feat: do not use a git stash for better performance

lib/gitWorkflow.js

@@ -9,7 +9,6 @@ const {
   GitError,
   RestoreOriginalStateError,
   ApplyEmptyCommitError,
-  GetBackupStashError,
   HideUnstagedChangesError,
   RestoreMergeStatusError,
   RestoreUnstagedChangesError,
@@ -41,8 +40,6 @@ const processRenames = (files, includeRenameFrom = true) =>
     return flattened
   }, [])
 
-const STASH = 'lint-staged automatic backup'
-
 const PATCH_UNSTAGED = 'lint-staged_unstaged.patch'
 
 const GIT_DIFF_ARGS = [
@@ -90,19 +87,6 @@ class GitWorkflow {
     return path.resolve(this.gitConfigDir, `./${filename}`)
   }
 
-  /**
-   * Get name of backup stash
-   */
-  async getBackupStash(ctx) {
-    const stashes = await this.execGit(['stash', 'list'])
-    const index = stashes.split('\n').findIndex((line) => line.includes(STASH))
-    if (index === -1) {
-      ctx.errors.add(GetBackupStashError)
-      throw new Error('lint-staged automatic backup is missing!')
-    }
-    return `refs/stash@{${index}}`
-  }
-
   /**
    * Get a list of unstaged deleted files
    */
@@ -184,7 +168,7 @@ class GitWorkflow {
   }
 
   /**
-   * Create a diff of partially staged files and backup stash if enabled.
+   * Create a diff of partially staged files.
    */
   async prepare(ctx) {
     try {
@@ -203,25 +187,6 @@ class GitWorkflow {
         ctx.hasPartiallyStagedFiles = false
       }
 
-      /**
-       * If backup stash should be skipped, no need to continue
-       */
-      if (!ctx.shouldBackup) return
-
-      // When backup is enabled, the revert will clear ongoing merge status.
-      await this.backupMergeStatus()
-
-      // Get a list of unstaged deleted files, because certain bugs might cause them to reappear:
-      // - in git versions =< 2.13.0 the `git stash --keep-index` option resurrects deleted files
-      // - git stash can't infer RD or MD states correctly, and will lose the deletion
-      this.deletedFiles = await this.getDeletedFiles()
-
-      // Save stash of all staged files.
-      // The `stash create` command creates a dangling commit without removing any files,
-      // and `stash store` saves it as an actual stash.
-      const hash = await this.execGit(['stash', 'create'])
-      await this.execGit(['stash', 'store', '--quiet', '--message', STASH, hash])
-
       debug('Done backing up original state!')
     } catch (error) {
       handleError(error, ctx)
@@ -245,9 +210,26 @@ class GitWorkflow {
   }
 
   /**
-   * Applies back task modifications, and unstaged changes hidden in the stash.
-   * In case of a merge-conflict retry with 3-way merge.
+   * Restore original HEAD state for partially staged files in case of errors
    */
+  async restorePartiallyStagedFiles(ctx) {
+    try {
+      debug('Restoring original state...')
+
+      // Flush all unstaged changes. Since they were diffed before
+      // running tasks, these will include only changes generated by tasks
+      await this.hideUnstagedChanges(ctx)
+
+      const unstagedPatch = this.getHiddenFilepath(PATCH_UNSTAGED)
+      await this.execGit(['apply', ...GIT_APPLY_ARGS, unstagedPatch])
+
+      debug('Done restoring original state!')
+    } catch (error) {
+      handleError(error, ctx, RestoreOriginalStateError)
+    }
+  }
+
+  /** Add all task modifications to index for files that were staged before running. */
   async applyModifications(ctx) {
     debug('Adding task modifications to index...')
 
@@ -299,37 +281,13 @@ class GitWorkflow {
   }
 
   /**
-   * Restore original HEAD state in case of errors
-   */
-  async restoreOriginalState(ctx) {
-    try {
-      debug('Restoring original state...')
-      await this.execGit(['reset', '--hard', 'HEAD'])
-      await this.execGit(['stash', 'apply', '--quiet', '--index', await this.getBackupStash(ctx)])
-
-      // Restore meta information about ongoing git merge
-      await this.restoreMergeStatus(ctx)
-
-      // If stashing resurrected deleted files, clean them out
-      await Promise.all(this.deletedFiles.map((file) => unlink(file)))
-
-      // Clean out patch
-      await unlink(this.getHiddenFilepath(PATCH_UNSTAGED))
-
-      debug('Done restoring original state!')
-    } catch (error) {
-      handleError(error, ctx, RestoreOriginalStateError)
-    }
-  }
-
-  /**
-   * Drop the created stashes after everything has run
+   * Drop the created diff file after everything has run
    */
   async cleanup(ctx) {
     try {
-      debug('Dropping backup stash...')
-      await this.execGit(['stash', 'drop', '--quiet', await this.getBackupStash(ctx)])
-      debug('Done dropping backup stash!')
+      debug('Removing temp files...')
+      await unlink(this.getHiddenFilepath(PATCH_UNSTAGED))
+      debug('Done removing temp files!')
     } catch (error) {
       handleError(error, ctx)
     }

lib/index.js

@@ -4,15 +4,10 @@ const { cosmiconfig } = require('cosmiconfig')
 const debugLog = require('debug')('lint-staged')
 const stringifyObject = require('stringify-object')
 
