.github

PR base check (reusable workflow)

.github/workflows/pr-base-check.yml fails a pull request whose base branch is a dead end, i.e. a feature branch that already merged to dev (or has no route to it). A merged PR only proves it landed in its base; if that base already merged to dev, the work never reaches dev (TD-7928 morph, api#2890 / tiled-mono#608).

Add it to a repo with a caller workflow:

name: PR base check
on:
  pull_request:
    types: [opened, edited, reopened, synchronize, labeled, unlabeled]
permissions:
  contents: read
  pull-requests: read
jobs:
  base-check:
    uses: TiledCo/.github/.github/workflows/pr-base-check.yml@master

• Mainline bases always pass: dev, master, main, pre-production, release/*, hotfix/*, env<N> (override with the allowed-bases input).
• A non-mainline base passes only while it still has an open PR into a mainline branch (a stacked PR).
• Deliberate exceptions: add the stacked-pr label to the PR.
• It only blocks merging once PR base check / base-check is a required status check on the target branch.