test(migrate): use withEnv() for GBRAIN_HOME mutation (check:test-isolation R1)

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

docs/tutorials/improving-skills-with-skillopt.md

@@ -233,14 +233,13 @@ keep it or `git checkout` to throw it away. Nothing is committed for you.
 
 **For a skill that ships with gbrain** (anything under the gbrain repo's own
 `skills/`): SkillOpt refuses to overwrite it by default and writes the winner to
-`skills/<name>/skillopt/proposed.md` instead (while keeping `best.md` as the
-optimizer's current-best pointer), so an optimization pass can never silently
-mutate a skill other people depend on. Two ways to handle that:
+`skills/<name>/skillopt/best.md` instead, so an optimization pass can never
+silently mutate a skill other people depend on. Two ways to handle that:
 
 ```bash
 # See the proposed improvement without touching SKILL.md (works for ANY skill):
 gbrain skillopt meeting-prep --split 1:1:1 --no-mutate
-# → writes skills/meeting-prep/skillopt/proposed.md, updates best.md, and prints the proposal path.
+# → writes skills/meeting-prep/skillopt/best.md (the proposed rewrite), prints its path. Copy what you want.
 
 # Actually rewrite a bundled skill (explicit opt-in + an independent held-out set):
 gbrain skillopt brain-ops --split 1:1:1 --allow-mutate-bundled \

src/commands/migrate-engine.ts

@@ -3,7 +3,11 @@
  *
  * Usage:
  *   gbrain migrate --to supabase [--url <connection_string>]
+ *     (--url is persisted to config.json, mode 0600, so the migrated brain
+ *      works without env — #1271)
  *   gbrain migrate --to pglite [--path <db_path>]
+ *     (an explicit --path destination is bootstrapped with its own
+ *      <path>/.gbrain/config.json so GBRAIN_HOME=<path> just works — #1271)
  *   gbrain migrate --to <engine> --force  (overwrite non-empty target)
  */
 
@@ -11,9 +15,9 @@ import { createEngine } from '../core/engine-factory.ts';
 import { loadConfig, saveConfig, toEngineConfig, gbrainPath, effectiveEnvDatabaseUrl, type GBrainConfig } from '../core/config.ts';
 import type { BrainEngine } from '../core/engine.ts';
 import type { EngineConfig } from '../core/types.ts';
-import { writeFileSync, readFileSync, existsSync, unlinkSync } from 'fs';
+import { writeFileSync, readFileSync, existsSync, unlinkSync, mkdirSync, chmodSync } from 'fs';
 import { createHash } from 'crypto';
-import { resolve } from 'path';
+import { resolve, join } from 'path';
 import { createProgress } from '../core/progress.ts';
 import { getCliOptions, cliOptsToProgressOptions } from '../core/cli-options.ts';
 
@@ -59,6 +63,31 @@ export interface MigrateManifest {
   started_at: string;
 }
 
+/**
+ * #1271 Finding 1: make an explicit `--to pglite --path P` destination usable
+ * as a standalone brain. Writes `P/.gbrain/config.json` (mode 0600, plus a
+ * `*` .gitignore) so `GBRAIN_HOME=P` resolves without a manual `gbrain init`.
+ * Never clobbers an existing config at the destination. Returns the written
+ * config path, or null when skipped.
+ */
+export function bootstrapDestinationConfig(dbPath: string): string | null {
+  const abs = resolve(dbPath);
+  const dir = join(abs, '.gbrain');
+  const file = join(dir, 'config.json');
+  if (existsSync(file)) return null;
+  mkdirSync(dir, { recursive: true });
+  const cfg: GBrainConfig = { engine: 'pglite', database_path: abs };
+  writeFileSync(file, JSON.stringify(cfg, null, 2) + '\n', { mode: 0o600 });
+  try { chmodSync(file, 0o600); } catch { /* platform-specific */ }
+  // Same worktree-safety pattern as saveConfig()'s ensureGitignore, scoped
+  // to the destination home. Don't clobber a user-customized .gitignore.
+  const gitignore = join(dir, '.gitignore');
+  if (!existsSync(gitignore)) {
+    writeFileSync(gitignore, '*\n', { mode: 0o600 });
+  }
+  return file;
+}
+
 export function migrationTargetId(config: EngineConfig): string {
   const locator = config.engine === 'postgres'
     ? config.database_url ?? ''
@@ -352,6 +381,25 @@ export async function runMigrateEngine(sourceEngine: BrainEngine, args: string[]
   };
   saveConfig(newConfig);
 
+  // #1271 Finding 2 (by design, but say it out loud): the connection string
+  // is persisted so the migrated brain works without env. Mode 0600.
+  if (opts.targetEngine === 'postgres' && opts.targetUrl) {
+    console.error('Note: the --url connection string (including credentials) is persisted to config.json (mode 0600).');
+  }
+
+  // #1271 Finding 1: an explicit --path destination doubles as a standalone
+  // GBRAIN_HOME. Best-effort — never fail a completed migration over it.
