MERGE_HEAD is lost when repository is using submodules feature

[armata007]

Description

Some naming I use in issue below:

1. path-to-repo is jjust some path
2. repo is actual repository name (main repository)
3. submodule - name of repository which is submodule of repo

After updating to v10.0.0 MERGE_* files are lost when merging branch with conflicts in case of repository with submodules. I think it is connected to #756 .

Normally when using git repository /Users/path-to-repo/repo/.git/ is a folder and MERGE_* files are created inside it. But when using submodules feature /Users/pathpath-to-repo/repo/submodule/.git is a file containing path to actual .git directory, for example
gitdir: ../.git/modules/submodule. So /Users/path-to-repo/repo/submodule/.git is a file, containing path to /Users/path-to-repo/repo/.git/modules/submodule/ which is a proper directory where all MERGE_* files are really kept.

From the debug logs I can see that lint-staged is reading MERGE_* files from wrong path:
lint-staged:file Reading buffer from file '/Users/path-to-repo/repo/submodule/.git/MERGE_HEAD'
but it should read it from /Users/path-to-repo/repo/.git/modules/submodule/MERGE_HEAD

Steps to reproduce

1. Have repository which is using submodules
2. In one of the modules merge branch with conflicts
3. after lint-staged is run MERGE message and MERGE_HEAD are lost
4. if you fill in commit message you should also get
   fatal: could not open '/Users/path-to-repo/repo/.git/modules/submodule/MERGE_HEAD' for reading: No such file or directory

Debug Logs

expand to view

lint-staged:run Running all linter scripts +0ms
  lint-staged:git Running git command [ 'rev-parse', '--show-toplevel' ] +0ms
  lint-staged:run Resolved git directory to be `/Users/path-to-repo/repo/submodule` +21ms
  lint-staged:git Running git command [ 'diff', '--staged', '--diff-filter=ACMR', '--name-only' ] +20ms
  lint-staged:run Loaded list of staged files in git:
  lint-staged:run [ 
  ... files
  ] +21ms
  lint-staged:chunkFiles Resolved an argument string length of 6920 characters from 64 files +0ms
  lint-staged:chunkFiles Creating 1 chunks for maxArgLength of 131072 +0ms
  lint-staged:gen-tasks Generating linter tasks +0ms
  lint-staged:gen-tasks Generated task:
  lint-staged:gen-tasks { pattern: '*.{less,css}',
  lint-staged:gen-tasks   commands: [ 'prettier --write' ],
  lint-staged:gen-tasks   fileList: [] } +9ms
  lint-staged:gen-tasks Generated task:
  lint-staged:gen-tasks { pattern: '*.{js,jsx,ts,tsx}',
  lint-staged:gen-tasks   commands:
  lint-staged:gen-tasks    [ 'prettier --write',
  lint-staged:gen-tasks      'eslint -c .eslintrc.fix.js --ext .js --ext .jsx --fix --ext .ts --ext .tsx --fix',
  lint-staged:gen-tasks      'eslint -c .eslintrc.js --ext .js --ext .jsx --fix --ext .ts --ext .tsx' ],
  lint-staged:gen-tasks   fileList:
  lint-staged:gen-tasks    [ ...files ] } +1ms
  lint-staged:make-cmd-tasks Creating listr tasks for commands [ 'prettier --write' ] +0ms
  lint-staged:task cmd: prettier --write  +0ms
  lint-staged:task execaOptions: { preferLocal: true, reject: false, shell: false } +0ms
  lint-staged:make-cmd-tasks Creating listr tasks for commands [ 'prettier --write', 'eslint -c .eslintrc.fix.js --ext .js --ext .jsx --fix --ext .ts --ext .tsx --fix', 'eslint -c .eslintrc.js --ext .js --ext .jsx --fix --ext .ts --ext .tsx' ] +4ms
  lint-staged:task cmd: prettier --write ...files +0ms
  lint-staged:task execaOptions: { preferLocal: true, reject: false, shell: false } +0ms
  lint-staged:task cmd: eslint -c .eslintrc.fix.js --ext .js --ext .jsx --fix --ext .ts --ext .tsx --fix ...files +1ms
  lint-staged:task execaOptions: { preferLocal: true, reject: false, shell: false } +43ms
  lint-staged:task cmd: eslint -c .eslintrc.js --ext .js --ext .jsx --fix --ext .ts --ext .tsx ...files +1ms
  lint-staged:task execaOptions: { preferLocal: true, reject: false, shell: false } +0ms
Preparing... [started]
  lint-staged:git Backing up original state... +0ms
  lint-staged:git Backing up merge state... +0ms
  lint-staged:file Reading buffer from file `/Users/path-to-repo/repo/submodule/.git/MERGE_HEAD` +0ms
  lint-staged:file Reading buffer from file `/Users/path-to-repo/repo/submodule/.git/MERGE_MODE` +0ms
  lint-staged:file Reading buffer from file `/Users/path-to-repo/repo/submodule/.git/MERGE_MSG` +0ms
  lint-staged:file Done reading buffer from file `/Users/path-to-repo/repo/submodule/.git/MERGE_HEAD`! +5ms
  lint-staged:file Done reading buffer from file `/Users/path-to-repo/repo/submodule/.git/MERGE_MODE`! +0ms
  lint-staged:file Done reading buffer from file `/Users/path-to-repo/repo/submodule/.git/MERGE_MSG`! +36ms
  lint-staged:git Done backing up merge state! +41ms
  lint-staged:git Running git command [ 'stash',
  'save',
  '--quiet',
  '--include-untracked',
  '--keep-index',
  'lint-staged automatic backup' ] +150ms
  lint-staged:git Restoring merge state... +1s
  lint-staged:git Done restoring merge state! +0ms
  lint-staged:git Running git command [ 'ls-files', '--others', '--exclude-standard' ] +1s
  lint-staged:git Running git command [ 'stash', 'list' ] +107ms
  lint-staged:git Running git command [ 'diff',
  '--binary',
  '--unified=0',
  '--no-color',
  '--no-ext-diff',
  '--patch',
  'stash@{0}',
  '-R' ] +290ms
  lint-staged:git Done backing up original state! +468m

Environment

• OS: macOS Catalina
• Node.js: v10.17.0
• lint-staged: v10.0.0

[iiroj]

Thanks for the good issue description, @armata007! I'll take a look. Should be straightforward as long as we can detect that the current dir is a submodule.

[iiroj]

@armata007 Do you think you could manually test that my fix works? You can clone this GitHub repo locally, then check out the branch submodule-merge-conflict and then swap the lint-staged bin to point to the checked out repo like <repo_location>/bin/lint-staged.

So something like:

cd /path/to/github-repositories
git clone git@github.com:okonet/lint-staged.git
cd lint-staged
git checkout submodule-merge-conflict
yarn

After this edit your husky/whatever script to run /path/to/github-repositories/lint-staged/bin/lint-staged.

[okonet]

🎉 This issue has been resolved in version 10.0.1 🎉

The release is available on:

• npm package (@latest dist-tag)
• GitHub release

Your semantic-release bot 📦🚀