test(trim-paths): re-enable lldb debugger tests

.github/workflows/main.yml

@@ -132,6 +132,7 @@ jobs:
       CARGO_PROFILE_TEST_DEBUG: 1
       CARGO_INCREMENTAL: 0
       CARGO_PUBLIC_NETWORK_TESTS: 1
+      CARGO_TEST_REQUIRE_EXTERNAL_TOOLS: 1
       # Workaround for https://github.com/rust-lang/rustup/issues/3036
       RUSTUP_WINDOWS_PATH_ADD_BIN: 0
     strategy:
@@ -168,22 +169,27 @@ jobs:
         - name: Windows x86_64 MSVC stable
           os: windows-latest
           rust: stable-msvc
+          target_env: msvc
           other: i686-pc-windows-msvc
         - name: Windows x86_64 MSVC nightly
           os: windows-latest
           rust: nightly-msvc
+          target_env: msvc
           other: i686-pc-windows-msvc
         - name: Windows aarch64 MSVC stable
           os: windows-11-arm
           rust: stable-msvc
+          target_env: msvc
           other: i686-pc-windows-msvc
         - name: Windows aarch64 MSVC nightly
           os: windows-11-arm
           rust: nightly-msvc
+          target_env: msvc
           other: i686-pc-windows-msvc
         - name: Windows x86_64 gnu nightly # runs out of space while trying to link the test suite
           os: windows-latest
           rust: nightly-gnu
+          target_env: gnu
           other: i686-pc-windows-gnu
     name: Tests ${{ matrix.name }}
     steps:
@@ -204,6 +210,12 @@ jobs:
       if: startsWith(matrix.rust, 'nightly')
     - run: sudo apt update -y && sudo apt install lldb gcc-multilib libsecret-1-0 libsecret-1-dev -y
       if: matrix.os == 'ubuntu-latest'
+    - name: Install LLDB on Linux ARM
+      run: sudo apt update -y && sudo apt install lldb -y
+      if: matrix.os == 'ubuntu-24.04-arm'
+    - name: Check LLDB debugger tool
+      run: lldb --version
+      if: runner.os != 'Windows'
     - run: rustup component add rustfmt || echo "rustfmt not available"
     - name: Add Windows debuggers bin to PATH
       shell: pwsh
@@ -215,13 +227,13 @@ jobs:
       if: matrix.os == 'windows-11-arm'
     - name: Check Windows MSVC debugger tool
       run: cdb -version
-      if: matrix.rust == 'nightly-msvc'
+      if: runner.os == 'Windows' && matrix.target_env == 'msvc'
     - name: Check Windows GNU object tool
       run: objdump --version
-      if: matrix.os == 'windows-latest' && matrix.rust == 'nightly-gnu'
+      if: runner.os == 'Windows' && matrix.target_env == 'gnu'
     - name: Check Windows GNU debugger tool
       run: gdb --version
-      if: matrix.os == 'windows-latest' && matrix.rust == 'nightly-gnu'
+      if: runner.os == 'Windows' && matrix.target_env == 'gnu'
     - name: Configure extra test environment
       run: echo CARGO_CONTAINER_TESTS=1 >> $GITHUB_ENV
       if: matrix.os == 'ubuntu-latest'

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

@@ -36,7 +36,8 @@ use std::sync::LazyLock;
 ///   A `reason` field is required to explain why it is nightly-only.
 /// * `requires = "<cmd>"` --- This indicates a command that is required to be installed to be run.
 ///   For example, `requires = "rustfmt"` means the test will only run if the executable `rustfmt` is installed.
-///   These tests are *always* run on CI.
+///   These tests are run in Cargo's CI when CARGO_TEST_REQUIRE_EXTERNAL_TOOLS is set.
+///   Other environments, including rust-lang/rust's CI, ignore the test when the command is unavailable.
 ///   This is mainly used to avoid requiring contributors from having every dependency installed.
 /// * `requires_host_split_debuginfo = "<value>"` --- This indicates a `-Csplit-debuginfo` value
 ///   that is required to be supported by the host `rustc`.
@@ -374,11 +375,7 @@ fn check_command(command_path: &Path, args: &[&str]) -> bool {
     let output = match command.output() {
         Ok(output) => output,
         Err(e) => {
-            // * hg is not installed on GitHub macOS or certain constrained
-            //   environments like Docker. Consider installing it if Cargo
-            //   gains more hg support, but otherwise it isn't critical.
-            // * lldb is not pre-installed on Ubuntu and Windows, so skip.
-            if is_ci() && !matches!(command_name.as_str(), "hg" | "lldb") {
+            if is_ci() {
                 panic!("expected command `{command_name}` to be somewhere in PATH: {e}",);
             }
             return false;
@@ -404,7 +401,7 @@ fn has_command(command: &str) -> bool {
     let Some(paths) = std::env::var_os("PATH") else {
         return false;
     };
-    std::env::split_paths(&paths)
+    let found = std::env::split_paths(&paths)
         .flat_map(|path| {
             let candidate = path.join(&command);
             let with_exe = if EXE_EXTENSION.is_empty() {
@@ -415,7 +412,14 @@ fn has_command(command: &str) -> bool {
             std::iter::once(candidate).chain(with_exe)
         })
         .find(|p| is_executable(p))
-        .is_some()
+        .is_some();
+    // * hg is not installed on GitHub macOS or certain constrained
+    //   environments like Docker. Consider installing it if Cargo
+    //   gains more hg support, but otherwise it isn't critical.
+    if !found && requires_external_tools() && command != "hg" {
+        panic!("expected command `{command}` to be somewhere in PATH");
+    }
+    found
 }
 
 #[cfg(unix)]
@@ -455,3 +459,8 @@ fn is_ci() -> bool {
     // itself like option_env does.
     option_env!("CI").is_some() || option_env!("TF_BUILD").is_some()
 }
+
+/// Whether to enforce external tools (`requires=<tool>`) availability.
+fn requires_external_tools() -> bool {
+    option_env!("CARGO_TEST_REQUIRE_EXTERNAL_TOOLS").is_some()
+}

src/cargo/core/compiler/mod.rs

@@ -1541,9 +1541,6 @@ fn trim_paths_args_rustdoc(
         _ => {}
     }
 
-    // feature gate was checked during manifest/config parsing.
-    cmd.arg("-Zunstable-options");
-
     for pair in trim_paths_remap(build_runner, unit) {
         let mut arg = OsString::from("--remap-path-prefix=");
         arg.push(pair);