🤖 feat: implement fork for local workspaces #1721
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Add fork support for LocalRuntime (project-dir mode workspaces). For LocalRuntime, fork creates a new workspace entry pointing to the same project directory with copied chat history - enabling conversation branching without git worktree overhead. Changes: - LocalRuntime.forkWorkspace() now returns success with project path - Updated LocalRuntime class docs and tests - Added integration tests for local workspace fork
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Added a stat check to verify the project directory exists before returning success from LocalRuntime.forkWorkspace(). This ensures users get a clear error rather than a broken workspace when the project directory is missing or inaccessible. Addresses review comment about defensive validation.
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## Summary Fix local workspace fork creating corrupt worktree workspaces by persisting `runtimeConfig` in `config.addWorkspace()`, then simplify the codebase by removing redundant inline fallbacks. ## Background PR #1721 (commit 4238ff4) added fork support for local (project-dir) workspaces. The `LocalRuntime.forkWorkspace()` was correctly implemented to return the project path, and `workspaceService.fork()` correctly assembled the `FrontendWorkspaceMetadata` with `runtimeConfig: forkedRuntimeConfig`. However, when `config.addWorkspace()` stored the forked workspace entry, it **discarded the runtimeConfig field**: ```typescript const workspaceEntry: Workspace = { path: workspacePath, id: metadata.id, name: metadata.name, createdAt: metadata.createdAt, // runtimeConfig was missing! }; ``` On subsequent config loads, `getAllWorkspaceMetadata()` would see no `runtimeConfig` and apply `DEFAULT_RUNTIME_CONFIG` (type: "worktree" with srcBaseDir), causing the forked workspace to be treated as a worktree runtime. This created "corrupt worktree" errors because WorktreeRuntime operations would fail on directories that were never set up as git worktrees. ## Implementation ### Commit 1: Fix runtimeConfig persistence One-line fix: include `runtimeConfig: metadata.runtimeConfig` in the workspace entry when calling `addWorkspace()`. ### Commit 2: Remove redundant fallbacks The config layer already guarantees every `WorkspaceMetadata` has a `runtimeConfig` (via `DEFAULT_RUNTIME_CONFIG` applied in `getAllWorkspaceMetadata()`). This commit removes 13 inline `?? { type: "local", srcBaseDir }` fallbacks across 5 service files that were: - **Redundant**: The metadata type already includes runtimeConfig - **Inconsistent**: Inline fallbacks used `type: "local"` while the canonical default is `type: "worktree"` - **Bug-masking**: Silently substituting values instead of surfacing issues Files cleaned up: - `workspaceService.ts` (5 locations) - `agentSession.ts` (5 locations) - `aiService.ts`, `terminalService.ts`, `workspaceMcpOverridesService.ts` (1 each) ### Commit 3: Fix namedWorkspacePath persistence (Codex review feedback) `config.addWorkspace()` was hardcoding worktree-style paths (`~/.mux/src/...`) even for local workspaces. After app restart, this caused Open-in-Editor and path display to use the wrong directory. Fix: use `namedWorkspacePath` from the metadata if provided (which is computed runtime-aware by `Runtime.getWorkspacePath()`), falling back to worktree-style path only for legacy callers. ## Validation - Integration tests for fork persistence: - Creates local workspace → forks → verifies runtimeConfig survives reload - Verifies `namedWorkspacePath` is the project path (not `~/.mux/src/...`) after reload - `make typecheck` passes - `make static-check` passes - `TEST_INTEGRATION=1 bun x jest tests/ipc/forkWorkspace.test.ts` - all 9 tests pass --- _Generated with `mux` · Model: `anthropic:claude-sonnet-4-20250514`_ <!-- mux-attribution: model=anthropic:claude-sonnet-4-20250514 -->
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Add fork support for LocalRuntime (project-dir mode workspaces).
Summary
For LocalRuntime, fork creates a new workspace entry pointing to the same project directory with copied chat history - enabling conversation branching without git worktree overhead.
Changes
LocalRuntime.forkWorkspace()now returns success with project path instead of an errortests/ipc/forkWorkspace.test.tsHow It Works
When forking a LocalRuntime workspace:
LocalRuntime.forkWorkspace()succeeds (returns project path)workspaceService.fork()copies chat history filesThis enables users to fork conversations to explore different directions without creating separate git worktrees.
Generated with
mux• Model:anthropic:claude-opus-4-5• Thinking:high• Cost:$1.55