fix: more robust computation of git directory

Author: cramakri

src/scms/git.js

@@ -14,18 +14,30 @@ export const detect = (directory) => {
     cwd: directory,
     type: 'directory',
   });
-  if (gitDirectory) {
-    return dirname(gitDirectory);
-  }
 
   const gitWorktreeFile = findUp.sync('.git', {
     cwd: directory,
     type: 'file',
   });
+  // if both of these are null then return null
+  if (!gitDirectory && !gitWorktreeFile) {
+    return null;
+  }
 
-  if (gitWorktreeFile) {
+  // if only one of these exists then return it
+  if (gitDirectory && !gitWorktreeFile) {
+    return dirname(gitDirectory);
+  }
+  if (gitWorktreeFile && !gitDirectory) {
     return dirname(gitWorktreeFile);
   }
+
+  const gitRepoDirectory = dirname(gitDirectory);
+  const gitWorktreeDirectory = dirname(gitWorktreeFile);
+  // return the deeper of these two
+  return gitRepoDirectory.length > gitWorktreeDirectory.length
+    ? gitRepoDirectory
+    : gitWorktreeDirectory;
 };
 
 const runGit = (directory, args) =>