fix: correctly recover when unstaged changes cannot be restored

lib/gitWorkflow.js

@@ -31,6 +31,14 @@ const cleanUntrackedFiles = async execGit => {
   }
 }
 
+const handleGitLockError = (error, ctx) => {
+  if (error.message.includes('Another git process seems to be running in this repository')) {
+    ctx.hasErrors = true
+    ctx.hasGitLockError = true
+  }
+  throw error
+}
+
 class GitWorkflow {
   constructor({ gitDir, stagedFileChunks }) {
     this.execGit = (args, options = {}) => execGit(args, { ...options, cwd: gitDir })
@@ -129,7 +137,7 @@ class GitWorkflow {
    * Applies back task modifications, and unstaged changes hidden in the stash.
    * In case of a merge-conflict retry with 3-way merge.
    */
-  async applyModifications() {
+  async applyModifications(ctx) {
     let modifiedFiles = await this.execGit(['ls-files', '--modified'])
     if (modifiedFiles) {
       debug('Detected files modified by tasks:')
@@ -158,6 +166,7 @@ class GitWorkflow {
         } catch (error2) {
           debug('Error while restoring unstaged changes using 3-way merge:')
           debug(error2)
+          ctx.hasErrors = true
           throw new Error('Unstaged changes could not be restored due to a merge conflict!')
         }
       }
@@ -179,16 +188,20 @@ class GitWorkflow {
   /**
    * Restore original HEAD state in case of errors
    */
-  async restoreOriginalState() {
-    debug('Restoring original state...')
-    const backupStash = await this.getBackupStash()
-    await this.execGit(['reset', '--hard', 'HEAD'])
-    await this.execGit(['stash', 'apply', '--quiet', '--index', backupStash])
-    debug('Done restoring original state!')
+  async restoreOriginalState(ctx) {
+    try {
+      debug('Restoring original state...')
+      const backupStash = await this.getBackupStash()
+      await this.execGit(['reset', '--hard', 'HEAD'])
+      await this.execGit(['stash', 'apply', '--quiet', '--index', backupStash])
+      debug('Done restoring original state!')
 
-    // Restore meta information about ongoing git merge
-    if (this.mergeHeadBuffer) {
-      await this.restoreMergeStatus()
+      // Restore meta information about ongoing git merge
+      if (this.mergeHeadBuffer) {
+        await this.restoreMergeStatus()
+      }
+    } catch (error) {
+      handleGitLockError(error, ctx)
     }
   }
 

lib/runAll.js

@@ -73,6 +73,7 @@ module.exports = async function runAll(
 
   const listrOptions = {
     dateFormat: false,
+    exitOnError: false,
     renderer: (quiet && 'silent') || (debug && 'verbose') || 'update'
   }
 
@@ -115,7 +116,7 @@ module.exports = async function runAll(
       // No need to show number of task chunks when there's only one
       title:
         chunkCount > 1 ? `Running tasks (chunk ${index + 1}/${chunkCount})...` : 'Running tasks...',
-      task: () => new Listr(chunkListrTasks, { ...listrOptions, concurrent, exitOnError: false }),
+      task: () => new Listr(chunkListrTasks, { ...listrOptions, concurrent }),
       skip: () => {
         if (chunkListrTasks.every(task => task.skip())) {
           return 'No tasks to run.'
@@ -151,15 +152,16 @@ module.exports = async function runAll(
       {
         title: 'Applying modifications...',
         skip: ctx => ctx.hasErrors && 'Skipped because of errors from tasks',
-        task: () => git.applyModifications()
+        task: ctx => git.applyModifications(ctx)
       },
       {
         title: 'Reverting to original state...',
         enabled: ctx => ctx.hasErrors,
-        task: () => git.restoreOriginalState()
+        task: ctx => git.restoreOriginalState(ctx)
       },
       {
         title: 'Cleaning up...',
+        skip: ctx => ctx.hasGitLockError && 'Skipped because of previous git error',
         task: () => git.dropBackup()
       }
     ],
@@ -169,7 +171,7 @@ module.exports = async function runAll(
   try {
     await runner.run()
   } catch (error) {
-    if (error.message.includes('Another git process seems to be running in this repository')) {
+    if (error.context.hasGitLockError) {
       logger.error(`
   ${symbols.error} ${chalk.red(`lint-staged failed due to a git error.
     Any lost modifications can be restored from a git stash:

