fix(node): preserve failed transaction rollbacks

sdks/node/src/plugins/managed-installation.ts

@@ -29,7 +29,8 @@ interface FileChange {
 interface StagedChange {
   readonly change: FileChange;
   readonly temporaryPath: string;
-  readonly rollbackPath?: string;
+  rollbackPath?: string;
+  committedSnapshot?: FileSnapshot;
   committed: boolean;
 }
 export interface ManagedRuntimePaths {
@@ -361,16 +362,63 @@ async function commit(
   await assertUnchanged(staged.change, displayName);
   await renameFile(staged.temporaryPath, staged.change.filePath);
   staged.committed = true;
+  const current = await readPhysicalFile(
+    staged.change.filePath,
+    staged.change.label,
+    staged.change.maximumBytes,
+  );
+  if (!current || current.contents !== staged.change.next) {
+    throw new Error(
+      `${staged.change.label} changed immediately after commit: ${staged.change.filePath}`,
+    );
+  }
+  staged.committedSnapshot = current;
+}
+
+async function assertCommittedUnchanged(staged: StagedChange): Promise<void> {
+  const current = await readPhysicalFile(
+    staged.change.filePath,
+    staged.change.label,
+    staged.change.maximumBytes,
+  );
+  const committed = staged.committedSnapshot;
+  if (!current || !committed
+    || current.contents !== committed.contents
+    || current.device !== committed.device
+    || current.inode !== committed.inode) {
+    throw new Error(
+      `${staged.change.label} changed during transaction recovery: ${staged.change.filePath}`,
+    );
+  }
+}
+
+function preserveRollback(staged: StagedChange, cause: unknown): Error {
+  if (!staged.rollbackPath) return asError(cause);
+  const rollbackPath = staged.rollbackPath;
+  staged.rollbackPath = undefined;
+  return new Error(
+    `${errorMessage(cause)}; original content preserved at ${rollbackPath}`,
+    { cause: asError(cause) },
+  );
 }
 
 async function rollback(staged: StagedChange, renameFile: RenameFile): Promise<void> {
   if (!staged.committed) return;
+  try {
+    await assertCommittedUnchanged(staged);
+  } catch (error) {
+    throw preserveRollback(staged, error);
+  }
   if (!staged.change.original) {
     await unlinkOptional(staged.change.filePath);
     return;
   }
   if (!staged.rollbackPath) throw new Error(`Missing rollback data for ${staged.change.label}`);
-  await renameFile(staged.rollbackPath, staged.change.filePath);
+  try {
+    await renameFile(staged.rollbackPath, staged.change.filePath);
+  } catch (error) {
+    throw preserveRollback(staged, error);
+  }
 }
 
 async function cleanup(staged: StagedChange): Promise<void> {

sdks/node/test/codex-transaction.test.mjs

@@ -43,6 +43,15 @@ async function assertNoTransactionFiles(fixture) {
   assert.equal(names.some((name) => /\.(tmp|rollback)$/.test(name)), false);
 }
 
+async function preservedRollback(fixture, basename) {
+  const entries = await readdir(fixture.agentDir);
+  const matches = entries.filter(
+    (name) => name.startsWith(`.${basename}.`) && name.endsWith('.rollback'),
+  );
+  assert.equal(matches.length, 1, entries.join(', '));
+  return path.join(fixture.agentDir, matches[0]);
+}
+
 test('Codex rolls back all five files when a transaction commit fails', async () => {
   const fixture = await createFixture();
   try {
@@ -131,6 +140,102 @@ test('Codex detects concurrent hook changes before committing runtime updates',
   }
 });
 
+test('managed installation preserves rollback data after a committed file changes', async () => {
+  const fixture = await createFixture();
+  try {
+    assert.equal((await fixture.install()).code, 0);
+    const original = await readFile(fixture.guardScriptPath, 'utf-8');
+    const source = `
+      import { rename, rm, writeFile } from 'node:fs/promises';
+      import { readDocument } from ${JSON.stringify(ioModuleUrl)};
+      import {
+        commitCodexInstallation,
+        prepareCodexInstallation,
+      } from ${JSON.stringify(installationModuleUrl)};
+      const document = await readDocument();
+      const prepared = await prepareCodexInstallation(
+        JSON.parse(process.env.ELYDORA_INSTALL_CONFIG),
+        { document, changed: false },
+      );
+      let calls = 0;
+      await commitCodexInstallation(prepared, async (from, to) => {
+        calls += 1;
+        if (calls === 1) {
+          await rename(from, to);
+          await rm(to);
+          await writeFile(to, 'external change\\n');
+          return;
+        }
+        if (calls === 2) throw new Error('injected later commit failure');
+        await rename(from, to);
+      });
+    `;
+    const result = await runNode(
+      ['--input-type=module', '--eval', source],
+      {
+        HOME: fixture.homeDir,
+        USERPROFILE: fixture.homeDir,
+        ELYDORA_INSTALL_CONFIG: JSON.stringify(installConfig(fixture, { orgId: 'updated' })),
+      },
+      fixture.projectDir,
+    );
+    assert.equal(result.code, 1);
+    assert.match(result.stderr, /original content preserved at/i);
+    assert.equal(await readFile(fixture.guardScriptPath, 'utf-8'), 'external change\n');
+    assert.equal(await readFile(
+      await preservedRollback(fixture, 'guard.js'),
+      'utf-8',
+    ), original);
+  } finally {
+    await fixture.close();
+  }
+});
+
+test('managed installation preserves rollback data after restore rename failure', async () => {
+  const fixture = await createFixture();
+  try {
+    assert.equal((await fixture.install()).code, 0);
+    const original = await readFile(fixture.guardScriptPath, 'utf-8');
+    const source = `
+      import { rename } from 'node:fs/promises';
+      import { readDocument } from ${JSON.stringify(ioModuleUrl)};
+      import {
+        commitCodexInstallation,
+        prepareCodexInstallation,
+      } from ${JSON.stringify(installationModuleUrl)};
+      const document = await readDocument();
+      const prepared = await prepareCodexInstallation(
+        JSON.parse(process.env.ELYDORA_INSTALL_CONFIG),
+        { document, changed: false },
+      );
+      let calls = 0;
+      await commitCodexInstallation(prepared, async (from, to) => {
+        calls += 1;
+        if (calls === 2) throw new Error('injected later commit failure');
+        if (from.endsWith('.rollback')) throw new Error('injected rollback failure');
+        await rename(from, to);
+      });
+    `;
+    const result = await runNode(
+      ['--input-type=module', '--eval', source],
+      {
+        HOME: fixture.homeDir,
+        USERPROFILE: fixture.homeDir,
+        ELYDORA_INSTALL_CONFIG: JSON.stringify(installConfig(fixture, { orgId: 'updated' })),
+      },
+      fixture.projectDir,
+    );
+    assert.equal(result.code, 1);
+    assert.match(result.stderr, /original content preserved at/i);
+    assert.equal(await readFile(
+      await preservedRollback(fixture, 'guard.js'),
+      'utf-8',
+    ), original);
+  } finally {
+    await fixture.close();
+  }
+});
+
 test('Codex rejects a stale hook document before staging files', async () => {
   const fixture = await createFixture();
   try {