chore: remove dead code from branchless refactor (#510)

Remove methods, fields, and comments left over after the branchless
worktree architecture landed:

- git-service.ts: delete isOnSliceBranch, getActiveSliceBranch,
  branchExists (private), discardUntrackedRuntimeFiles (private);
  update writeIntegrationBranch comment and remove --force flag
- worktree.ts: delete isOnSliceBranch, getActiveSliceBranch exports;
  update module doc from "branch-per-slice" to "worktree utilities"
- state.ts: remove activeBranch computation (always null)
- types.ts: remove GSDState.activeBranch field
- templates/state.md: remove "Slice Branch" line
- auto.ts, guided-flow.ts: update "branch-per-slice" comments
- Tests updated to match

Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/resources/extensions/gsd/auto.ts

@@ -553,7 +553,7 @@ export async function startAuto(
     return;
   }
 
-  // Ensure git repo exists — GSD needs it for branch-per-slice
+  // Ensure git repo exists — GSD needs it for worktree isolation
   try {
     execSync("git rev-parse --git-dir", { cwd: base, stdio: "pipe" });
   } catch {

src/resources/extensions/gsd/git-service.ts

@@ -132,13 +132,11 @@ export function readIntegrationBranch(basePath: string, milestoneId: string): st
  * Persist the integration branch for a milestone.
  *
  * Called when auto-mode starts on a milestone. Records the branch the user
- * was on at that point, so that slice branches merge back to it instead of
- * the repo's default branch. Idempotent when the branch matches; updates
- * the record when the user starts from a different branch.
+ * was on at that point, so the milestone worktree merges back to the correct
+ * branch. Idempotent when the branch matches; updates the record when the
+ * user starts from a different branch.
  *
- * The file is committed immediately so it survives branch switches — the
- * pre-switch auto-commit excludes `.gsd/` to avoid merge conflicts, and
- * uncommitted `.gsd/` files are discarded during checkout.
+ * The file is committed immediately so the metadata is persisted in git.
  */
 export function writeIntegrationBranch(basePath: string, milestoneId: string, branch: string): void {
   // Don't record slice branches as the integration target
@@ -167,7 +165,7 @@ export function writeIntegrationBranch(basePath: string, milestoneId: string, br
 
   // Commit immediately so the metadata is persisted in git.
   try {
-    runGit(basePath, ["add", "--force", metaFile]);
+    runGit(basePath, ["add", metaFile]);
     runGit(basePath, ["commit", "--no-verify", "-F", "-"], {
       input: `chore(${milestoneId}): record integration branch`,
     });
@@ -404,48 +402,8 @@ export class GitServiceImpl {
   }
 
   /** True if currently on a GSD slice branch. */
-  isOnSliceBranch(): boolean {
-    const current = this.getCurrentBranch();
-    return SLICE_BRANCH_RE.test(current);
-  }
-
-  /** Returns the slice branch name if on one, null otherwise. */
-  getActiveSliceBranch(): string | null {
-    try {
-      const current = this.getCurrentBranch();
-      return SLICE_BRANCH_RE.test(current) ? current : null;
-    } catch {
-      return null;
-    }
-  }
-
   // ─── Branch Lifecycle ──────────────────────────────────────────────────
 
-  /**
-   * Check if a local branch exists. Native libgit2 when available, execSync fallback.
-   */
-  private branchExists(branch: string): boolean {
-    return nativeBranchExists(this.basePath, branch);
-  }
-
-  /**
-   * Remove untracked runtime files from the working tree.
-   *
-   * Complements `git checkout -- .gsd/` (which only handles tracked files).
-   * Runtime files can end up untracked after a cleanup commit removes them
-   * from the current branch's HEAD — but the target branch may still have
-   * them committed. Without this step, `git checkout` fails with:
-   *   "The following untracked working tree files would be overwritten by checkout"
-   *
-   * `git clean -fdx` is safe here because:
-   * - Only removes *untracked* files (tracked files are untouched)
-   * - Targets only the specific runtime paths listed in RUNTIME_EXCLUSION_PATHS
-   * - These files are always regenerated by GSD on the next run
-   */
-  private discardUntrackedRuntimeFiles(): void {
-    this.git(["clean", "-fdx", "--", ...RUNTIME_EXCLUSION_PATHS], { allowFailure: true });
-  }
-
   // ─── S05 Features ─────────────────────────────────────────────────────
 
   /**

src/resources/extensions/gsd/guided-flow.ts

@@ -700,7 +700,7 @@ export async function showSmartEntry(
 ): Promise<void> {
   const stepMode = options?.step;
 
