Check for previous CI runs with the same tree

Author: lkrms

.ci-pathspec

@@ -0,0 +1,16 @@
+.github/workflows/**
+bin/**
+scripts/**
+src/**
+stubs/**
+tests/**
+tools/**
+.ci-pathspec
+.gitattributes
+.php-cs-fixer.dist.php
+.prettyphp
+codecov.yml
+composer.json
+composer.lock
+phpstan*
+phpunit.xml.dist

.gitattributes

@@ -1,3 +1,4 @@
+/.ci-pathspec export-ignore
 /.git-blame-ignore-revs export-ignore
 /.gitattributes export-ignore
 /.github export-ignore

.github/workflows/check-ci-runs.yml

@@ -0,0 +1,47 @@
+name: Check CI runs
+
+on:
+  workflow_call:
+    inputs:
+      ci_workflow:
+        description: CI workflow name
+        type: string
+        required: true
+    outputs:
+      ci_required:
+        description: "Whether a CI workflow run is required for the current tree (0 = no, 1 = yes)"
+        value: ${{ jobs.check-ci-runs.outputs.ci_required }}
+
+jobs:
+  check-ci-runs:
+    name: Check CI workflow runs
+    runs-on: ubuntu-latest
+    outputs:
+      ci_required: ${{ steps.get-ci-required.outputs.ci_required }}
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+
+      - name: Check for a successful run with the same tree
+        id: get-ci-required
+        shell: bash
+        run: |
+          ci_required=1
+          mapfile -t pathspec < <([[ -f .ci-pathspec ]] && sed -E $'/^[ \t]*(#|$)/d' .ci-pathspec)
+          while read -r ref; do
+              git diff-tree --quiet "$ref" HEAD -- ${pathspec+"${pathspec[@]}"} || continue
+              printf '%s workflow already succeeded with the same tree: %s\n' "$ci_workflow" "$ref"
+              ci_required=0
+              break
+          done < <(
+              git rev-list --no-merges HEAD |
+                  grep -Fxf <(gh run list --workflow "$ci_workflow" --status success --json headSha --jq '.[].headSha')
+          )
+          ((!ci_required)) || printf 'No successful %s workflow runs found with the same tree\n' "$ci_workflow"
+          printf 'ci_required=%d\n' "$ci_required" | tee -a "$GITHUB_OUTPUT"
+        env:
+          ci_workflow: ${{ inputs.ci_workflow }}
+          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}

.github/workflows/ci.yml

@@ -7,15 +7,25 @@ on:
 
   pull_request:
 
-  workflow_dispatch:
+  workflow_call:
 
 concurrency:
   group: ${{ github.workflow }}-${{ github.head_ref || github.ref }}
   cancel-in-progress: true
 
 jobs:
+  check-ci-runs:
+    name: Check previous runs
+    if: ${{ github.event_name != 'workflow_call' }}
+    uses: ./.github/workflows/check-ci-runs.yml
+    with:
+      ci_workflow: CI
+
   check:
     name: Check generated files and formatting
+    needs:
+      - check-ci-runs
+    if: ${{ (github.event_name == 'workflow_call' || needs.check-ci-runs.outputs.ci_required == 1) && !cancelled() && !failure() }}
     runs-on: ubuntu-latest
 
     steps:
@@ -54,8 +64,11 @@ jobs:
 
   phpstan:
     name: PHPStan
+    needs:
+      - check
+      - check-ci-runs
+    if: ${{ (github.event_name == 'workflow_call' || needs.check-ci-runs.outputs.ci_required == 1) && !cancelled() && !failure() }}
     runs-on: ubuntu-latest
-    needs: check
 
     strategy:
       fail-fast: false
@@ -101,7 +114,10 @@ jobs:
 
   unit-tests:
     name: PHPUnit tests
-    needs: check
+    needs:
+      - check
+      - check-ci-runs
+    if: ${{ (github.event_name == 'workflow_call' || needs.check-ci-runs.outputs.ci_required == 1) && !cancelled() && !failure() }}
 
     strategy:
       fail-fast: false