fix(utils): address CodeRabbit review feedback on git-bash discovery

Three improvements suggested by CodeRabbit's PR review:

1. Use path.win32 for processing `where.exe` results (MAJOR). On POSIX
   hosts, `path.resolve('C:\\foo')` treats backslashes as literal
   characters and produces a wrong (relative) result, which would let
   cwd shadowing slip past the security check. Switch to `path.win32.*`
   so the cwd filtering evaluates `where.exe`'s Windows-style paths
   with Windows semantics regardless of host OS.

   Also switched the cwd check from `startsWith` to `path.win32.relative`,
   which is more robust: returns `''` for cwd itself, `..`/`../...` for
   outside, and a non-absolute path for inside. Avoids edge cases with
   trailing separators and mixed case.

2. Inject `USERPROFILE` through `GitBashDiscoveryDeps` (NITPICK). The
   Scoop fallback in `searchDefaultBashLocations` was reading
   `process.env.USERPROFILE` directly, breaking hermetic testing of
   that branch. Threaded through as an optional deps field, defaults
   to `process.env.USERPROFILE` for production.

3. Add `envOverride: ''` to the manual `GitBashDiscoveryDeps` fixture
   in the "skips where.exe git when bash is already found via PATH"
   test (INLINE). Without this, the test would pass for the wrong
   reason (env override) on developer machines that have
   `CLAUDE_CODE_GIT_BASH_PATH` set, instead of exercising the PATH
   short-circuit behavior the test is named after.

Co-Authored-By: Claude <noreply@anthropic.com>

Author: hongye

src/utils/__tests__/windowsPaths.test.ts

@@ -287,6 +287,10 @@ describe('findGitBashPathOrNullWithDeps', () => {
         return ''
       },
       cwdFn: () => '/safe/cwd',
+      // Bypass process.env.CLAUDE_CODE_GIT_BASH_PATH so the test exercises
+      // the intended PATH short-circuit behavior rather than passing for
+      // the wrong reason (env override).
+      envOverride: '',
     }
     expect(findGitBashPathOrNullWithDeps(deps)).toBe(bashPath)
     expect(gitProbed).toBe(false)

src/utils/windowsPaths.ts

@@ -35,6 +35,13 @@ export type GitBashDiscoveryDeps = {
   execCommand: (cmd: string) => string
   /** Returns the current working directory (used to filter PATH-based lookups). */
   cwdFn: () => string
+  /**
+   * `USERPROFILE` used to derive Scoop Git install paths. When provided,
+   * this is used instead of `process.env.USERPROFILE` — keeps the pure
+   * helper hermetic so the Scoop fallback can be tested without
+   * depending on the live environment.
+   */
+  userProfile?: string | undefined
   /**
    * Optional override for `process.env.CLAUDE_CODE_GIT_BASH_PATH`. When
    * provided, this is used instead of the live environment — useful for tests.
@@ -47,6 +54,7 @@ const DEFAULT_DEPS: GitBashDiscoveryDeps = {
   execCommand: cmd =>
     execSync_DEPRECATED(cmd, { stdio: 'pipe', encoding: 'utf8' }).trim(),
   cwdFn: getCwd,
+  userProfile: process.env.USERPROFILE,
   envOverride: undefined,
 }
 
@@ -57,6 +65,7 @@ const DEFAULT_DEPS: GitBashDiscoveryDeps = {
  */
 function searchDefaultBashLocations(
   checkExists: (p: string) => boolean,
+  userProfile?: string,
 ): string | null {
   const candidates = [
     // Standard Git for Windows install locations (both layouts).
@@ -66,7 +75,6 @@ function searchDefaultBashLocations(
     'C:\\Program Files (x86)\\Git\\usr\\bin\\bash.exe',
   ]
   // Scoop install: %USERPROFILE%\scoop\apps\git\current\usr\bin\bash.exe
-  const userProfile = process.env.USERPROFILE
   if (userProfile) {
     candidates.push(
       `${userProfile}\\scoop\\apps\\git\\current\\usr\\bin\\bash.exe`,
@@ -114,16 +122,35 @@ function findExecutableWithDeps(
     const result = deps.execCommand(`where.exe ${executable}`)
     // SECURITY: Filter out any results from the current directory
     // to prevent executing malicious git.bat/cmd/exe files
-    const paths = result.split('\r\n').filter(Boolean)
-    const cwd = deps.cwdFn().toLowerCase()
+    //
+    // Use path.win32.* here so that `where.exe`'s Windows-style backslash
+    // paths are evaluated with Windows semantics regardless of the host
+    // OS. On POSIX, `path.resolve('C:\\foo')` treats the backslashes as
+    // literal characters and produces a wrong (relative) result, which
+    // would let cwd shadowing slip past this check. pathWin32 is
+    // already imported for the bash derivation below.
+    const paths = result
+      .split(/\r?\n/)
+      .map(p => p.trim())
+      .filter(Boolean)
+    const cwd = pathWin32.resolve(deps.cwdFn()).toLowerCase()
 
     for (const candidatePath of paths) {
       // Normalize and compare paths to ensure we're not in current directory
-      const normalizedPath = path.resolve(candidatePath).toLowerCase()
-      const pathDir = path.dirname(normalizedPath).toLowerCase()
+      const normalizedPath = pathWin32.resolve(candidatePath).toLowerCase()
+      const pathDir = pathWin32.dirname(normalizedPath).toLowerCase()
+      // path.win32.relative(cwd, pathDir) returns:
+      //   ''               → pathDir === cwd
+      //   '..' / '../...'   → pathDir is outside cwd (or above it)
+      //   'subdir/...'     → pathDir is inside cwd
+      // We reject entries whose dir is cwd itself or anywhere inside cwd.
+      const relativePathDir = pathWin32.relative(cwd, pathDir)
 
-      // Skip if the executable is in the current working directory
-      if (pathDir === cwd || normalizedPath.startsWith(cwd + path.sep)) {
+      if (
+        relativePathDir === '' ||
+        (!relativePathDir.startsWith('..') &&
+          !pathWin32.isAbsolute(relativePathDir))
+      ) {
         logForDebugging(
           `Skipping potentially malicious executable in current directory: ${candidatePath}`,
         )
@@ -188,7 +215,7 @@ export function findGitBashPathOrNullWithDeps(
   }
 
   // 4. Last resort: scan common install locations for bash.exe directly
-  return searchDefaultBashLocations(deps.checkExists)
+  return searchDefaultBashLocations(deps.checkExists, deps.userProfile)
 }
 
 /**