-const { PREVENTED_EMPTY_COMMIT, GIT_ERROR, RESTORE_STASH_EXAMPLE } = require('./messages')
+const { PREVENTED_EMPTY_COMMIT, GIT_ERROR } = require('./messages')
 const printTaskOutput = require('./printTaskOutput')
 const runAll = require('./runAll')
-const {
-  ApplyEmptyCommitError,
-  ConfigNotFoundError,
-  GetBackupStashError,
-  GitError,
-} = require('./symbols')
+const { ApplyEmptyCommitError, ConfigNotFoundError, GitError } = require('./symbols')
 const validateConfig = require('./validateConfig')
 const validateOptions = require('./validateOptions')
 
@@ -140,12 +135,8 @@ const lintStaged = async (
       const { ctx } = runAllError
       if (ctx.errors.has(ApplyEmptyCommitError)) {
         logger.warn(PREVENTED_EMPTY_COMMIT)
-      } else if (ctx.errors.has(GitError) && !ctx.errors.has(GetBackupStashError)) {
+      } else if (ctx.errors.has(GitError)) {
         logger.error(GIT_ERROR)
-        if (ctx.shouldBackup) {
-          // No sense to show this if the backup stash itself is missing.
-          logger.error(RESTORE_STASH_EXAMPLE)
-        }
       }
 
       printTaskOutput(ctx, logger)

lib/messages.js

@@ -57,13 +57,6 @@ const PREVENTED_EMPTY_COMMIT = `
   Use the --allow-empty option to continue, or check your task configuration`)}
 `
 
-const RESTORE_STASH_EXAMPLE = `  Any lost modifications can be restored from a git stash:
-
-    > git stash list
-    stash@{0}: automatic lint-staged backup
-    > git stash apply --index stash@{0}
-`
-
 const CONFIG_STDIN_ERROR = 'Error: Could not read config from stdin.'
 
 module.exports = {
@@ -78,7 +71,6 @@ module.exports = {
   NO_TASKS,
   NOT_GIT_REPO,
   PREVENTED_EMPTY_COMMIT,
-  RESTORE_STASH_EXAMPLE,
   SKIPPED_GIT_ERROR,
   skippingBackup,
   TASK_ERROR,

lib/runAll.js

@@ -219,6 +219,12 @@ const runAll = async (
         enabled: hasPartiallyStagedFiles,
       },
       ...listrTasks,
+      {
+        title: 'Reverting to original state because of errors...',
+        task: (ctx) => git.restorePartiallyStagedFiles(ctx),
+        enabled: restoreOriginalStateEnabled,
+        skip: restoreOriginalStateSkipped,
+      },
       {
         title: 'Applying modifications...',
         task: (ctx) => git.applyModifications(ctx),
@@ -230,12 +236,6 @@ const runAll = async (
         enabled: hasPartiallyStagedFiles,
         skip: restoreUnstagedChangesSkipped,
       },
-      {
-        title: 'Reverting to original state because of errors...',
-        task: (ctx) => git.restoreOriginalState(ctx),
-        enabled: restoreOriginalStateEnabled,
-        skip: restoreOriginalStateSkipped,
-      },
       {
         title: 'Cleaning up...',
         task: (ctx) => git.cleanup(ctx),

lib/state.js

@@ -43,11 +43,7 @@ const restoreUnstagedChangesSkipped = (ctx) => {
   }
 }
 
-const restoreOriginalStateEnabled = (ctx) =>
-  ctx.shouldBackup &&
-  (ctx.errors.has(TaskError) ||
-    ctx.errors.has(ApplyEmptyCommitError) ||
-    ctx.errors.has(RestoreUnstagedChangesError))
+const restoreOriginalStateEnabled = (ctx) => ctx.shouldBackup && ctx.errors.has(TaskError)
 
 const restoreOriginalStateSkipped = (ctx) => {
   // Should be skipped in case of unknown git errors

lib/symbols.js

@@ -2,7 +2,6 @@
 
 const ApplyEmptyCommitError = Symbol('ApplyEmptyCommitError')
 const ConfigNotFoundError = new Error('Config could not be found')
-const GetBackupStashError = Symbol('GetBackupStashError')
 const GetStagedFilesError = Symbol('GetStagedFilesError')
 const GitError = Symbol('GitError')
 const GitRepoError = Symbol('GitRepoError')
@@ -16,7 +15,6 @@ const TaskError = Symbol('TaskError')
 module.exports = {
   ApplyEmptyCommitError,
   ConfigNotFoundError,
-  GetBackupStashError,
   GetStagedFilesError,
   GitError,
   GitRepoError,