Replace git worktree with git clone for session isolation by kirich1409 · Pull Request #157 · androidbroadcast/Relay

kirich1409 · 2026-04-15T13:51:50Z

Summary

Replace add_worktree() / remove_worktree() with clone_for_session() / remove_session_clone() in ProjectManager
Each cloud session now gets a full git clone from the project's local repo instead of a worktree — independent .git directory, no shared lock files
Session clone cleanup is simple rm -rf instead of git worktree remove

Closes #140

Test plan

cargo fmt --check clean
cargo clippy --all-targets --all-features -- -D warnings clean
cargo test — 189 tests pass
Smoke test: create 2 sessions on different branches, work in parallel

🤖 Generated with Claude Code

Worktrees share the parent .git directory, causing lock file conflicts between concurrent sessions. Full clones give each session an independent .git — no shared state, simpler lifecycle management. - ProjectManager: add_worktree() -> clone_for_session() (local clone) - ProjectManager: remove_worktree() -> remove_session_clone() (rm -rf) - CloudSessionManager: sessions/<uuid> instead of worktrees/<uuid> Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Copilot

Pull request overview

This PR updates the runner’s cloud session isolation strategy by switching from git worktree to creating a full local git clone per session, aiming to eliminate shared .git state/lock contention between sessions.

Changes:

Replace per-session git worktree add/remove with git clone + directory deletion APIs in ProjectManager.
Update cloud session creation to create a per-session clone directory and pass it into the container environment.
Refresh docs/comments to reflect the new isolation approach.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 4 comments.

File	Description
runner/src/project_manager.rs	Replaces worktree management with `clone_for_session()` and `remove_session_clone()` helpers.
runner/src/cloud_session_manager.rs	Creates a per-session clone directory instead of a worktree and uses it as the workspace path for the session container.
runner/src/main.rs	Updates init comment about the data-dir subdirectories (workspaces vs session clones).

Comments suppressed due to low confidence (1)

runner/src/cloud_session_manager.rs:176

The session clone path isn’t persisted anywhere (CreateSession.work_dir is left empty), which makes later cleanup/recovery impossible and leaves ProjectManager::remove_session_clone effectively unused. Consider storing clone_dir into work_dir (and using that field for cleanup on stop/delete/reconcile) so clones don’t accumulate on disk.

        // 4. Create session record in DB (state = Starting).
        let effective_image = image
            .unwrap_or_else(|| self.docker.default_image())
            .to_owned();
        let profile_name = profile.unwrap_or("default").to_owned();
        let db_session = self
            .store
            .create_session(store::CreateSession {
                project_id: project_id.to_owned(),
                branch: branch.to_owned(),
                image: effective_image.clone(),
                profile: profile_name.clone(),
                work_dir: String::new(),
            })

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Copilot · 2026-04-15T13:58:07Z


    let data_dir = config::Config::default().data_dir;
-    // "workspaces" dir holds git worktrees for session isolation (legacy name, not a domain entity)
+    // "workspaces" dir holds session clones for isolation (legacy name, not a domain entity)


This comment says the top-level <data_dir>/workspaces directory “holds session clones”, but session clones are created under <data_dir>/projects/<project_id>/sessions/<uuid> in CloudSessionManager. Please update the comment (or align the clone location) so the initialization docs match runtime behavior.

Suggested change

// "workspaces" dir holds session clones for isolation (legacy name, not a domain entity)

// Session clones are stored under per-project paths in "projects/.../sessions/...".

// Keep the top-level "workspaces" directory for legacy compatibility and other workspace data.

Copilot · 2026-04-15T13:58:08Z

+        // 3. Create isolated git clone for the branch.
        let project_dir = self.project_manager.projects_dir().join(project_id);
        // Use a unique subdirectory per session to avoid collisions.
-        let session_worktree_id = uuid::Uuid::new_v4().to_string();
-        let worktree_dir = project_dir.join(format!("worktrees/{session_worktree_id}"));
+        let session_clone_id = uuid::Uuid::new_v4().to_string();
+        let clone_dir = project_dir.join(format!("sessions/{session_clone_id}"));

        self.project_manager
-            .add_worktree(&project_dir, branch, &worktree_dir)
+            .clone_for_session(&project_dir, branch, &clone_dir)
            .await?;


clone_dir is created as <project_dir>/sessions/<uuid>, but git clone won’t create missing intermediate directories. If <project_dir>/sessions doesn’t exist, session creation will fail with “could not create leading directories”. Consider create_dir_all(clone_dir.parent().unwrap()) (or choose a base directory that is guaranteed to exist) before calling clone_for_session.

