Fix git root detection in worktrees (#389)

* Fix git root detection in worktrees

* Change files

* update naming

change/backfill-2021-09-20-22-47-29-worktrees.json

@@ -0,0 +1,8 @@
+{
+  "type": "patch",
+  "comment": "Fix git root detection in worktrees",
+  "packageName": "backfill",
+  "email": "[email protected]",
+  "dependentChangeType": "patch",
+  "date": "2021-09-21T05:47:28.208Z"
+}

change/backfill-cache-2021-09-20-22-47-29-worktrees.json

@@ -0,0 +1,8 @@
+{
+  "type": "patch",
+  "comment": "Fix git root detection in worktrees",
+  "packageName": "backfill-cache",
+  "email": "[email protected]",
+  "dependentChangeType": "patch",
+  "date": "2021-09-21T05:47:29.059Z"
+}

packages/backfill/src/audit.ts

@@ -11,14 +11,14 @@ let changedFilesInsideScope: string[] = [];
 let watcher: chokidar.FSWatcher;
 
 function getGitRepositoryRoot(packageRoot: string) {
-  const nearestGitFolder = findUp.sync(".git", {
-    cwd: packageRoot,
-    type: "directory",
-  });
+  // .git is typically a folder but will be a file in a worktree
+  const nearestGitInfo =
+    findUp.sync(".git", { cwd: packageRoot, type: "directory" }) ||
+    findUp.sync(".git", { cwd: packageRoot, type: "file" });
 
-  if (nearestGitFolder) {
+  if (nearestGitInfo) {
     // Return the parent folder of some/path/.git
-    return path.join(nearestGitFolder, "..");
+    return path.join(nearestGitInfo, "..");
   }
 
   return packageRoot;

packages/cache/src/CacheStorage.ts

@@ -8,14 +8,17 @@ import { Logger } from "backfill-logger";
 const savedHashOfRepos: { [gitRoot: string]: { [file: string]: string } } = {};
 
 function getRepoRoot(cwd: string): string {
-  const gitFolder = findUp.sync(".git", { cwd, type: "directory" });
-  if (!gitFolder) {
+  // .git is typically a folder but will be a file in a worktree
+  const nearestGitInfo =
+    findUp.sync(".git", { cwd, type: "directory" }) ||
+    findUp.sync(".git", { cwd, type: "file" });
+  if (!nearestGitInfo) {
     throw new Error(
       "The location that backfill is being run against is not in a git repo"
     );
   }
 
-  return dirname(gitFolder);
+  return dirname(nearestGitInfo);
 }
 
 function fetchHashesFor(cwd: string) {