From c7d05922b24524707795c4045339801c86affe9d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Iiro=20Ja=CC=88ppinen?= <iiro@jappinen.fi>
Date: Tue, 29 Oct 2019 13:16:09 +0200
Subject: [PATCH] fix: correctly restore untracked files from backup stash

---
 lib/gitWorkflow.js | 49 ++++++++++------------------------------------
 1 file changed, 10 insertions(+), 39 deletions(-)

diff --git a/lib/gitWorkflow.js b/lib/gitWorkflow.js
index 5a1020059..05dc198ce 100644
--- a/lib/gitWorkflow.js
+++ b/lib/gitWorkflow.js
@@ -1,7 +1,6 @@
 'use strict'
 
 const debug = require('debug')('lint-staged:git')
-const normalize = require('normalize-path')
 const path = require('path')
 
 const execGit = require('./execGit')
@@ -69,28 +68,6 @@ class GitWorkflow {
       debug('Done backing up merge state!')
     }
 
-    // Git stash ignores new, untracked files, so back them up separately
-    // Use `git ls-files` to list untracked files:
-    // `--others includes` all untracked files, including ignored files
-    // `--exclude-standard` excludes ignored files, the .git/ dir and so on...
-    let untrackedFiles = await this.execGit(['ls-files', '--others', '--exclude-standard'])
-    if (untrackedFiles) {
-      debug('Detected untracked files:')
-      debug(untrackedFiles)
-      debug('Backing up untracked files...')
-      // Resolve untrackedFiles output into filenames
-      untrackedFiles = untrackedFiles
-        .split('\n')
-        .map(file => normalize(path.resolve(this.cwd, file)))
-      this.untrackedFiles = new Map()
-      await Promise.all(
-        untrackedFiles.map(file =>
-          readBufferFromFile(file).then(buffer => this.untrackedFiles.set(file, buffer))
-        )
-      )
-      debug('Done backing up untracked files!')
-    }
-
     // Get stash of entire original state, including unstaged changes
     await this.execGit(['stash', 'save', '--quiet', '--include-untracked', STASH])
     // Apply index from previous stash back to enable running tasks against
@@ -155,22 +132,16 @@ class GitWorkflow {
       debug('Done restoring unstaged changes!')
     }
 
-    if (this.untrackedFiles) {
-      debug('Restoring untracked files...')
-      try {
-        // Iterate over Map and await for all to complete
-        const writePromises = []
-        this.untrackedFiles.forEach((buffer, file) => {
-          writePromises.push(writeBufferToFile(file, buffer))
-        })
-        await Promise.all(writePromises)
-      } catch (error) {
-        debug('Error while restoring untracked changes:')
-        debug(error)
-        throw new Error('Untracked changes could not be restored due to an error!')
-      }
-      debug('Done restoring untracked files!')
-    }
+    // Restore untracked files by reading from the third commit associated with the backup stash
+    // Git will return with error code if the commit doesn't exist
+    // See https://stackoverflow.com/a/52357762
+    try {
+      const backupStash = await this.getBackupStash()
+      const output = await this.execGit(['show', '--format=%b', `${backupStash}^3`])
+      const untrackedDiff = output.replace(/^\n*/, '') // remove empty lines from start of output
+      if (!untrackedDiff) return
+      await this.execGit([...gitApplyArgs], { input: `${untrackedDiff}\n` })
+    } catch (err) {} // eslint-disable-line no-empty
   }
 
   /**