Copilot · 2026-04-15T13:58:08Z

        let output = Command::new("git")
            .args([
-                "-C",
-                &project_dir.to_string_lossy(),
-                "worktree",
-                "add",
-                &worktree_dir.to_string_lossy(),
+                "clone",
+                "--branch",
                branch,
+                &project_dir.to_string_lossy(),
+                &clone_dir.to_string_lossy(),
            ])


clone_for_session invokes git clone into clone_dir, but it doesn’t ensure the parent directory exists. Since callers may pass a nested path (e.g. .../sessions/<id>), consider creating clone_dir.parent() with tokio::fs::create_dir_all first and returning a clear error if that fails.

Copilot · 2026-04-15T13:58:08Z

+        tokio::fs::remove_dir_all(clone_dir)
            .await
            .map_err(|e| RelayError::Git {
-                message: format!("failed to spawn git worktree remove: {e}"),
-                stderr: String::new(),
-            })?;
-
-        if !output.status.success() {
-            let stderr = String::from_utf8_lossy(&output.stderr).into_owned();
-            return Err(RelayError::Git {
                message: format!(
-                    "git worktree remove failed (exit {:?})",
-                    output.status.code()
+                    "failed to remove session clone at {}: {e}",
+                    clone_dir.display()
                ),
-                stderr,
-            });
-        }
+                stderr: String::new(),
+            })?;


remove_session_clone wraps filesystem deletion failures in RelayError::Git. Since RelayError::Git maps to HTTP 400, a host filesystem issue (permissions, IO errors) would be reported as a client error. Consider introducing a dedicated filesystem/IO error variant (or mapping this case to an internal error) so operational failures surface correctly.

Merge with main pulled in two commits that invert earlier text: - #156 (f44bbd2): first session now auto-created after clone succeeds; DELETE of last session returns 400 - #157 (1d883a7): session isolation switched from git worktree back to independent git clone per session (sessions/<uuid>) Updates: - D4: restate as 1 project = 1 clone; 1 session = 1 independent clone (+ container). Alternative becomes worktree (rejected due to shared .git lock conflicts) - Session.work_dir comment: session clone directory, not worktree - Invariant: restore "Project without sessions is invalid"; document auto-create flow, retry path, and DELETE-last-session rejection - Isolation: clone-per-session with own .git, RELAY_WORKSPACE_DIR exposes it to the container Addresses copilot round 2 on PR #131.

* Align §7 Data Model and D4 with implementation reality - Add Terminal entity (1:N from Session), added in Wave 3b - Add default_image to Project, work_dir to Session - Remove stale fields (claude_session_id, current_exec_id) - Update SessionProfile fields to match code - Document invariant: project without sessions is invalid - Document session isolation: clone (cloud) vs worktree (local) - Update D4: cloud = 1 session = 1 clone = 1 container Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com> * Align §7 and D4 with runner store fields and worktree isolation - Project: add local_path, clone_error, deleted_at; drop generic error - Session: rename error → error_reason; add deleted_at - Invariant: relax "project must have a session" — Cloud clones in background without auto-creating a session, so an empty Project is a valid transitional state - Isolation: Cloud uses one git clone per project and one git worktree (plus one container) per session — not a full clone per session - D4: restate as "1 project = 1 clone; 1 session = 1 worktree + 1 container" and adjust alternatives accordingly Addresses copilot review comments on PR #131. * Re-align §7 and D4 with post-#156/#157 main state Merge with main pulled in two commits that invert earlier text: - #156 (f44bbd2): first session now auto-created after clone succeeds; DELETE of last session returns 400 - #157 (1d883a7): session isolation switched from git worktree back to independent git clone per session (sessions/<uuid>) Updates: - D4: restate as 1 project = 1 clone; 1 session = 1 independent clone (+ container). Alternative becomes worktree (rejected due to shared .git lock conflicts) - Session.work_dir comment: session clone directory, not worktree - Invariant: restore "Project without sessions is invalid"; document auto-create flow, retry path, and DELETE-last-session rejection - Isolation: clone-per-session with own .git, RELAY_WORKSPACE_DIR exposes it to the container Addresses copilot round 2 on PR #131. --------- Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Copilot AI review requested due to automatic review settings April 15, 2026 13:51

Copilot started reviewing on behalf of kirich1409 April 15, 2026 13:52 View session

kirich1409 merged commit 1d883a7 into main Apr 15, 2026
14 checks passed

kirich1409 deleted the feature/git-clone-session-isolation branch April 15, 2026 13:57

Copilot AI reviewed Apr 15, 2026

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Replace git worktree with git clone for session isolation#157

Replace git worktree with git clone for session isolation#157
kirich1409 merged 1 commit intomainfrom
feature/git-clone-session-isolation

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	// "workspaces" dir holds session clones for isolation (legacy name, not a domain entity)
	// Session clones are stored under per-project paths in "projects/.../sessions/...".
	// Keep the top-level "workspaces" directory for legacy compatibility and other workspace data.

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kirich1409 commented Apr 15, 2026

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