v1.94.3.0 fix(ship-preflight): stop when origin's default branch can't be read (#3718 follow-up) (#3913)

* fix(ship-preflight): stop when ls-remote origin HEAD fails instead of guessing the default branch

Co-authored-by: capy-ai[bot] <230910855+capy-ai[bot]@users.noreply.github.com>

* fix(ship-preflight): a remote HEAD with no branch falls back to the default-base order; docs name the whole order

Co-authored-by: capy-ai[bot] <230910855+capy-ai[bot]@users.noreply.github.com>

* changelog: say when the default-base order still reads the local origin/HEAD

Co-authored-by: capy-ai[bot] <230910855+capy-ai[bot]@users.noreply.github.com>

---------

Co-authored-by: capy-ai[bot] <230910855+capy-ai[bot]@users.noreply.github.com>

CHANGELOG.md

@@ -1,5 +1,15 @@
 # Changelog
 
+## [1.94.3.0] - 2026-11-03
+
+**`gstack-ship-preflight` no longer trusts a local `origin/HEAD` when origin can't say its default branch.** Preflight fell back to the local `origin/HEAD` whenever `git ls-remote --symref origin HEAD` failed or named no branch. With no local `origin/HEAD`, it went on from the default branch itself and merged the given base into it. When a PR-branch clone's `origin/HEAD` named the feature branch, it refused that branch as "on the base branch". Now a failed `ls-remote` stops with `git ls-remote origin HEAD failed: …; restore access first` before anything merges. A remote HEAD that names no branch (a detached HEAD, or a server that sends no symref) falls back to the shared default-base order in `lib/default-base.ts`, which uses the local `origin/HEAD` only when it doesn't name the checked-out branch, its upstream or HEAD's commit. The default-branch check now runs after the fetch, so a failed fetch still reports the fetch.
+
+### Fixed
+- **`docs/eval-calls.md`, `docs/eval-models.md`**: the default `--base` now matches base resolution: origin/HEAD's branch unless it names the checked-out branch, its upstream or HEAD's commit, then the PR's base, the remote's live HEAD, `main` or `master`.
+
+### Tests
+- `test/ship-preflight.test.ts`: with `ls-remote` failing and the fetch working, preflight stops before merging in two cases. One is the default branch with no local `origin/HEAD`, where main exited 0 and merged `release` into `main`. The other is a feature branch that the local `origin/HEAD` names, where main stopped as "on the base branch". When `ls-remote` prints only a sha, the default branch still stops as the base branch (main exited 0) and the feature branch goes on.
+
 ## [1.94.2.0] - 2026-11-03
 
 ### Fixed

VERSION

@@ -1 +1 @@
-1.94.2.0
+1.94.3.0

agents-digest/gstack-AGENTS.md

@@ -1,4 +1,4 @@
-# gstack digest v1.94.2.0 — regenerate/re-copy after upgrading gstack
+# gstack digest v1.94.3.0 — regenerate/re-copy after upgrading gstack
 
 Behavioral rules from gstack (https://github.com/garrytan/gstack), compressed
 for agent hosts without a full skill install. The full skills add workflows,

docs/eval-calls.md

@@ -22,7 +22,9 @@ dropped), so a command with quotes or `$` never passes through a shell string;
 
 1. `--plan-file <file>`: an operator-given file, read from disk.
 2. Otherwise `price_file` in `.gstack/pregate.json` as committed on
-   `origin/<base>` (`--base`, default origin/HEAD's branch): a repo-relative
+   `origin/<base>` (`--base`, default origin/HEAD's branch unless it names the
+   checked-out branch, its upstream or HEAD's commit, then the PR's base, the
+   remote's live HEAD, `main` or `master`): a repo-relative
    path whose bytes are read from the **HEAD commit** (`git show HEAD:<path>`),
    never from the working tree.
 

docs/eval-models.md

@@ -66,7 +66,9 @@ unless the command says it is a smoke run.
 ## Which copy is read
 
