation for change in non_exhaustive
* #11335 — Clean more aggressively in CI

Author: bors

.github/workflows/main.yml

@@ -80,6 +80,13 @@ jobs:
 
     # Deny warnings on CI to avoid warnings getting into the codebase.
     - run: cargo test --features 'deny-warnings'
+    # The testsuite generates a huge amount of data, and fetch-smoke-test was
+    # running out of disk space.
+    - name: Clear test output
+      run: |
+        df -h
+        rm -rf target/tmp
+        df -h
     - name: Check operability of rustc invocation with argfile
       env:
         __CARGO_TEST_FORCE_ARGFILE: 1
@@ -111,7 +118,7 @@ jobs:
         cargo check --manifest-path benches/capture/Cargo.toml
     # The testsuite generates a huge amount of data, and fetch-smoke-test was
     # running out of disk space.
-    - name: Clear test output
+    - name: Clear benchmark output
       run: |
         df -h
         rm -rf target/tmp

src/bin/cargo/cli.rs

@@ -149,7 +149,7 @@ Run with 'cargo -Z [FLAG] [COMMAND]'",
         }
     };
     config_configure(config, &expanded_args, subcommand_args, global_args)?;
-    super::init_git_transports(config);
+    super::init_git(config);
 
     execute_subcommand(config, cmd, subcommand_args)
 }

src/bin/cargo/main.rs

@@ -246,6 +246,38 @@ fn search_directories(config: &Config) -> Vec<PathBuf> {
     path_dirs
 }
 
+/// Initialize libgit2.
+fn init_git(config: &Config) {
+    // Disabling the owner validation in git can, in theory, lead to code execution
+    // vulnerabilities. However, libgit2 does not launch executables, which is the foundation of
+    // the original security issue. Meanwhile, issues with refusing to load git repos in
+    // `CARGO_HOME` for example will likely be very frustrating for users. So, we disable the
+    // validation.
+    //
+    // For further discussion of Cargo's current interactions with git, see
+    //
+    //   https://github.com/rust-lang/rfcs/pull/3279
+    //
+    // and in particular the subsection on "Git support".
+    //
+    // Note that we only disable this when Cargo is run as a binary. If Cargo is used as a library,
+    // this code won't be invoked. Instead, developers will need to explicitly disable the
+    // validation in their code. This is inconvenient, but won't accidentally open consuming
+    // applications up to security issues if they use git2 to open repositories elsewhere in their
+    // code.
+    unsafe {
+        git2::opts::set_verify_owner_validation(false)
+            .expect("set_verify_owner_validation should never fail");
+    }
+
+    init_git_transports(config);
+}
+
+/// Configure libgit2 to use libcurl if necessary.
+///
+/// If the user has a non-default network configuration, then libgit2 will be
+/// configured to use libcurl instead of the built-in networking support so
+/// that those configuration settings can be used.
 fn init_git_transports(config: &Config) {
     // Only use a custom transport if any HTTP options are specified,
     // such as proxies or custom certificate authorities. The custom
@@ -274,27 +306,4 @@ fn init_git_transports(config: &Config) {
     unsafe {
         git2_curl::register(handle);
     }
-
-    // Disabling the owner validation in git can, in theory, lead to code execution
-    // vulnerabilities. However, libgit2 does not launch executables, which is the foundation of
-    // the original security issue. Meanwhile, issues with refusing to load git repos in
-    // `CARGO_HOME` for example will likely be very frustrating for users. So, we disable the
-    // validation.
-    //
-    // For further discussion of Cargo's current interactions with git, see
-    //
-    //   https://github.com/rust-lang/rfcs/pull/3279
-    //
-    // and in particular the subsection on "Git support".
-    //
-    // Note that we only disable this when Cargo is run as a binary. If Cargo is used as a library,
-    // this code won't be invoked. Instead, developers will need to explicitly disable the
-    // validation in their code. This is inconvenient, but won't accidentally open consuming
-    // applications up to security issues if they use git2 to open repositories elsewhere in their
-    // code.
-    unsafe {
-        if git2::opts::set_verify_owner_validation(false).is_err() {
-            return;
-        }
-    }
 }

src/doc/src/reference/semver.md

@@ -391,7 +391,7 @@ pub enum E {
 fn main() {
     use updated_crate::E;
     let x = E::Variant1;
-    match x { // Error: `Variant2` not covered
+    match x { // Error: `E::Variant2` not covered
         E::Variant1 => {}
     }
 }