checkout: Error while checking out: "fatal: reference is not a tree"

@soluchok Apologies, we’re still working on a fix for this! I was on vacation, so I’ll hopefully get one in soon and update this ticket accordingly.

Looks like the wrong REF only happened when we try to re-run a failed workflow.

@iheanyi thread: https://twitter.com/Runspired/status/1191746539372212224

Roughly I believe the root of the issue is a race condition between when @actions/checkout triggers the checkout and when the merge commit has been created in the repo.

If the checkout occurs before the commit is created, then checkout results in creating the merge commit itself which results in a different SHA than the SHA that is used for $GITHUB_SHA

For some reason this condition is far more common when it is a new commit to an open PR.

I suspect roughly the flow behind the scenes is (in order of A -> G)

success

- A workflow triggered
  - B create merge commit
  - C populate GITHUB_SHA
  - D push merge commit and branch to repository
     - F repository receives new merge commit
  - E begin workflow
     - G checkout PR branch on repository

failure

- A workflow triggered
  - B create merge commit
  - C populate GITHUB_SHA
  - D push merge commit and branch to repository
     - G repository receives new merge commit
  - E begin workflow
     - F checkout PR branch on repository

Looks like the wrong REF only happened when we try to re-run a failed workflow.

This seems to be it in my case - made a dummy commit and now the workflow is running fine. Using Amplify though.

The last comment is from half a year ago so I’d like to update and say this issue is indeed still happening. I can’t see why it is closed, because the “145 hidden items - Load more items” button doesn’t work, but if it was fix, looks like the fix is incomplete or there are multiple ways to trigger this issue.

Ran into this issue as I’ve got the same error in my github action.

For me it was resolved today by running git pull --all in the action shell script before doing anything else with the git repository.

Reasoning: seems like github creates a shallow-depth git repo by default as the git branch -a command only listed the master branch (plus the remotes/origin/master one) while the repo had at least one other branch. Only after running git pull --all as part of the action code did that other branch show up and did my other git commands start to behave as expected.

HTH.

Action YML:

name: learn-github-actions
on: [push]
jobs:
  fix-illegal-names:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v2
      - run: bash ./fix-bad-names.sh

shell script in repo root:

ls -lr
git config user.email github-action@hobbelt.com 
git config user.name Github-Action
git pull --all
# show the branches known to git: allows visual check in 'actions' web page
git branch -a
# create local branch when running the action
git checkout -b clean-marker --track remotes/origin/clean-marker
# `ls -lr` for visual feedback and check to see if checkout command succeeded indeed
ls -lr

# do some work on that branch (anything) -- instead of working on HEAD
echo "replace : colons in filenames"
find . -name '*:*' -print | sed -e 's/\(.*\)/mv "\1" @@ "\1"/' -e 's/@@ \(.*\):\(.*\)/\1_\2/g' > rn_us.sh
chmod a+x rn_us.sh
cat rn_us.sh
./rn_us.sh

ls -lr
find . -name '*_*' -print | grep -v '\.git'
find . -name '*_*' -print | grep -v '\.git' | xargs -n 1 -d '\n' git add 

# push back the edits into my own github repo
git commit -a -m "fixed file names for Windows compatibility"
git push --all

NOTE: I suspect the shallow repo copy as any git checkout would fail, even when specifying commit hashes instead of branch names, and that also when the commit was a close predecessor of the HEAD commit – only spot checked this with a distance of about 5, had an idea and moved on that: that’s where I came up with the git pull --all which did fix the problem for me at least.

Our build is still affected by this issue, and v2 version doesn’t seem to do a difference. Similar to what @localheinz commented, we also use fetch-depth: 0 configuration which could be the common denominator with our issues.

@wl2776 this repo is for GitHub Actions. If you are seeing bugs in various Jenkins plugins please report those there.

@sebdau sorry but that is the Azure DevOps product. This repo is for GitHub Actions 😦

I’m seeing this error, too. Our build is not yet using YAML but classic UI-style release pipe. According to the logs, this is still using V1 git task. Is there a way to change the task version?

https://msazure.visualstudio.com/One/_build/results?buildId=28043911&view=logs&j=92a4755a-6173-591e-5c07-8dbe1165e937&t=ead66276-ec45-5be0-fa6c-361c94a3aa0c&l=5

Thx, Seb