Add test coverage for worktree directory switching and fix main worktree detection

- Add pragma: no branch for unreachable break in _update_worktrees_cache_after_checkout
- Add get_main_worktree_path() method to reliably get main worktree path regardless of current directory
- Use get_main_worktree_path() instead of get_root_dir() in traverse() to fix bug where main_worktree_path was incorrectly set to linked worktree when traverse started from linked worktree
- Add flush_caches() calls after os.chdir() to invalidate cached root_dir
- Add __root_dir to list of caches flushed by flush_caches()
- Add test_traverse_cd_from_linked_to_main_worktree test to cover lines 88-89 (cd from linked to main worktree) and line 477 (return to initial directory)
- Improve coverage from 98% to 99% for traverse.py

Author: PawelLipski

git_machete/client/traverse.py

@@ -63,7 +63,7 @@ def _update_worktrees_cache_after_checkout(self, checked_out_branch: LocalBranch
         for branch, path in self.__worktrees_cache.items():
             if path == current_worktree_path:
                 del self.__worktrees_cache[branch]
-                break
+                break  # pragma: no branch
 
         # Add the new branch entry for this worktree
         self.__worktrees_cache[checked_out_branch] = current_worktree_path
@@ -87,6 +87,8 @@ def _switch_to_branch_worktree(
             if current_worktree_root != main_worktree_path:
                 print(f"Changing directory to main worktree at {bold(main_worktree_path)}")
                 os.chdir(main_worktree_path)
+                # Flush cache after directory change so get_root_dir() returns the correct path
+                self._git.flush_caches()
             self._git.checkout(branch)
             # Update cache after checkout
             self._update_worktrees_cache_after_checkout(branch)
@@ -97,6 +99,8 @@ def _switch_to_branch_worktree(
                 print(f"Branch {bold(branch)} is checked out in worktree at {bold(worktree_path)}")
                 print("Changing directory to that worktree")
                 os.chdir(worktree_path)
+                # Flush cache after directory change so get_root_dir() returns the correct path
+                self._git.flush_caches()
 
     def traverse(
             self,
@@ -139,7 +143,7 @@ def traverse(
             current_user = self.code_hosting_client.get_current_user_login()
 
         # Store the main worktree path and initial directory for later restoration
-        main_worktree_path = self._git.get_root_dir()
+        main_worktree_path = self._git.get_main_worktree_path()
         initial_directory = os.getcwd()
         initial_branch = nearest_remaining_branch = self._git.get_current_branch()
 

git_machete/git_operations.py

@@ -253,6 +253,7 @@ def flush_caches(self) -> None:
         self.__remote_branches_cached = None
         self.__remotes_cached = None
         self.__removed_from_remote = None
+        self.__root_dir = None
         self.__short_commit_hash_by_revision_cached = {}
 
     def _run_git(self, git_cmd: str, *args: str, flush_caches: bool, allow_non_zero: bool = False) -> int:
@@ -622,6 +623,25 @@ def get_worktree_path(self, branch: LocalBranchShortName) -> Optional[str]:
         worktrees = self.get_worktrees()
         return worktrees.get(branch)
 
+    def get_main_worktree_path(self) -> str:
+        """
+        Returns the path to the main worktree (not a linked worktree).
+        """
+        if self.get_git_version() < (2, 5):
+            # git worktree command was introduced in git 2.5
+            # If worktrees aren't supported, just return the current root dir
+            return self.get_root_dir()
+
+        result = self._popen_git("worktree", "list", "--porcelain")
+
+        # The first worktree in the list is always the main worktree
+        for line in result.stdout.strip().splitlines():
+            if line.startswith('worktree '):
+                return line[len('worktree '):]
+
+        # Fallback: if no worktrees found, return current root dir
+        return self.get_root_dir()
+
     def checkout(self, branch: LocalBranchShortName) -> None:
         self._run_git("checkout", "--quiet", branch, "--", flush_caches=True)
 

tests/test_traverse.py

@@ -1993,3 +1993,59 @@ def test_traverse_with_worktrees(self) -> None:
         # feature-2 should now be based on the updated feature-1
         feature_2_log = subprocess.check_output("git log --oneline feature-2", shell=True).decode()
         assert "feature-1 additional commit" in feature_2_log
+
+    def test_traverse_cd_from_linked_to_main_worktree(self) -> None:
+        """Test traverse cd from linked worktree to main worktree for non-checked-out branch."""
+        if get_git_version() < (2, 5):
+            # git worktree command was introduced in git 2.5
+            return
+
+        (local_path, _) = create_repo_with_remote()
+        new_branch("root")
+        commit()
+        push()
+        new_branch("branch-1")
+        commit()
+        push()
+
+        body: str = \
+            """
+            root
+              branch-1
+            """
+        rewrite_branch_layout_file(body)
+
+        check_out("root")
+        new_branch("branch-2")
+        commit()
+        push()
+
+        body = """
+        root
+          branch-1
+          branch-2
+        """
+        rewrite_branch_layout_file(body)
+
+        # Setup: Main worktree on branch-2, linked worktree for branch-1
+        check_out("branch-2")  # Main worktree on branch-2
+        branch_1_worktree = add_worktree("branch-1")  # Linked worktree for branch-1
+
+        # cd into branch-1 linked worktree
+        os.chdir(branch_1_worktree)
+
+        # Now run traverse --start-from=first-root
+        # This should checkout root, which is NOT in any worktree
+        # We're currently in branch-1 linked worktree
+        # So it should cd to main worktree (lines 88-89)
+        output = launch_command("traverse", "-y", "--return-to=here", "--start-from=first-root")
+
+        # Verify lines 88-89 were executed
+        assert "Changing directory to main worktree at" in output, \
+            f"Expected 'Changing directory to main worktree at' in output, but got:\n{output}"
+
+        # Verify we returned to branch-1 worktree (line 475)
+        current_dir = os.path.realpath(os.getcwd())
+        branch_1_worktree_real = os.path.realpath(branch_1_worktree)
+        assert current_dir == branch_1_worktree_real, \
+            f"Expected to be in {branch_1_worktree_real}, but in {current_dir}"