-  // ── Ensure git repo exists — GSD needs it for branch-per-slice ──────
+  // ── Ensure git repo exists — GSD needs it for worktree isolation ──────
   try {
     execSync("git rev-parse --git-dir", { cwd: basePath, stdio: "pipe" });
   } catch {

src/resources/extensions/gsd/state.ts

@@ -29,7 +29,7 @@ import {
   resolveGsdRootFile,
   gsdRoot,
 } from './paths.js';
-import { getActiveSliceBranch } from './worktree.js';
+
 import { milestoneIdSort, findMilestoneIds } from './guided-flow.js';
 import { nativeBatchParseGsdFiles, type BatchParsedFile } from './native-parser-bridge.js';
 
@@ -438,8 +438,6 @@ async function _deriveStateImpl(basePath: string): Promise<GSDState> {
     };
   }
 
-  const activeBranch = getActiveSliceBranch(basePath);
-
   // Check if the slice has a plan
   const planFile = resolveSliceFile(basePath, activeMilestone.id, activeSlice.id, "PLAN");
   const slicePlanContent = planFile ? await cachedLoadFile(planFile) : null;
@@ -453,7 +451,7 @@ async function _deriveStateImpl(basePath: string): Promise<GSDState> {
       recentDecisions: [],
       blockers: [],
       nextAction: `Plan slice ${activeSlice.id} (${activeSlice.title}).`,
-      activeBranch: activeBranch ?? undefined,
+
       registry,
       requirements,
       progress: {
@@ -480,7 +478,7 @@ async function _deriveStateImpl(basePath: string): Promise<GSDState> {
       recentDecisions: [],
       blockers: [],
       nextAction: `All tasks done in ${activeSlice.id}. Write slice summary and complete slice.`,
-      activeBranch: activeBranch ?? undefined,
+
       registry,
       requirements,
       progress: {
@@ -501,7 +499,7 @@ async function _deriveStateImpl(basePath: string): Promise<GSDState> {
       recentDecisions: [],
       blockers: [],
       nextAction: `Slice ${activeSlice.id} has a plan file but no tasks. Add tasks to the plan.`,
-      activeBranch: activeBranch ?? undefined,
+
       registry,
       requirements,
       progress: {
@@ -547,7 +545,7 @@ async function _deriveStateImpl(basePath: string): Promise<GSDState> {
         recentDecisions: [],
         blockers: [`Task ${blockerTaskId} discovered a blocker requiring slice replan`],
         nextAction: `Task ${blockerTaskId} reported blocker_discovered. Replan slice ${activeSlice.id} before continuing.`,
-        activeBranch: activeBranch ?? undefined,
+  
         activeWorkspace: undefined,
         registry,
         requirements,
@@ -578,7 +576,6 @@ async function _deriveStateImpl(basePath: string): Promise<GSDState> {
     nextAction: hasInterrupted
       ? `Resume interrupted work on ${activeTask.id}: ${activeTask.title} in slice ${activeSlice.id}. Read continue.md first.`
       : `Execute ${activeTask.id}: ${activeTask.title} in slice ${activeSlice.id}.`,
-    activeBranch: activeBranch ?? undefined,
     registry,
     requirements,
     progress: {

src/resources/extensions/gsd/templates/state.md

@@ -4,7 +4,6 @@
 **Active Slice:** {{sliceId}}: {{sliceTitle}}
 **Active Task:** {{taskId}}: {{taskTitle}}
 **Phase:** {{phase}}
-**Slice Branch:** {{activeBranch}}
 **Active Workspace:** {{activeWorkspace}}
 **Next Action:** {{nextAction}}
 **Last Updated:** {{date}}

src/resources/extensions/gsd/tests/git-service.test.ts

@@ -533,7 +533,7 @@ async function main(): Promise<void> {
     return dir;
   }
 
-  // ─── getCurrentBranch / isOnSliceBranch / getActiveSliceBranch ─────────
+  // ─── getCurrentBranch ────────────────────────────────────────────────
 
   console.log("\n=== Branch queries ===");
 
@@ -541,21 +541,13 @@ async function main(): Promise<void> {
     const repo = initBranchTestRepo();
     const svc = new GitServiceImpl(repo);
 
-    // On main
     assertEq(svc.getCurrentBranch(), "main", "getCurrentBranch returns main on main branch");
-    assertEq(svc.isOnSliceBranch(), false, "isOnSliceBranch returns false on main");
-    assertEq(svc.getActiveSliceBranch(), null, "getActiveSliceBranch returns null on main");
 
-    // Create and checkout a slice branch manually
     run("git checkout -b gsd/M001/S01", repo);
     assertEq(svc.getCurrentBranch(), "gsd/M001/S01", "getCurrentBranch returns slice branch name");
-    assertEq(svc.isOnSliceBranch(), true, "isOnSliceBranch returns true on slice branch");
-    assertEq(svc.getActiveSliceBranch(), "gsd/M001/S01", "getActiveSliceBranch returns branch name on slice branch");
 
