Get all files changed by PR after squash-merging

[dionhaefner]

I am using a workflow that triggers after a PR is merged into main. My goal is to use tj-actions/changed-files to find which files were modified by the PR:

on:
  pull_request:
    types:
      # closed could be merged or closed without merging
      # jobs must check if PR was merged
      - closed
    branches:
      - main

jobs:
  get-affected-files:
    runs-on: ubuntu-22.04
    if: github.event.pull_request.merged == true

    steps:
      - uses: actions/checkout@v3
        with:
          fetch-depth: 0

      - name: Get changed files
        id: changed-files
        uses: tj-actions/changed-files@v36

I noticed that this includes additional files (that are not part of the PR / merge commit) if the PR wasn't up-to-date with main. I assume that we need to pass a different base SHA to compare with, but I can't seem to figure it out. Happy for any pointers.

Our repo has mandatory squash-merging in case it's relevant.

[jackton1]

Hi @dionhaefner, You'll have to upgrade to the latest major version.

[dionhaefner]

Thanks. Is this something that was fixed recently? I didn't see anything in the changelog.

[shinebayar-g]

I have a same requirement and going to implement something similar. I think you need to double check if the commit you're comparing is the correct pull request commit. For example before uses: actions/checkout@v3 happens, there could be another PR merged. So you can't assume checkout will always get the correct PR merge. I'd suggest double check the commit message and see if it includes the PR link. Squash merged commit messages include their PR number in the commit message by default (unless manually removed).

[dionhaefner]

FWIW, I added

base_sha: ${{ github.event.pull_request.base.sha }}

to the config and haven't noticed any problems since.