fix: detect git repo root correctly on cygwin (#1026)

* Fix  #1025 using git rev-parse to get the relative path inside git repo

Co-authored-by: Thomas Kalmar <[email protected]>

lib/resolveGitRepo.js

@@ -25,10 +25,20 @@ const resolveGitConfigDir = async (gitDir) => {
   return path.resolve(gitDir, file.replace(/^gitdir: /, '')).trim()
 }
 
+const determineGitDir = (cwd, relativeDir) => {
+  if (relativeDir) {
+    // the current working dir is inside the git top-level directory
+    return normalize(cwd.substring(0, cwd.lastIndexOf(relativeDir)))
+  } else {
+    // the current working dir is the top-level git directory
+    return normalize(cwd)
+  }
+}
+
 /**
  * Resolve git directory and possible submodule paths
  */
-const resolveGitRepo = async (cwd) => {
+const resolveGitRepo = async (cwd = process.cwd()) => {
   try {
     debugLog('Resolving git repo from `%s`', cwd)
 
@@ -38,7 +48,10 @@ const resolveGitRepo = async (cwd) => {
     debugLog('Unset GIT_WORK_TREE (was `%s`)', process.env.GIT_WORK_TREE)
     delete process.env.GIT_WORK_TREE
 
-    const gitDir = normalize(await execGit(['rev-parse', '--show-toplevel'], { cwd }))
+    // read the path of the current directory relative to the top-level directory
+    // don't read the toplevel directly, it will lead to an posix conform path on non posix systems (cygwin)
+    const gitRel = normalize(await execGit(['rev-parse', '--show-prefix']))
+    const gitDir = determineGitDir(cwd, gitRel)
     const gitConfigDir = normalize(await resolveGitConfigDir(gitDir))
 
     debugLog('Resolved git directory to be `%s`', gitDir)