test/index2.spec.js

@@ -21,7 +21,11 @@ describe('lintStaged', () => {
       { configPath: path.join(__dirname, '__mocks__', 'my-config.json'), quiet: true },
       console
     )
-    expect(Listr.mock.calls[0][1]).toEqual({ dateFormat: false, renderer: 'silent' })
+    expect(Listr.mock.calls[0][1]).toEqual({
+      dateFormat: false,
+      exitOnError: false,
+      renderer: 'silent'
+    })
   })
 
   it('should pass debug flag to Listr', async () => {
@@ -33,6 +37,10 @@ describe('lintStaged', () => {
       },
       console
     )
-    expect(Listr.mock.calls[0][1]).toEqual({ dateFormat: false, renderer: 'verbose' })
+    expect(Listr.mock.calls[0][1]).toEqual({
+      dateFormat: false,
+      exitOnError: false,
+      renderer: 'verbose'
+    })
   })
 })

test/runAll.unmocked.spec.js

@@ -70,7 +70,7 @@ const execGit = async args => execGitBase(args, { cwd })
 
 // Execute runAll before git commit to emulate lint-staged
 const gitCommit = async (options, args = ['-m test']) => {
-  await runAll({ ...options, cwd, quiet: true })
+  await runAll({ quiet: true, ...options, cwd })
   await execGit(['commit', ...args])
 }
 
@@ -191,6 +191,38 @@ describe('runAll', () => {
     expect(await readFile('test.js')).toEqual(testJsFileUnfixable)
   })
 
+  it('Should fail to commit entire staged file when there are unrecoverable merge conflicts', async () => {
+    // Stage file
+    await appendFile('test.js', testJsFileUgly)
+    await execGit(['add', 'test.js'])
+
+    // Run lint-staged with action that does horrible things to the file, causing a merge conflict
+    await expect(
+      gitCommit({
+        config: {
+          '*.js': file => {
+            fs.writeFileSync(file[0], Buffer.from(testJsFileUnfixable, 'binary'))
+            return `prettier --write ${file[0]}`
+          }
+        },
+        quiet: false,
+        debug: true
+      })
+    ).rejects.toThrowError()
+
+    expect(console.printHistory()).toMatch(
+      'Unstaged changes could not be restored due to a merge conflict!'
+    )
+
+    // Something was wrong so the repo is returned to original state
+    expect(await execGit(['rev-list', '--count', 'HEAD'])).toEqual('1')
+    expect(await execGit(['log', '-1', '--pretty=%B'])).toMatch('initial commit')
+    // Git status is a bit messed up because the horrible things we did
+    // in the config above were done before creating the initial backup stash,
+    // and thus included in it.
+    expect(await execGit(['status', '--porcelain'])).toMatchInlineSnapshot(`"AM test.js"`)
+  })
+
   it('Should commit partial change from partially staged file when no errors from linter', async () => {
     // Stage pretty file
     await appendFile('test.js', testJsFilePretty)
@@ -334,9 +366,9 @@ describe('runAll', () => {
     const diff = await execGit(['diff'])
 
     // Run lint-staged with `prettier --write` and commit pretty file
-    // The task creates a git lock file to simulate failure
-    try {
-      await gitCommit({
+    // The task creates a git lock file and runs `git add` to simulate failure
+    await expect(
+      gitCommit({
         config: {
           '*.js': files => [
             `touch ${cwd}/.git/index.lock`,
@@ -345,22 +377,20 @@ describe('runAll', () => {
           ]
         }
       })
-    } catch (error) {
-      expect(error.message).toMatch('Another git process seems to be running in this repository')
-      expect(console.printHistory()).toMatchInlineSnapshot(`
-        "
-        WARN ‼ Some of your tasks use \`git add\` command. Please remove it from the config since all modifications made by tasks will be automatically added to the git commit index.
-
-        ERROR 
-          × lint-staged failed due to a git error.
-            Any lost modifications can be restored from a git stash:
-
-            > git stash list
-            stash@{0}: On master: automatic lint-staged backup
-            > git stash pop stash@{0}
-        "
-      `)
-    }
+    ).rejects.toThrowError()
+    expect(console.printHistory()).toMatchInlineSnapshot(`
+      "
+      WARN ‼ Some of your tasks use \`git add\` command. Please remove it from the config since all modifications made by tasks will be automatically added to the git commit index.
+
+      ERROR 
+        × lint-staged failed due to a git error.
+          Any lost modifications can be restored from a git stash:
+
+          > git stash list
+          stash@{0}: On master: automatic lint-staged backup
+          > git stash pop stash@{0}
+      "
+    `)
 
     // Something was wrong so new commit wasn't created
     expect(await execGit(['rev-list', '--count', 'HEAD'])).toEqual('1')