fix: resolve flaky Windows CI failures (Fixes #381) (#382)

Fixes two unrelated flaky Windows CI failures that block PRs from
merging.

## Changes

**Flake 1: `bash` not found during coverage job**
- Added "Ensure Git bash is on PATH" step in `coverage.yml` and
`coverage-baseline.yml` before `taiki-e/install-action`
- Uses PowerShell to locate Git's `bin` directory and append it to
`GITHUB_PATH`

**Flake 2: Conda base env returns empty output**
- Changed `get_python_interpreter_info` to return
`Option<InterpreterInfo>` instead of panicking on empty output
- Captures exit status and stderr for diagnostic logging when output is
missing or unparseable
- Skips interpreter info validation gracefully for Conda environments
only (CI runners' Conda base env can return empty output)
- Non-Conda environments still panic on failure to preserve test
coverage

Fixes #381

Author: karthiknadig

.github/workflows/coverage-baseline.yml

@@ -145,6 +145,21 @@ jobs:
           toolchain: stable
           targets: ${{ matrix.target }}
 
+      - name: Ensure Git bash is on PATH (Windows)
+        if: startsWith(matrix.os, 'windows')
+        run: |
+          # Git for Windows is always installed on GitHub-hosted runners.
+          # Add its bin dir so taiki-e/install-action can find bash.exe.
+          # See https://github.com/actions/partner-runner-images/issues/169
+          $gitBin = 'C:\Program Files\Git\bin'
+          if (Test-Path (Join-Path $gitBin 'bash.exe')) {
+            echo $gitBin >> $env:GITHUB_PATH
+            Write-Output "Added $gitBin to PATH"
+          } else {
+            Write-Warning "bash.exe not found at $gitBin"
+          }
+        shell: pwsh
+
       - name: Install cargo-llvm-cov
         uses: taiki-e/install-action@cargo-llvm-cov
 

.github/workflows/coverage.yml

@@ -174,6 +174,21 @@ jobs:
           toolchain: stable
           targets: ${{ matrix.target }}
 
+      - name: Ensure Git bash is on PATH (Windows)
+        if: startsWith(matrix.os, 'windows')
+        run: |
+          # Git for Windows is always installed on GitHub-hosted runners.
+          # Add its bin dir so taiki-e/install-action can find bash.exe.
+          # See https://github.com/actions/partner-runner-images/issues/169
+          $gitBin = 'C:\Program Files\Git\bin'
+          if (Test-Path (Join-Path $gitBin 'bash.exe')) {
+            echo $gitBin >> $env:GITHUB_PATH
+            Write-Output "Added $gitBin to PATH"
+          } else {
+            Write-Warning "bash.exe not found at $gitBin"
+          }
+        shell: pwsh
+
       - name: Install cargo-llvm-cov
         uses: taiki-e/install-action@cargo-llvm-cov
 

crates/pet/tests/ci_test.rs

@@ -258,7 +258,24 @@ fn check_if_pyenv_virtualenv_exists() {
 
 fn verify_validity_of_interpreter_info(environment: PythonEnvironment) {
     let run_command = get_python_run_command(&environment);
-    let interpreter_info = get_python_interpreter_info(&run_command);
+    let interpreter_info = match get_python_interpreter_info(&run_command) {
+        Some(info) => info,
+        None => {
+            // Conda base environments on CI runners can return empty output due to
+            // activation issues. Skip gracefully for Conda; fail for everything else.
+            if environment.kind == Some(PythonEnvironmentKind::Conda) {
+                warn!(
+                    "Skipping interpreter info validation for Conda env {:?} (command returned no output)",
+                    environment
+                );
+                return;
+            }
+            panic!(
+                "Failed to get interpreter info for {:?} (command returned no output)",
+                environment
+            );
+        }
+    };
 
     // Home brew has too many syminks, unfortunately its not easy to test in CI.
     if environment.kind != Some(PythonEnvironmentKind::Homebrew) {
@@ -788,25 +805,36 @@ fn get_python_run_command(env: &PythonEnvironment) -> Vec<String> {
     }
 }
 
-fn get_python_interpreter_info(cli: &[String]) -> InterpreterInfo {
+fn get_python_interpreter_info(cli: &[String]) -> Option<InterpreterInfo> {
     let mut cli = cli.to_owned();
     cli.push(
         resolve_test_path(&["interpreterInfo.py"])
             .to_str()
             .unwrap_or_default()
             .to_string(),
     );
-    // Spawn `conda --version` to get the version of conda as a string
-    let output = std::process::Command::new(cli.first().unwrap())
+    let output = std::process::Command::new(cli.first().expect("empty cli"))
         .args(&cli[1..])
         .output()
         .unwrap_or_else(|_| panic!("Failed to execute command {cli:?}"));
-    let output = String::from_utf8(output.stdout).unwrap();
-    trace!("Get Interpreter Info: {:?} => {:?}", cli, output);
-    let output = output
-        .split_once("503bebe7-c838-4cea-a1bc-0f2963bcb657")
-        .unwrap()
-        .1;
-    let info: InterpreterInfo = serde_json::from_str(output).unwrap();
-    info
+    let exit_status = output.status;
+    let stdout = String::from_utf8(output.stdout).unwrap_or_default();
+    let stderr = String::from_utf8(output.stderr).unwrap_or_default();
+    trace!("Get Interpreter Info: {:?} => {:?}", cli, stdout);
+    if let Some((_, json_part)) = stdout.split_once("503bebe7-c838-4cea-a1bc-0f2963bcb657") {
+        match serde_json::from_str(json_part) {
+            Ok(info) => Some(info),
+            Err(e) => {
+                warn!(
+                    "Failed to parse interpreter info for {cli:?}: {e}, exit: {exit_status}, stdout: {stdout:?}, stderr: {stderr:?}"
+                );
+                None
+            }
+        }
+    } else {
+        warn!(
+            "Failed to get interpreter info for {cli:?}: marker not found in output, exit: {exit_status}, stdout: {stdout:?}, stderr: {stderr:?}"
+        );
+        None
+    }
 }