 By default the reviewed copy is read: `git show origin/<base>:.gstack/eval-models.json`
-(`--base`, default origin/HEAD's branch). A branch cannot loosen the rules it
+(`--base`, default origin/HEAD's branch unless it names the checked-out branch,
+its upstream or HEAD's commit, then the PR's base, the remote's live HEAD, `main`
+or `master`). A branch cannot loosen the rules it
 is checked against. When the working-tree copy differs, an
 `EVAL_MODELS_NOTE:` line says so. `--models-from head` lints with the working-tree copy
 instead. Use it for the PR that adds or changes the file; the source label

lib/ship-preflight.ts

@@ -8,6 +8,7 @@
 import * as fs from 'node:fs';
 import * as os from 'node:os';
 import * as path from 'node:path';
+import { defaultBaseBranch } from './default-base';
 import { classifyDiff } from './review-depth';
 import { audit } from './ship-audit';
 import { bin, carryNoneLine, firstLine, flagReader, gh, git, hostedOrigin, laneConcurrency, laneLine, lanes, Report, runLanes, shipPolicy, short } from './ship-bin-common';
@@ -33,14 +34,16 @@ const DIST = /(^|\/)(cmd\/[^/]+\/main\.go|bin\/[^/]+|Cargo\.toml|setup\.py|packa
 
 function integrate(cwd: string, base: string, r: Report): boolean {
   const branch = git(cwd, ['branch', '--show-current']).stdout.trim();
-  const remote = /^ref: refs\/heads\/(\S+)\s+HEAD$/m.exec(git(cwd, ['ls-remote', '--symref', 'origin', 'HEAD'], 60_000).stdout)?.[1];
-  const head = remote ?? git(cwd, ['symbolic-ref', '--short', 'refs/remotes/origin/HEAD']).stdout.trim().replace(/^origin\//, '');
   r.add(`BRANCH: ${branch || '(detached)'} base=${base}`);
-  if (!branch || branch === base || branch === head) { r.stop(`on the base branch (${branch || 'detached HEAD'}): ship from a feature branch`); return false; }
+  if (!branch || branch === base) { r.stop(`on the base branch (${branch || 'detached HEAD'}): ship from a feature branch`); return false; }
   const status = git(cwd, ['status', '--porcelain']).stdout.split('\n').filter(Boolean);
   r.add(`STATUS: modified=${status.filter(l => !l.startsWith('??')).length} untracked=${status.filter(l => l.startsWith('??')).length} (uncommitted changes ship with this run)`);
   const fetch = git(cwd, ['fetch', 'origin', `+refs/heads/${base}:refs/remotes/origin/${base}`], 300_000);
   if (fetch.status !== 0) { r.stop(`git fetch origin ${base} failed: ${firstLine(fetch.stderr)}; restore access first`); return false; }
+  const remoteHead = git(cwd, ['ls-remote', '--symref', 'origin', 'HEAD'], 60_000);
+  if (remoteHead.status !== 0) { r.stop(`git ls-remote origin HEAD failed: ${firstLine(remoteHead.stderr)}; restore access first`); return false; }
+  const head = /^ref: refs\/heads\/(\S+)\s+HEAD$/m.exec(remoteHead.stdout)?.[1] ?? defaultBaseBranch(cwd).branch;
+  if (branch === head) { r.stop(`on the base branch (${branch}): ship from a feature branch`); return false; }
   const stat = git(cwd, ['diff', forkPoint(cwd, base), '--shortstat']).stdout.trim();
   const lines = [...stat.matchAll(/(\d+) (insertion|deletion)/g)].reduce((n, m) => n + Number(m[1]), 0);
   const commits = git(cwd, ['rev-list', '--count', `origin/${base}..HEAD`]).stdout.trim();

package.json

@@ -1,6 +1,6 @@
 {
   "name": "gstack",
-  "version": "1.94.2",
+  "version": "1.94.3",
   "description": "Garry's Stack — Claude Code skills + fast headless browser. One repo, one install, entire AI engineering workflow.",
   "license": "MIT",
   "type": "module",

test/ship-preflight.test.ts

@@ -57,6 +57,50 @@ describe('gstack-ship-preflight', () => {
     expect(r.status).toBe(0);
   });
 
