fix(worktree): find parent repo for bare clones

Running git-branchless from a linked worktree of a bare-clone repo
caused a fatal crash rather than displaying output.

Author: feosuna1

git-branchless-lib/src/git/repo.rs

@@ -577,20 +577,7 @@ impl Repo {
             return Ok(None);
         }
 
-        // `git2` doesn't seem to support a way to directly look up the parent repository for the
-        // worktree.
-        let worktree_info_dir = self.get_path();
-        let parent_repo_path = match worktree_info_dir
-            .parent() // remove `.git`
-            .and_then(|path| path.parent()) // remove worktree name
-            .and_then(|path| path.parent()) // remove `worktrees`
-        {
-            Some(path) => path,
-            None => {
-                return Err(Error::OpenParentWorktreeRepository {
-                    path: worktree_info_dir.to_owned()});
-            },
-        };
+        let parent_repo_path = self.inner.commondir();
         let parent_repo = Self::from_dir(parent_repo_path)?;
         Ok(Some(parent_repo))
     }

git-branchless-lib/tests/test_repo.rs

@@ -4,7 +4,7 @@ use branchless::git::{
     AmendFastOptions, BranchType, CherryPickFastOptions, FileMode, FileStatus, GitVersion, Repo,
     StatusEntry,
 };
-use branchless::testing::{GitWorktreeWrapper, make_git, make_git_worktree};
+use branchless::testing::{Git, GitWorktreeWrapper, make_git, make_git_worktree};
 
 #[test]
 fn test_parse_git_version_output() {
@@ -303,3 +303,42 @@ fn test_worktree_working_copy_path() -> eyre::Result<()> {
 
     Ok(())
 }
+
+#[test]
+fn test_open_worktree_parent_repo_bare_clone() -> eyre::Result<()> {
+    let git = make_git()?;
+    git.init_repo()?;
+    git.commit_file("test1", 1)?;
+
+    let temp_dir = tempfile::tempdir()?;
+    let bare_path = temp_dir.path().join("bare");
+    let worktree_path = temp_dir.path().join("worktree");
+
+    // Create a bare clone.
+    let source = format!("file://{}", git.repo_path.to_str().unwrap());
+    git.run(&["clone", "--bare", &source, bare_path.to_str().unwrap()])?;
+
+    // Create a linked worktree from the bare clone.
+    let bare_git = Git {
+        repo_path: bare_path.clone(),
+        ..(*git).clone()
+    };
+    bare_git.run(&[
+        "worktree",
+        "add",
+        "--detach",
+        worktree_path.to_str().unwrap(),
+    ])?;
+
+    let worktree_repo = Repo::from_dir(&worktree_path)?;
+    let parent_repo = worktree_repo
+        .open_worktree_parent_repo()?
+        .expect("expected to find parent repo for worktree of bare clone");
+    assert_eq!(
+        std::fs::canonicalize(parent_repo.get_path())?,
+        std::fs::canonicalize(&bare_path)?,
+    );
+
+    drop(temp_dir);
+    Ok(())
+}