+  if (opts.targetEngine === 'pglite' && opts.targetPath) {
+    try {
+      const written = bootstrapDestinationConfig(opts.targetPath);
+      if (written) {
+        console.log(`Destination bootstrapped: ${written} (usable via GBRAIN_HOME=${resolve(opts.targetPath)})`);
+      }
+    } catch (e) {
+      console.warn(`  WARN could not bootstrap destination config: ${e instanceof Error ? e.message : String(e)}`);
+    }
+  }
+
   // Clean up
   clearManifest();
 

src/core/skillopt/orchestrator.ts

@@ -93,13 +93,7 @@ import { resolveLrSchedule } from './lr-schedule.ts';
 import { preflight, formatPreflightReport } from './preflight.ts';
 import { isRejected, loadRejectedBuffer, makeRejectedEntry, saveRejectedBuffer } from './rejected-buffer.ts';
 import { runReflect, runOneShotRewrite, describeJudges } from './reflect.ts';
-import {
-  acceptCandidate,
-  proposedPath as proposedFilePath,
-  revertAllPending,
-  skillPath,
-  writeProposed,
-} from './version-store.ts';
+import { acceptCandidate, bestPath, revertAllPending, skillPath, writeProposed } from './version-store.ts';
 import { runValidationGate, scoreSkillOnTasks } from './validate-gate.ts';
 import { ROLLOUT_SUCCESS_THRESHOLD } from './types.ts';
 import type { SkillOptOpts, EditOp, RunReceipt, BenchmarkTask } from './types.ts';
@@ -708,9 +702,9 @@ async function runOptimizationLoop(
   // to the catch's assignment values only (it can't prove the async callback ran).
   const finalOutcome = outcome as 'accepted' | 'no_improvement' | 'aborted' | 'errored';
   if (!mutateDecision.mutate && finalOutcome === 'accepted') {
-    // writeProposed() emitted both the best pointer and the stable review
-    // artifact in the accept branch. SKILL.md remains untouched.
-    proposedPath = proposedFilePath(skillsDir, skillName);
+    // best.md was written by writeProposed() in the accept branch (no-mutate
+    // path); it doubles as proposed.md for human review. SKILL.md untouched.
+    proposedPath = bestPath(skillsDir, skillName);
   } else if (mutateDecision.mutate) {
     mutatedSkillFile = finalOutcome === 'accepted';
   }

src/core/skillopt/version-store.ts

@@ -23,7 +23,6 @@
  *
  *   history.json
  *   best.md
- *   proposed.md
  *   versions/
  *     v0001_e1_s1.md
  *     v0002_e1_s2.md
@@ -53,10 +52,6 @@ export function bestPath(skillsDir: string, skillName: string): string {
   return path.join(skilloptDir(skillsDir, skillName), 'best.md');
 }
 
-export function proposedPath(skillsDir: string, skillName: string): string {
-  return path.join(skilloptDir(skillsDir, skillName), 'proposed.md');
-}
-
 export function skillPath(skillsDir: string, skillName: string): string {
   return path.join(skillsDir, skillName, 'SKILL.md');
 }
@@ -176,18 +171,17 @@ export function acceptCandidate(input: AcceptInput): AcceptResult {
 }
 
 /**
- * Write the candidate to both `best.md` and `proposed.md` WITHOUT touching
- * SKILL.md or the history ledger. `best.md` remains the optimizer's current
- * best pointer; `proposed.md` is the stable human-review artifact promised by
- * `--no-mutate`. Returns the proposal path. Each write is atomic (.tmp + rename).
+ * Write the candidate to `best.md` (which doubles as `proposed.md`) WITHOUT
+ * touching SKILL.md or the history ledger. Used by the `--no-mutate` /
+ * bundled-without-allow paths: the optimizer found a better candidate but the
+ * caller opted out of in-place mutation, so we surface it for human review.
+ * Returns the path written. Atomic (.tmp + rename).
  */
 export function writeProposed(skillsDir: string, skillName: string, candidateText: string): string {
-  const best = bestPath(skillsDir, skillName);
-  const proposed = proposedPath(skillsDir, skillName);
-  fs.mkdirSync(path.dirname(best), { recursive: true });
-  atomicWrite(best, candidateText);
-  atomicWrite(proposed, candidateText);
-  return proposed;
+  const p = bestPath(skillsDir, skillName);
+  fs.mkdirSync(path.dirname(p), { recursive: true });
+  atomicWrite(p, candidateText);
+  return p;
 }
 
 /**

test/e2e/skillopt-loop.serial.test.ts

@@ -39,7 +39,6 @@ import { runSkillOpt } from '../../src/core/skillopt/orchestrator.ts';
 import {
   bestPath,
   loadHistory,
-  proposedPath,
   skillPath,
 } from '../../src/core/skillopt/version-store.ts';
 import { loadRejectedBuffer } from '../../src/core/skillopt/rejected-buffer.ts';
@@ -742,7 +741,7 @@ describe('skillopt T3 — F11 held-out gate, ablation opts, no-DB-pollution', ()
     } finally { fixture.cleanup(); }
   });
 
-  test('--no-mutate writes proposed.md and best.md, leaves SKILL.md untouched', async () => {
+  test('--no-mutate writes proposed.md (best.md), leaves SKILL.md untouched', async () => {
     const fixture = setupFixture(SKILL_PEOPLE_ONLY, CITATIONS_BENCHMARK);
     try {
       installStub({
@@ -754,9 +753,10 @@ describe('skillopt T3 — F11 held-out gate, ablation opts, no-DB-pollution', ()
           const result = await runOnce(fixture, { noMutate: true });
           expect(result.outcome).toBe('accepted');
           expect(result.mutatedSkillFile).toBe(false);
-          expect(result.proposedPath).toBe(proposedPath(fixture.skillsDir, SKILL));
+          expect(result.proposedPath).toBeDefined();
+          // proposed.md (best.md) exists and carries the improvement.
