fix(gateway): harden build workspace boundaries

app/gateway-api/test/buildRunner.test.ts

@@ -0,0 +1,43 @@
+import path from 'node:path';
+
+import { describe, expect, it } from 'vitest';
+
+import { MAX_BUILD_OUTPUT_CHARS, PnpmBuildRunner } from '../src/orchestrator/buildRunner.js';
+
+describe('PnpmBuildRunner', () => {
+    it('returns a failed result when a command cannot be spawned', async () => {
+        const runner = new PnpmBuildRunner();
+
+        const result = await runner.run([
+            {
+                command: path.join(process.cwd(), 'missing-build-command'),
+                args: [],
+                cwd: process.cwd(),
+            },
+        ]);
+
+        expect(result.ok).toBe(false);
+        expect(result.exitCode).toBeNull();
+        expect(result.output).toContain('ENOENT');
+    });
+
+    it('retains only a bounded tail across command output', async () => {
+        const runner = new PnpmBuildRunner();
+        const result = await runner.run([
+            {
+                command: process.execPath,
+                args: ['-e', `process.stdout.write('a'.repeat(${MAX_BUILD_OUTPUT_CHARS}));`],
+                cwd: process.cwd(),
+            },
+            {
+                command: process.execPath,
+                args: ['-e', "process.stdout.write('tail-marker');"],
+                cwd: process.cwd(),
+            },
+        ]);
+
+        expect(result.ok).toBe(true);
+        expect(result.output.length).toBe(MAX_BUILD_OUTPUT_CHARS);
+        expect(result.output.endsWith('tail-marker')).toBe(true);
+    });
+});

app/gateway-api/test/workspaceManager.test.ts

@@ -85,4 +85,65 @@ describe('GitWorkspaceManager source resolution', () => {
         await expect(manager.resolveCommit('BRANCH', '--upload-pack=bad')).rejects.toThrow('Invalid git ref');
         await expect(manager.resolveCommit('COMMIT', 'HEAD..main')).rejects.toThrow('Invalid git ref');
     });
+
+    it('reuses only a clean registered worktree at the requested commit', async () => {
+        const fixture = createRepositoryFixture();
+        const manager = new GitWorkspaceManager({
+            repoRoot: fixture.checkout,
+            worktreeRoot: fixture.worktrees,
+        });
+
+        const created = await manager.prepare(fixture.firstCommit);
+        expect(created.created).toBe(true);
+        const reused = await manager.prepare(fixture.firstCommit);
+        expect(reused).toMatchObject({ root: created.root, created: false });
+
+        fs.writeFileSync(path.join(created.root, 'untracked.txt'), 'dirty\n');
+        await expect(manager.prepare(fixture.firstCommit)).rejects.toThrow('uncommitted changes');
+    });
+
+    it('rejects an unregistered directory that occupies a commit workspace path', async () => {
+        const fixture = createRepositoryFixture();
+        const manager = new GitWorkspaceManager({
+            repoRoot: fixture.checkout,
+            worktreeRoot: fixture.worktrees,
+        });
+        const occupied = path.join(fixture.worktrees, fixture.firstCommit);
+        fs.mkdirSync(occupied, { recursive: true });
+
+        await expect(manager.prepare(fixture.firstCommit)).rejects.toThrow('not registered as a git worktree');
+    });
+
+    it('removes only registered direct commit workspaces and never the root or sibling prefixes', async () => {
+        const fixture = createRepositoryFixture();
+        const manager = new GitWorkspaceManager({
+            repoRoot: fixture.checkout,
+            worktreeRoot: fixture.worktrees,
+        });
+        const workspace = await manager.prepare(fixture.firstCommit);
+        const siblingPrefix = `${fixture.worktrees}-outside`;
+        fs.mkdirSync(siblingPrefix, { recursive: true });
+
+        await expect(manager.remove(fixture.worktrees)).rejects.toThrow('must be a child');
+        await expect(manager.remove(path.join(siblingPrefix, fixture.firstCommit))).rejects.toThrow('must be a child');
+        expect(fs.existsSync(siblingPrefix)).toBe(true);
+        await expect(manager.remove(workspace.root)).resolves.toBe(true);
+        expect(fs.existsSync(workspace.root)).toBe(false);
+    });
+
+    it('rejects deletion of unregistered and nested paths under the worktree root', async () => {
+        const fixture = createRepositoryFixture();
+        const manager = new GitWorkspaceManager({
+            repoRoot: fixture.checkout,
+            worktreeRoot: fixture.worktrees,
+        });
+        const unregistered = path.join(fixture.worktrees, fixture.firstCommit);
+        fs.mkdirSync(unregistered, { recursive: true });
+
+        await expect(manager.remove(unregistered)).rejects.toThrow('not registered as a git worktree');
+        await expect(manager.remove(path.join(unregistered, 'nested'))).rejects.toThrow(
+            'not a managed commit workspace'
+        );
+        expect(fs.existsSync(unregistered)).toBe(true);
+    });
 });