Only a single (grafted) commit left in branch after checkout with extension?

• Extension version: 0.5.0
• VSCode Version: 1.32.1
• OS: Windows 10 64-bit

Steps to Reproduce:

Unclear. I tried to reproduce the problem with a simplified setup, but to no avail. Here is a list of things I remember:

• Had accidentally staged all changed/untracked files
• Unstaged them one by one by clicking the - button on them in source code management sidebar in quick succession (in parallel? it tooks quite a while until it finished in the background)
• Installed GitHub extension
• The working copy had branch devel checked out, potentially not up-to-date with remote
• I wanted to edit something a feature branch call documentation/graph-traversal-build-fix
• There was already a local branch with that name, but it was behind the remote branch (same name)
  • I had merged origin/devel into documentation/graph-traversal-build-fix on a different machine
  • My local branch was behind but that merge commit
• Via the GitHub extension, I located the corresponding PR for that branch and clicked the Checkout button
• When I checked git log the next time in a command prompt, it only gave me this:

  >git log
  commit b7aa332a80c16be8c74c51fb7c2f7cdb8e4e8ff2 (grafted, HEAD -> documentation/graph-traversal-build-fix, origin/documentation/graph-traversal-build-fix)
  Author: Simran ...
  Date:   Fri Mar 8 15:18:44 2019 +0100
  
      Merge remote-tracking branch 'origin/devel' into documentation/graph-traversal-build-fix
  
  

  So the entire history of that branch looks like a single commit and is the merge commit (the one I was behind before the Checkout via the GitHub extension)
• Shortly after, I noted that it said grafted. In a shallow clone of a repository, it would be expected that you see a truncated history. However, my repo wasn’t a shallow clone but a normal working copy with the entire history.
• The PR on GitHub based on the documentation/graph-traversal-build-fix branch looked alright, so I deleted my local branch and checked out the remote branch - but the history remained a single commit
• Then I tried to reset --hard, but this didn’t change anything either

I cloned the entire repo to a new folder, and there the branch is fine, i.e. the entire history is listed as expected. Does this mean some cache in the original working copy got corrupted?

What does the GitHub extension do exactly if you check out pull requests? Is there any chance for breaking the working copy as described? Is it caused by how the extension uses Git, or does this sound like a bug in Git itself?

If you want to analyze the (possibly) corrupted working copy, download it here: arangodb-grafted.7z (1.1 GB)

[sunsations]

@Simran-B I had the same problem. Solution was to delete the .git/shallow file.

[deepskyblue86]

Same here. git fetch --unshallow did the job.