reset hard on git push

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The issue is a difference in how Git commands behave in the environment created for hook scripts versus your normal environment.

First, hook scripts run with their current working directory set to the Git directory itself (i.e. the .git/ directory of a non-bare repository). Second, hook scripts run with the GIT_DIR environment variable set and pointing to the Git repository (again, the .git/ directory of a non-bare repository).

Normally, if you try to run git reset --hard from the .git/ directory, it will die with the following message:

fatal: This operation must be run in a work tree

But when GIT_DIR is set, Git commands assume that the current directory is the working tree. Since the current directory when the hook runs is the .git/ directory, your git reset --hard is actually “checking out” your working tree files directly into .git/ instead of its parent directory (i.e. you now have a copy of your versioned content in your .git/ directory).

Hopefully none of versioned content in your repository has pathnames that coincide with pathnames that Git uses in Git repositories themselves. If they do coincide, then your git reset --hard will have overwritten some bit of the internal structure of your repository and you will probably want to re-clone it from some other repository. If you are confident that none of the versioned content conflicts with Git’s internal pathnames, then you may be able to clean it up with this:

# make a backup of your repository first!
(cd .git && GIT_DIR=$PWD git ls-files -cz | xargs -0 rm)

This will only remove currently tracked files (it will leave behind files that have since been removed, but were once tracked in tip commits pushed while the broken hook was active).

One solution is to change the current working directory to the normal working tree and unset GIT_DIR and GIT_WORK_TREE before calling Git commands.

⋮
test "${PWD%/.git}" != "$PWD" && cd .. 
unset GIT_DIR GIT_WORK_TREE
# you can now safely use Git commands
⋮

Another solution is to explicitly reset GIT_DIR, set GIT_WORK_TREE and chdir there. The Git FAQ “Why won’t I see changes in the remote repo after “git push”?” recommends a post-update script that does just this. The linked script is also much safer since it makes a stash if the index or working tree is dirty before doing the hard reset.

More Related Contents:

  1. Putting Git hooks into a repository
  2. How to configure Git post commit hook
  3. In plain English, what does “git reset” do?
  4. Writing a git post-receive hook to deal with a specific branch
  5. Git Post-Receive Hook for Website Staging
  6. Applying a git post-commit hook to all current and future repositories
  7. Git pre-commit hook : changed/added files
  8. In Git, how can I write the current commit hash to a file in the same commit
  9. Git pre-push hooks
  10. How do I prompt the user from within a commit-msg hook?
  11. Is there any git hook for pull?
  12. How to git reset –hard a subdirectory
  13. git-clone and post-checkout hook
  14. Can you change a file content during git commit?
  15. Get commit message in Git hook
  16. unstaged files gone after git reset –hard
  17. Git push requires username and password
  18. How can I automatically push after committing in Git?
  19. Git SSH authentication
  20. What is the best practice for dealing with passwords in git repositories?
  21. Setting up and using Meld as your git difftool and mergetool
  22. How do you use “git –bare init” repository?
  23. Who is “us” and who is “them” according to Git?
  24. heroku: src refspec master does not match any
  25. Git: can I suppress listing of ‘modified content’/dirty submodule entries in status, diff, etc?
  26. Pass an argument to a Git alias command
  27. Git rebase fails, ‘Your local changes to the following files would be overwritten by merge’. No local changes?
  28. Can I split an already split hunk with git?
  29. View differences of branches with meld?
  30. Setting up sublimetext 3 as git commit text editor

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