CI: check that the changelog is populated on each pull request

.github/workflows/check_push.yml

@@ -1,6 +1,7 @@
 name: Check branch conformity
 on:
-  push:
+  pull_request:
+      types: [opened, synchronize, reopened]
 
 jobs:
   prevent-fixup-commits:
@@ -17,3 +18,16 @@ jobs:
             git fetch origin
             git status
             git log --pretty=format:%s origin/main..HEAD | grep -ie '^fixup\|^wip' && exit 1 || true
+
+  check-changelog:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+      - name: ensure CHANGELOG.md is populated
+        run: |
+          CHANGELOG_MODIFIED=$(git diff --name-only ${{ github.event.pull_request.base.sha }} | grep -c "CHANGELOG.md")
+          if [ $CHANGELOG_MODIFIED -eq 0 ]; then
+            echo "::error::No CHANGELOG modifications found in this pull request. Please update the CHANGELOG."
+            exit 1
+          fi

CHANGELOG.md

@@ -7,6 +7,11 @@ since 0.4.1, and this project adheres to [Semantic Versioning](https://semver.or
 
 ## [Unreleased](https://github.com/freedomofpress/dangerzone/compare/v0.8.0...HEAD)
 
+### Development changes
+
+- CI: Check that the changelog is populated on each pull request ([#995](https://github.com/freedomofpress/dangerzone/pull/995))
+
+
 ## [0.8.0](https://github.com/freedomofpress/dangerzone/compare/v0.8.0...0.7.1)
 
 ### Added