-    // Non-slice feature branch
     run("git checkout -b feature/foo", repo);
-    assertEq(svc.isOnSliceBranch(), false, "isOnSliceBranch returns false on non-slice branch");
-    assertEq(svc.getActiveSliceBranch(), null, "getActiveSliceBranch returns null on non-slice branch");
+    assertEq(svc.getCurrentBranch(), "feature/foo", "getCurrentBranch returns feature branch name");
 
     rmSync(repo, { recursive: true, force: true });
   }

src/resources/extensions/gsd/tests/worktree-integration.test.ts

@@ -24,9 +24,8 @@ import {
   getCurrentBranch,
   getMainBranch,
   getSliceBranchName,
-  isOnSliceBranch,
-  getActiveSliceBranch,
   autoCommitCurrentBranch,
+  SLICE_BRANCH_RE,
 } from "../worktree.ts";
 
 import { deriveState } from "../state.ts";
@@ -109,8 +108,7 @@ async function main(): Promise<void> {
   const sliceBranch = getSliceBranchName("M001", "S01", "alpha");
   run(`git checkout -b ${sliceBranch}`, wt.path);
   assertEq(getCurrentBranch(wt.path), "gsd/alpha/M001/S01", "worktree-namespaced slice branch");
-  assertTrue(isOnSliceBranch(wt.path), "isOnSliceBranch returns true");
-  assertEq(getActiveSliceBranch(wt.path), "gsd/alpha/M001/S01", "getActiveSliceBranch returns namespaced branch");
+  assertTrue(SLICE_BRANCH_RE.test(getCurrentBranch(wt.path)), "slice branch regex matches namespaced branch");
 
   // ── Do work on slice branch, then merge to worktree branch ─────────────────
 

src/resources/extensions/gsd/tests/worktree.test.ts

@@ -7,11 +7,9 @@ import {
   autoCommitCurrentBranch,
   captureIntegrationBranch,
   detectWorktreeName,
-  getActiveSliceBranch,
   getCurrentBranch,
   getMainBranch,
   getSliceBranchName,
-  isOnSliceBranch,
   parseSliceBranch,
   setActiveMilestoneId,
   SLICE_BRANCH_RE,
@@ -37,12 +35,6 @@ run('git commit -m "chore: init"', base);
 
 async function main(): Promise<void> {
 
-  console.log("\n=== getActiveSliceBranch on main ===");
-  assertEq(getActiveSliceBranch(base), null, "getActiveSliceBranch returns null on main");
-
-  console.log("\n=== isOnSliceBranch on main ===");
-  assertEq(isOnSliceBranch(base), false, "isOnSliceBranch returns false on main");
-
   console.log("\n=== autoCommitCurrentBranch ===");
   // Clean — should return null
   const cleanResult = autoCommitCurrentBranch(base, "execute-task", "M001/S01/T01");

src/resources/extensions/gsd/types.ts

@@ -175,7 +175,6 @@ export interface GSDState {
   recentDecisions: string[];
   blockers: string[];
   nextAction: string;
-  activeBranch?: string;
   activeWorkspace?: string;
   registry: MilestoneRegistryEntry[];
   requirements?: RequirementCounts;

src/resources/extensions/gsd/worktree.ts

@@ -1,13 +1,11 @@
 /**
- * GSD Slice Branch Management — Thin Facade
+ * GSD Worktree Utilities
  *
- * Simple branch-per-slice workflow. No worktrees, no registry.
- * Runtime state (metrics, activity, lock, STATE.md) is gitignored
- * so branch switches are clean.
+ * Pure utility functions for worktree name detection, legacy branch name
+ * parsing, and integration branch capture.
  *
- * All git-mutation functions delegate to GitServiceImpl from git-service.ts.
  * Pure utility functions (detectWorktreeName, getSliceBranchName, parseSliceBranch,
- * SLICE_BRANCH_RE) remain standalone.
+ * SLICE_BRANCH_RE) remain standalone for backwards compatibility.
  *
  * Branchless architecture: all work commits sequentially on the milestone branch.
  * Pure utility functions (detectWorktreeName, getSliceBranchName, parseSliceBranch,
@@ -147,26 +145,4 @@ export function autoCommitCurrentBranch(
   return getService(basePath).autoCommit(unitType, unitId);
 }
 
-// ─── Query Functions (delegate to GitServiceImpl) ──────────────────────────
 
-/**
- * Check if we're currently on a slice branch (not main).
- * Handles both plain (gsd/M001/S01) and worktree-namespaced (gsd/wt/M001/S01) branches.
- */
-export function isOnSliceBranch(basePath: string): boolean {
-  const current = getCurrentBranch(basePath);
-  return SLICE_BRANCH_RE.test(current);
-}
-
-/**
- * Get the active slice branch name, or null if on main.
- * Handles both plain and worktree-namespaced branch patterns.
- */
-export function getActiveSliceBranch(basePath: string): string | null {
-  try {
-    const current = getCurrentBranch(basePath);
-    return SLICE_BRANCH_RE.test(current) ? current : null;
-  } catch {
-    return null;
-  }
-}