singularity-forge/.gsd/milestones/M001/slices/S03/tasks/T01-PLAN.md

estimated_steps	estimated_files
5	1

T01: Fix worktree create ordering and add deterministic merge dispatch

Slice: S03 — Bug fixes and doc corrections Milestone: M001

Description

Fix two bugs in worktree-command.ts: (1) handleCreate() calls createWorktree() before autoCommitCurrentBranch(), meaning new worktrees fork from uncommitted HEAD — swap these so dirty state is committed first. (2) handleMerge() always dispatches to the LLM for merge even though mergeWorktreeToMain() exists as a deterministic helper — make the deterministic path the default, falling back to LLM only when a merge conflict occurs.

Steps

1. Add imports: Import mergeWorktreeToMain from ./worktree-manager.js and inferCommitType from ./git-service.js at the top of worktree-command.ts.
2. Fix handleCreate ordering (R007): Move the autoCommitCurrentBranch(basePath, "worktree-switch", name) call to occur BEFORE createWorktree(mainBase, name). The autoCommitCurrentBranch uses basePath (current workspace), while createWorktree uses mainBase — no dependency conflict.
3. Add deterministic merge path in handleMerge (R008): After the confirmation prompt and CWD switch (where process.chdir(basePath) already happens), insert a try/catch block that: (a) builds a conventional commit message using inferCommitType(name) and the worktree name as scope/description, (b) calls mergeWorktreeToMain(basePath, name, commitMessage), (c) on success, notifies the user and returns early (skipping LLM dispatch).
4. Add conflict fallback: In the catch block for the deterministic merge, check if the error message indicates a merge conflict (contains "conflict" or "CONFLICT"). If so, run git merge --abort to clean up, then fall through to the existing LLM dispatch path with a notification that deterministic merge failed due to conflicts. If the error is NOT a conflict, surface it to the user and return (don't fall back to LLM for non-conflict errors).
5. Verify: Run npm run build to confirm compilation. Run grep -n to confirm ordering fix and presence of deterministic merge call.

Must-Haves

• autoCommitCurrentBranch() call precedes createWorktree() call in handleCreate()
• mergeWorktreeToMain() attempted as first merge strategy in handleMerge()
• Commit message for deterministic merge uses inferCommitType(name) for the type
• Merge conflicts detected and handled: git merge --abort + LLM fallback
• Non-conflict errors surfaced to user, not silently swallowed
• npm run build passes

Verification

• npm run build completes without errors
• grep -n 'autoCommitCurrentBranch\|createWorktree' src/resources/extensions/gsd/worktree-command.ts — autoCommit line number < createWorktree line number in handleCreate
• grep -n 'mergeWorktreeToMain' src/resources/extensions/gsd/worktree-command.ts — appears in handleMerge function
• npm run test — existing tests still pass (4 pre-existing failures acceptable)

Observability Impact

• Signals added/changed: ctx.ui.notify messages for deterministic merge success, conflict fallback, and non-conflict errors
• How a future agent inspects this: Read the notification messages in the TUI after a merge operation
• Failure state exposed: Conflict detection triggers a visible notification before LLM fallback; non-conflict errors show the error message directly

Inputs

• src/resources/extensions/gsd/worktree-command.ts — current handleCreate (lines 348-390) and handleMerge (lines 572-710) implementations
• src/resources/extensions/gsd/worktree-manager.ts — mergeWorktreeToMain(basePath, name, commitMessage) at line 379
• src/resources/extensions/gsd/git-service.ts — inferCommitType(sliceTitle) at line 354
• S03-RESEARCH.md — confirmed bug locations and existing function signatures

Expected Output

• src/resources/extensions/gsd/worktree-command.ts — handleCreate has autoCommit before createWorktree; handleMerge attempts deterministic mergeWorktreeToMain before LLM dispatch with proper conflict handling