feat: add autoFix runner with lint/test command execution

Implements AutoFixRunner (Task 2) - executes lint and test shell commands
sequentially, short-circuits on lint failure, handles timeouts, and
produces structured AutoFixResult with AI-friendly error summaries.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/services/autoFix/autoFixRunner.test.ts

@@ -0,0 +1,95 @@
+import { afterEach, beforeEach, describe, expect, mock, test } from 'bun:test'
+import {
+  runAutoFixCheck,
+  type AutoFixResult,
+  type AutoFixCheckOptions,
+} from './autoFixRunner.js'
+
+describe('runAutoFixCheck', () => {
+  test('returns success when lint command exits 0', async () => {
+    const result = await runAutoFixCheck({
+      lint: 'echo "all clean"',
+      timeout: 5000,
+      cwd: '/tmp',
+    })
+    expect(result.hasErrors).toBe(false)
+    expect(result.lintOutput).toContain('all clean')
+    expect(result.testOutput).toBeUndefined()
+  })
+
+  test('returns errors when lint command exits non-zero', async () => {
+    const result = await runAutoFixCheck({
+      lint: 'echo "error: unused var" && exit 1',
+      timeout: 5000,
+      cwd: '/tmp',
+    })
+    expect(result.hasErrors).toBe(true)
+    expect(result.lintOutput).toContain('unused var')
+    expect(result.lintExitCode).toBe(1)
+  })
+
+  test('returns errors when test command exits non-zero', async () => {
+    const result = await runAutoFixCheck({
+      test: 'echo "FAIL test_foo" && exit 1',
+      timeout: 5000,
+      cwd: '/tmp',
+    })
+    expect(result.hasErrors).toBe(true)
+    expect(result.testOutput).toContain('FAIL test_foo')
+    expect(result.testExitCode).toBe(1)
+  })
+
+  test('runs both lint and test commands', async () => {
+    const result = await runAutoFixCheck({
+      lint: 'echo "lint ok"',
+      test: 'echo "test ok"',
+      timeout: 5000,
+      cwd: '/tmp',
+    })
+    expect(result.hasErrors).toBe(false)
+    expect(result.lintOutput).toContain('lint ok')
+    expect(result.testOutput).toContain('test ok')
+  })
+
+  test('skips test if lint fails', async () => {
+    const result = await runAutoFixCheck({
+      lint: 'echo "lint error" && exit 1',
+      test: 'echo "should not run"',
+      timeout: 5000,
+      cwd: '/tmp',
+    })
+    expect(result.hasErrors).toBe(true)
+    expect(result.lintOutput).toContain('lint error')
+    expect(result.testOutput).toBeUndefined()
+  })
+
+  test('handles timeout gracefully', async () => {
+    const result = await runAutoFixCheck({
+      lint: 'sleep 10',
+      timeout: 100,
+      cwd: '/tmp',
+    })
+    expect(result.hasErrors).toBe(true)
+    expect(result.timedOut).toBe(true)
+  })
+
+  test('returns success with no commands configured', async () => {
+    const result = await runAutoFixCheck({
+      timeout: 5000,
+      cwd: '/tmp',
+    })
+    expect(result.hasErrors).toBe(false)
+  })
+
+  test('formats error summary for AI consumption', async () => {
+    const result = await runAutoFixCheck({
+      lint: 'echo "src/foo.ts:10:5 error no-unused-vars" && exit 1',
+      timeout: 5000,
+      cwd: '/tmp',
+    })
+    expect(result.hasErrors).toBe(true)
+    const summary = result.errorSummary
+    expect(summary).toContain('Lint errors')
+    expect(summary).toContain('no-unused-vars')
+  })
+})