+  // Value: protects=a failed lookup of the remote's HEAD stops with "restore access first" instead of guessing the default branch from a local origin/HEAD;
+  //   fails_when=a failed ls-remote falls back to the local ref, so the default branch with no local origin/HEAD merges another base and goes on, and a feature
+  //   branch a Capy checkout's origin/HEAD names is refused as the base branch; why_new=GST-511 follow-up from #3718; seam=a git wrapper on PATH that fails
+  //   ls-remote only; no_claim=which access failure it was
+  test('a failed remote HEAD lookup stops before merging, even when the fetch works', () => {
+    const f = fx();
+    fs.writeFileSync(path.join(f.root, 'stub', 'git'), `#!/bin/sh\n[ "$1" = ls-remote ] && { echo "ls-remote: unreachable" >&2; exit 128; }\nexec ${Bun.which('git')} "$@"\n`, { mode: 0o755 });
+    f.git('push', '-q', 'origin', 'main:release');
+    f.git('checkout', '-q', 'main');
+    f.git('remote', 'set-head', 'origin', '-d');
+    const onDefault = f.run(PREFLIGHT, ['--base', 'release']);
+    f.git('checkout', '-q', 'feat');
+    f.git('update-ref', 'refs/remotes/origin/feat', 'HEAD');
+    f.git('symbolic-ref', 'refs/remotes/origin/HEAD', 'refs/remotes/origin/feat');
+    const onFeature = f.run(PREFLIGHT, ['--base', 'main']);
+    for (const r of [onDefault, onFeature]) {
+      expect(r.status).toBe(3);
+      expect(r.stdout).toContain('STOP: git ls-remote origin HEAD failed: ls-remote: unreachable; restore access first');
+      expect(r.stdout).not.toContain('MERGE:');
+    }
+  });
+
+  // Value: protects=a remote whose HEAD names no branch (detached, or a server that sends no symref) falls back to the default-base ladder, not the local origin/HEAD;
+  //   fails_when=the fallback reads the local ref, so the default branch with no local origin/HEAD merges another base and goes on, and a feature branch a
+  //   Capy checkout's origin/HEAD names is refused as the base branch; why_new=pass-1 review of the ls-remote stop; seam=a git wrapper whose ls-remote prints
+  //   only a sha; no_claim=a repository whose default is neither main nor master
+  test('with no symbolic remote HEAD, the default branch still stops and a feature branch named by a local origin/HEAD goes on', () => {
+    const f = fx();
+    fs.writeFileSync(path.join(f.root, 'stub', 'git'), `#!/bin/sh\n[ "$1" = ls-remote ] && { echo "0000000000000000000000000000000000000000\tHEAD"; exit 0; }\nexec ${Bun.which('git')} "$@"\n`, { mode: 0o755 });
+    f.git('push', '-q', 'origin', 'main:release');
+    f.git('checkout', '-q', 'main');
+    f.git('remote', 'set-head', 'origin', '-d');
+    const onDefault = f.run(PREFLIGHT, ['--base', 'release']);
+    expect(onDefault.status).toBe(3);
+    expect(onDefault.stdout).toContain('STOP: on the base branch (main)');
+    expect(onDefault.stdout).not.toContain('MERGE:');
+    f.git('checkout', '-q', 'feat');
+    f.git('update-ref', 'refs/remotes/origin/feat', 'HEAD');
+    f.git('symbolic-ref', 'refs/remotes/origin/HEAD', 'refs/remotes/origin/feat');
+    const onFeature = f.run(PREFLIGHT, ['--base', 'main']);
+    expect(onFeature.stdout).not.toContain('STOP: on the base branch');
+    expect(onFeature.status).toBe(0);
+  });
+
   // Value: protects=Step 3 merges the base and a conflict stops with the files named, leaving the merge for the agent to resolve; fails_when=the bin resolves a conflict itself, aborts the merge, or continues to tests;
   //   why_new=moved from the Step 3 prose; seam=git merge; no_claim=which side is right
   test('a merged base is reported; a conflict stops with the conflicted files and the merge left in place', () => {