Checkout fails on pull request closed event

[jwnx]

Hello everyone,

So, I have a .github/workflow/docker.yml like this:

name: Maybe update Docker image

on:
  pull_request:
    types: [closed]

jobs:
  maybe_update:
    runs-on: ubuntu-latest

    if: github.event.pull_request.merged == true

    steps:
    - name: Checkout
      uses: actions/checkout@v2

Which is pretty basic. The goal is to run this on master after a pull request is merged. It does find the lastest commit on master (be3c9f9), as seen here:

/usr/bin/git config --local gc.auto 0
/usr/bin/git config --local --name-only --get-regexp http\.https\:\/\/github\.com\/\.extraheader
/usr/bin/git config --local http.https://github.com/.extraheader AUTHORIZATION: basic ***
/usr/bin/git -c protocol.version=2 fetch --no-tags --prune --progress --no-recurse-submodules --depth=1 origin be3c9f9d09e54097321f92f452923a91435b63ac

But when it comes to checking out, it cant:

From https://github.com/...
 * branch            be3c9f9d09e54097321f92f452923a91435b63ac -> FETCH_HEAD
/usr/bin/git branch --list --remote origin/master
/usr/bin/git tag --list master
Removed matchers: 'checkout-git'
##[error]A branch or tag with the name 'master' could not be found
##[error]Node run failed with exit code 1

We also tried tying it explicitly to master, like this:

name: Maybe update Docker image

on:
  pull_request:
    branches: [master]
    types: [closed]    

But the same problem occurs. Any ideas? (:

cheers

[jwnx]

I was able to solve this by using:

- uses: actions/checkout@v2
  with:
    ref: master

Now, I thought ref: master was the default behaviour. The fact that I had to explicitly use ref: master makes me think this is a bug. I will wait til someone confirms in order to close this.

[ericsciple]

Updated title

[GMNGeoffrey]

Master is only the default if it's checking out another repository, I think. Otherwise it defaults to whatever triggered the event.

From the README:

# The branch, tag or SHA to checkout. When checking out the repository that
# triggered a workflow, this defaults to the reference or SHA for that event.
# Otherwise, defaults to `master`.

But the readme also gives this as the recipe for checking out a closed pull request, which seems wrong:

on:
  pull_request:
    branches: [master]
    types: [opened, synchronize, closed]
jobs:
  build:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v2

@jwnx, I think your workaround is going to run into race conditions if there's another push to master in the meantime. We just run things on push to master, which I think should achieve the same result? Unless you don't want to run if someone pushes straight to master and only for merged pull requests for some reason?

on:
  push:
    branches: [master]

I am experiencing the same error in a slightly different context though (apologies if this should be in a different issue). Our automation force pushes to a PR branch before merging and this triggers another run of the workflow, which fails with that same error message because the PR is already closed (e.g. https://github.com/google/iree/runs/395655503). Could the handling for closed pull requests be better overall?

Is there a way to get the action to always check out a valid commit, or abort if the PR has already been closed? (We run the relevant things on pushes to master anyway).

[haya14busa]

+1. I think a correct workaround is to use github.ref.
I hope it will be solved by default though.

on:
  pull_request:
    types: [closed]
jobs:
  release:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v2
        with:
          ref: ${{ github.ref }}

[GMNGeoffrey]

Thanks for fixing. The spurious status failures have gone away.