src/services/autoFix/autoFixRunner.ts

@@ -0,0 +1,135 @@
+import { spawn } from 'child_process'
+
+export interface AutoFixCheckOptions {
+  lint?: string
+  test?: string
+  timeout: number
+  cwd: string
+  signal?: AbortSignal
+}
+
+export interface AutoFixResult {
+  hasErrors: boolean
+  lintOutput?: string
+  lintExitCode?: number
+  testOutput?: string
+  testExitCode?: number
+  timedOut?: boolean
+  errorSummary?: string
+}
+
+async function runCommand(
+  command: string,
+  cwd: string,
+  timeout: number,
+  signal?: AbortSignal,
+): Promise<{ stdout: string; stderr: string; exitCode: number; timedOut: boolean }> {
+  return new Promise((resolve) => {
+    let timedOut = false
+    let stdout = ''
+    let stderr = ''
+
+    const proc = spawn('bash', ['-c', command], {
+      cwd,
+      env: { ...process.env },
+    })
+
+    proc.stdout?.on('data', (data: Buffer) => {
+      stdout += data.toString()
+    })
+    proc.stderr?.on('data', (data: Buffer) => {
+      stderr += data.toString()
+    })
+
+    const timer = setTimeout(() => {
+      timedOut = true
+      proc.kill('SIGTERM')
+    }, timeout)
+
+    proc.on('close', (code) => {
+      clearTimeout(timer)
+      resolve({
+        stdout: stdout.slice(0, 10000),
+        stderr: stderr.slice(0, 10000),
+        exitCode: code ?? 1,
+        timedOut,
+      })
+    })
+
+    proc.on('error', () => {
+      clearTimeout(timer)
+      resolve({
+        stdout,
+        stderr: stderr || 'Command failed to start',
+        exitCode: 1,
+        timedOut: false,
+      })
+    })
+  })
+}
+
+function buildErrorSummary(result: AutoFixResult): string | undefined {
+  if (!result.hasErrors) return undefined
+  const parts: string[] = []
+
+  if (result.timedOut) {
+    parts.push('Command timed out.')
+  }
+  if (result.lintExitCode !== undefined && result.lintExitCode !== 0) {
+    parts.push(`Lint errors (exit code ${result.lintExitCode}):\n${result.lintOutput ?? ''}`)
+  }
+  if (result.testExitCode !== undefined && result.testExitCode !== 0) {
+    parts.push(`Test failures (exit code ${result.testExitCode}):\n${result.testOutput ?? ''}`)
+  }
+
+  return parts.join('\n\n')
+}
+
+export async function runAutoFixCheck(
+  options: AutoFixCheckOptions,
+): Promise<AutoFixResult> {
+  const { lint, test, timeout, cwd, signal } = options
+
+  if (!lint && !test) {
+    return { hasErrors: false }
+  }
+
+  const result: AutoFixResult = { hasErrors: false }
+
+  // Run lint first
+  if (lint) {
+    const lintResult = await runCommand(lint, cwd, timeout, signal)
+    result.lintOutput = (lintResult.stdout + '\n' + lintResult.stderr).trim()
+    result.lintExitCode = lintResult.exitCode
+
+    if (lintResult.timedOut) {
+      result.hasErrors = true
+      result.timedOut = true
+      result.errorSummary = buildErrorSummary(result)
+      return result
+    }
+
+    if (lintResult.exitCode !== 0) {
+      result.hasErrors = true
+      result.errorSummary = buildErrorSummary(result)
+      return result
+    }
+  }
+
+  // Run tests only if lint passed (or no lint configured)
+  if (test) {
+    const testResult = await runCommand(test, cwd, timeout, signal)
+    result.testOutput = (testResult.stdout + '\n' + testResult.stderr).trim()
+    result.testExitCode = testResult.exitCode
+
+    if (testResult.timedOut) {
+      result.hasErrors = true
+      result.timedOut = true
+    } else if (testResult.exitCode !== 0) {
+      result.hasErrors = true
+    }
+  }
+
+  result.errorSummary = buildErrorSummary(result)
+  return result
+}