ci: delete nightly pre-releases when an RC is published

An RC supersedes the nightly line: after the manually dispatched RC
release goes out, all nightly pre-releases are removed, mirroring the
superseded-nightly cleanup in pre-release.yml.

Author: leandromqrs

.github/workflows/release.yml

@@ -61,6 +61,24 @@ jobs:
           generate_release_notes: true
           prerelease: ${{ github.event_name == 'workflow_dispatch' }}
 
+      # An RC supersedes the nightly line: once a release candidate is out,
+      # the nightly pre-releases are removed like superseded nightlies are.
+      - name: Delete superseded nightly pre-releases
+        if: ${{ github.event_name == 'workflow_dispatch' }}
+        env:
+          GH_TOKEN: ${{ github.token }}
+        run: |
+          set -euo pipefail
+
+          gh release list \
+            --limit 1000 \
+            --json tagName,isPrerelease \
+            --jq '.[] | select(.isPrerelease and (.tagName | test("-nightly[0-9]+$"))) | .tagName' |
+            while IFS= read -r nightly_tag; do
+              gh release delete "$nightly_tag" --cleanup-tag --yes
+              echo "Deleted superseded nightly ${nightly_tag}." >> "$GITHUB_STEP_SUMMARY"
+            done
+
       - name: Create maintenance branch
         if: ${{ github.event_name == 'push' }}
         run: |

CONTRIBUTING.md

@@ -103,7 +103,7 @@ and adds a final version bump commit. For example, if `metadata.json` on `releas
 
 Release candidates are published alongside GNOME Shell RCs. Tags follow the pattern `v50-rc1`, `v50-rc2`, etc. RC releases are marked as **pre-releases** on GitHub.
 
-Pushing an RC tag does **not** publish anything. After pushing the tag, trigger the `Release` workflow manually (`workflow_dispatch`) and pass the tag name in the `tag` input. The workflow validates that the tag contains `-rc`, runs CI against it, and publishes the pre-release.
+Pushing an RC tag does **not** publish anything. After pushing the tag, trigger the `Release` workflow manually (`workflow_dispatch`) and pass the tag name in the `tag` input. The workflow validates that the tag contains `-rc`, runs CI against it, and publishes the pre-release. An RC supersedes the nightly line, so publishing one deletes all nightly pre-releases.
 
 ### Stable releases