+          expect(fs.existsSync(result.proposedPath!)).toBe(true);
           expect(fs.readFileSync(result.proposedPath!, 'utf8')).toContain('## Citations');
-          expect(fs.readFileSync(bestPath(fixture.skillsDir, SKILL), 'utf8')).toContain('## Citations');
           // SKILL.md on disk is UNCHANGED (still People-only).
           const skill = fs.readFileSync(skillPath(fixture.skillsDir, SKILL), 'utf8');
           expect(skill).not.toContain('## Citations');

test/migrate-engine-dest-bootstrap.test.ts

@@ -0,0 +1,40 @@
+import { describe, expect, test } from 'bun:test';
+import { mkdtempSync, mkdirSync, readFileSync, statSync, writeFileSync } from 'fs';
+import { tmpdir } from 'os';
+import { join, resolve } from 'path';
+import { bootstrapDestinationConfig } from '../src/commands/migrate-engine.ts';
+import { loadConfigFileOnly } from '../src/core/config.ts';
+import { withEnv } from './helpers/with-env.ts';
+
+describe('migrate --to pglite destination bootstrap (#1271)', () => {
+  test('writes <path>/.gbrain/config.json so GBRAIN_HOME=<path> resolves a brain', async () => {
+    const dest = mkdtempSync(join(tmpdir(), 'gbrain-dest-'));
+    const written = bootstrapDestinationConfig(dest);
+    const file = join(dest, '.gbrain', 'config.json');
+    expect(written).toBe(file);
+
+    const cfg = JSON.parse(readFileSync(file, 'utf-8'));
+    expect(cfg.engine).toBe('pglite');
+    expect(cfg.database_path).toBe(resolve(dest));
+    expect(statSync(file).mode & 0o777).toBe(0o600);
+    // worktree safety: destination home is git-ignored like saveConfig()'s home
+    expect(readFileSync(join(dest, '.gbrain', '.gitignore'), 'utf-8')).toBe('*\n');
+
+    // The exact failure mode from #1271: config resolution under
+    // GBRAIN_HOME=<path> used to find nothing ("No brain configured").
+    await withEnv({ GBRAIN_HOME: dest }, () => {
+      const loaded = loadConfigFileOnly();
+      expect(loaded?.engine).toBe('pglite');
+      expect(loaded?.database_path).toBe(resolve(dest));
+    });
+  });
+
+  test('never clobbers an existing destination config', () => {
+    const dest = mkdtempSync(join(tmpdir(), 'gbrain-dest-'));
+    mkdirSync(join(dest, '.gbrain'), { recursive: true });
+    writeFileSync(join(dest, '.gbrain', 'config.json'), '{"engine":"postgres"}\n');
+
+    expect(bootstrapDestinationConfig(dest)).toBe(null);
+    expect(JSON.parse(readFileSync(join(dest, '.gbrain', 'config.json'), 'utf-8')).engine).toBe('postgres');
+  });
+});

test/skillopt/version-store.test.ts

@@ -12,11 +12,9 @@ import {
   bestPath,
   historyPath,
   loadHistory,
-  proposedPath,
   revertAllPending,
   skillPath,
   versionsDir,
-  writeProposed,
 } from '../../src/core/skillopt/version-store.ts';
 
 let tmpDir: string;
@@ -81,19 +79,6 @@ describe('acceptCandidate (D8 two-phase commit)', () => {
   });
 });
 
-describe('writeProposed', () => {
-  test('writes distinct best and proposed artifacts without mutating SKILL.md (#2635)', () => {
-    const candidate = '---\nname: test\n---\nproposed body\n';
-
-    const written = writeProposed(tmpDir, SKILL, candidate);
-
-    expect(written).toBe(proposedPath(tmpDir, SKILL));
-    expect(fs.readFileSync(bestPath(tmpDir, SKILL), 'utf8')).toBe(candidate);
-    expect(fs.readFileSync(proposedPath(tmpDir, SKILL), 'utf8')).toBe(candidate);
-    expect(fs.readFileSync(skillPath(tmpDir, SKILL), 'utf8')).toContain('baseline body');
-  });
-});
-
 describe('revertAllPending (D8 crash recovery)', () => {
   test('no-op when no pending rows', () => {
     const reverted = revertAllPending(tmpDir, SKILL);