Actions: error when setting automerge on a PR without contents write permission #4086
Description
Describe the bug
When using an action to enable auto-merge, you get a cryptic error message if you're missing the contents: write permission.
gh version 1.13.1 (2021-07-20)
Steps to reproduce the behavior
Attempting to enable auto-merging as described in the dependabot docs, we implemented an action by copying that example:
name: Dependabot auto-merge
on: pull_request_target
permissions:
pull-requests: write
contents: write # <==== missed this permission
jobs:
dependabot:
runs-on: ubuntu-latest
if: ${{ github.actor == 'dependabot[bot]' }}
steps:
- name: Dependabot metadata
id: metadata
uses: dependabot/fetch-metadata@v1.1.0
with:
github-token: "${{ secrets.GITHUB_TOKEN }}"
- name: Enable auto-merge for Dependabot PRs
if: ${{contains(steps.metadata.outputs.dependency-names, 'my-dependency') && steps.metadata.outputs.update-type == 'version-update:semver-patch'}}
run: gh pr merge --auto --merge "$PR_URL"
env:
PR_URL: ${{github.event.pull_request.html_url}}
GITHUB_TOKEN: ${{secrets.GITHUB_TOKEN}}
When this action ran, it gave the following output:
gh pr merge --auto --merge "$PR_URL"
json: cannot unmarshal number into Go struct field GraphQLError.Errors.Path of type string
Expected vs actual behavior
Eventually I worked out it was because the action wasn't given the content: write permission (though I couldn't find any documentation indicating what permissions were needed for which commands).
A more helpful error message would have made this much easier.
The closest I could find to this problem by googling was #3346, which identified a bug "Our GraphQL error-handling mechanism doesn't handle the case when the path property of an error is an array that contains a mix of strings and numbers."