ci: Fix per commit CI

The pull request event does not have write access to the repo, so it
cannot dispatch jobs.

Author: NickeZ

.ci/matrix-from-commit-log

@@ -0,0 +1,13 @@
+#!/usr/bin/python
+
+import subprocess
+import sys
+import json
+
+range = sys.argv[1]
+
+commits = subprocess.run(f'git log --format="%H" {range}', shell=True, text=True, capture_output=True)
+commits = commits.stdout.strip().split()
+
+if len(commits) > 0:
+  print(json.dumps({'commit': commits}))

.github/workflows/commit-ci.yml

@@ -1,31 +1,67 @@
 # See reference docs at
 # https://help.github.com/en/actions/reference/workflow-syntax-for-github-actions
+
 name: Pull request CI
 on: pull_request
 
 jobs:
-  pr-ci:
+  pr-head-ci:
+    runs-on: ubuntu-22.04
+    steps:
+      - name: Clone the repo
+        uses: actions/checkout@v4
+        with:
+          submodules: recursive
+
+      - name: Pull container image
+        run: ./.ci/run-container-ci pull
+
+      - name: Run CI in container
+        run: ./.ci/run-container-ci ${{github.workspace}} ${{ github.base_ref }}
+
+  # Generate a list of commits to run CI on
+  generate-matrix:
+    runs-on: ubuntu-22.04
+    outputs:
+      matrix: ${{ steps.set-matrix.outputs.matrix }}
+    steps:
+      - name: Clone the repo
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+
+      # HEAD~ because  we want to skip the last commit (which is built in job above)
+      - name: Create jobs for commits in PR history
+        id: set-matrix
+        run: |
+          echo matrix=$(.ci/matrix-from-commit-log origin/${{github.base_ref}}..${{ github.event.pull_request.head.sha}}~) >> $GITHUB_OUTPUT
+
+  # Run this job for every commit in the PR except HEAD.
+  pr-commit-ci:
     runs-on: ubuntu-22.04
+    needs: [ generate-matrix ]
+    strategy:
+      matrix: ${{ fromJSON(needs.generate-matrix.outputs.matrix) }}
+    if: needs.generate-matrix.outputs.matrix != ''
     steps:
       - name: Clone the repo
         uses: actions/checkout@v4
         with:
           submodules: recursive
           fetch-depth: 0
+          ref: ${{ github.event.pull_request.base.sha }}
 
-      # HEAD^2~ because PR branch is second parent and we want to skip the last commit
-      - name: Dispatch jobs for commits in PR history
+      - name: Create merge commit
+        env:
+          GIT_AUTHOR_NAME: Bot
+          GIT_AUTHOR_EMAIL: bot@bitbox.swiss
+          GIT_COMMITTER_NAME: Bot
+          GIT_COMMITTER_EMAIL: bot@bitbox.swiss
         run: |
-          for commit in $(git log --format="%H" origin/${{github.base_ref}}..HEAD^2~); do
-            echo ::notice::Dispatching job for $commit
-            curl -L -s \
-              -X POST \
-              -H "Accept: application/vnd.github+json" \
-              -H "Authorization: Bearer ${{ secrets.GITHUB_TOKEN }}" \
-              -H "X-GitHub-Api-Version: 2022-11-28" \
-              ${{ github.api_url }}/repos/${{ github.repository }}/actions/workflows/commit-ci.yml/dispatches \
-              -d "{\"ref\":\"${{ github.event.pull_request.head.ref }}\",\"inputs\":{\"sha\":\"$commit\",\"base_ref\":\"${{ github.base_ref}}\"}}"
-          done
+          git fetch origin ${{ matrix.commit }}
+          git merge --no-ff --no-edit ${{ matrix.commit }}
+          echo "merge commit parents:"
+          git log -1 --format="Head %H, Parents %P"
 
       - name: Pull container image
         run: ./.ci/run-container-ci pull