Change changelog update from merge to PR event

.github/workflows/write-changelog.yml

@@ -1,56 +1,34 @@
-name: Update Changelog on merge to main (append)
+name: Update Changelog on PR (write to PR branch)
 
 on:
-  push:
-    branches:
-      - main
-
-permissions:
-  contents: write
-  pull-requests: read
+  pull_request:
+    types: [opened, edited, synchronize, reopened]
 
 jobs:
   update-changelog:
+    if: >
+      github.event.pull_request.merged != true &&
+      github.event.pull_request.base.ref == 'main'
     runs-on: ubuntu-latest
+    permissions:
+      contents: write
+      pull-requests: read
     steps:
-      - name: Checkout main
+      - name: Checkout PR branch
         uses: actions/checkout@v4
         with:
-          ref: main
+          ref: ${{ github.event.pull_request.head.ref }}
           fetch-depth: 0
 
-      - name: Determine source PR (if any)
-        id: prinfo
-        run: |
-          # Try to find the pull request that was merged into this push (if the push is a merge commit)
-          # Look for PRs whose merge_commit_sha matches HEAD
-          head_sha=$(git rev-parse HEAD)
-          pr_number=$(gh api repos/${{ github.repository }}/commits/${head_sha}/pulls --jq '.[0].number' 2>/dev/null || true)
-          if [ -z "$pr_number" ]; then
-            # fallback: try to find PR by searching merged PRs with HEAD in merge_commit_sha via REST
-            pr_number=$(gh api repos/${{ github.repository }}/pulls --jq '.[] | select(.merge_commit_sha == env.HEAD_SHA) | .number' --paginate 2>/dev/null || true)
-          fi
-          echo "head_sha=$head_sha" >> "$GITHUB_OUTPUT"
-          echo "pr_number=${pr_number:-}" >> "$GITHUB_OUTPUT"
-
-      - name: Gather PR info (if found) or use last commit message
+      - name: Gather PR info
         id: info
         run: |
-          pr_number="${{ steps.prinfo.outputs.pr_number }}"
-          if [ -n "$pr_number" ]; then
-            pr_json=$(gh api repos/${{ github.repository }}/pulls/$pr_number)
-            pr_title=$(printf '%s' "$pr_json" | jq -r .title)
-            pr_user_login=$(printf '%s' "$pr_json" | jq -r .user.login)
-            pr_html_url=$(printf '%s' "$pr_json" | jq -r .html_url)
-            created_at=$(printf '%s' "$pr_json" | jq -r .created_at)
-          else
-            # No PR found: use last commit info
-            pr_title=$(git log -1 --pretty=%s)
-            pr_user_login=$(git log -1 --pretty=%an)
-            pr_html_url=""
-            created_at=$(git log -1 --pretty=%cI)
-          fi
-          echo "pr_number=${pr_number:-}" >> "$GITHUB_OUTPUT"
+          pr_number=$(jq -r .pull_request.number "$GITHUB_EVENT_PATH")
+          pr_title=$(jq -r .pull_request.title "$GITHUB_EVENT_PATH")
+          pr_user_login=$(jq -r .pull_request.user.login "$GITHUB_EVENT_PATH")
+          pr_html_url=$(jq -r .pull_request.html_url "$GITHUB_EVENT_PATH")
+          created_at=$(jq -r .pull_request.created_at "$GITHUB_EVENT_PATH")
+          echo "pr_number=$pr_number" >> "$GITHUB_OUTPUT"
           echo "pr_title=$pr_title" >> "$GITHUB_OUTPUT"
           echo "pr_user_login=$pr_user_login" >> "$GITHUB_OUTPUT"
           echo "pr_html_url=$pr_html_url" >> "$GITHUB_OUTPUT"
@@ -71,11 +49,7 @@ jobs:
           pr_number="${{ steps.info.outputs.pr_number }}"
           safe_title=$(printf '%s' "$title" | sed 's/|/\\|/g')
           safe_author=$(printf '%s' "$author" | sed 's/|/\\|/g')
-          if [ -n "$pr_number" ]; then
-            entry="- [${date_short}] ${safe_author}: ${safe_title} [#${pr_number}](${pr_url})"
-          else
-            entry="- [${date_short}] ${safe_author}: ${safe_title}"
-          fi
+          entry="- [${date_short}] ${safe_author}: ${safe_title} [#${pr_number}](${pr_url}) "
           echo "$entry" > changelog_entry.txt
           echo "changelog_entry_path=changelog_entry.txt" >> "$GITHUB_OUTPUT"
 
@@ -88,10 +62,15 @@ jobs:
             echo "" >> "$changelog_file"
           fi
           entry=$(cat "${{ steps.entry.outputs.changelog_entry_path }}")
-          # Ensure there is a header; append entry at the end of file separated by a blank line
-          printf "%s\n\n" "$entry" >> "$changelog_file"
+          # Se il file termina senza newline, assicurati separazione
+          tail_char=$(tail -c1 "$changelog_file" 2>/dev/null || true)
+          if [ -n "$tail_char" ] && [ "$tail_char" != $'\n' ]; then
+            printf "\n\n%s\n" "$entry" >> "$changelog_file"
+          else
+            printf "\n%s\n" "$entry" >> "$changelog_file"
+          fi
 
-      - name: Commit and push changelog to main
+      - name: Commit and push changelog to PR branch
         env:
           GIT_AUTHOR_NAME: github-actions
           GIT_AUTHOR_EMAIL: actions@github.com
@@ -103,6 +82,6 @@ jobs:
             echo "No changes to commit."
             exit 0
           fi
-          commit_msg="chore: append CHANGELOG entry for merge ${GITHUB_SHA::7}"
+          commit_msg="chore: update CHANGELOG for PR #${{ steps.info.outputs.pr_number }}"
           git commit -m "$commit_msg"
-          git push origin main
+          git push origin HEAD:${{ github.event.pull_request.head.ref }}

CHANGELOG.md

@@ -1,5 +1,9 @@
 # Changelog
 
+- [2025-11-01] DamImpr: Change changelog update from merge to PR event [#25](https://github.com/DamImpr/cache-multi-layer/pull/25) 
+
 - [2025-11-01] DamImpr: Change changelog entry format in workflow2 [#22](https://github.com/DamImpr/cache-multi-layer/pull/22)\ 
 
 ### 2025-10-31 — Remove blank line from entrypoint.sh\n\n- **Autore:** DamImpr\n- **PR:** [#20](https://github.com/DamImpr/cache-multi-layer/pull/20)\n
+
+- [2025-11-01] DamImpr: Change changelog update from merge to PR event [#25](https://github.com/DamImpr/cache-multi-layer/pull/25)