ci: make release workflow idempotent [4.x]

.github/workflows/release.yml

@@ -18,23 +18,29 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      - name: Checkout code
-        uses: actions/checkout@v6
-
-      - name: Determine if pre-release
-        id: prerelease
+      - name: Determine release flags
+        id: flags
+        env:
+          TAG: ${{ github.ref_name }}
         run: |
-          TAG="${{ github.ref_name }}"
           if [[ "$TAG" == *"-"* ]]; then
-            echo "flag=--prerelease" >> $GITHUB_OUTPUT
+            echo "prerelease=--prerelease" >> "$GITHUB_OUTPUT"
           else
-            echo "flag=" >> $GITHUB_OUTPUT
+            echo "prerelease=" >> "$GITHUB_OUTPUT"
           fi
 
       - name: Create GitHub Release
-        run: gh release create "${{ github.ref_name }}" --generate-notes ${{ steps.prerelease.outputs.flag }}
         env:
           GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+          GH_REPO: ${{ github.repository }}
+          TAG: ${{ github.ref_name }}
+          PRERELEASE_FLAG: ${{ steps.flags.outputs.prerelease }}
+        run: |
+          if gh release view "$TAG" >/dev/null 2>&1; then
+            echo "Release $TAG already exists, skipping creation."
+            exit 0
+          fi
+          gh release create "$TAG" --generate-notes $PRERELEASE_FLAG
 
   cleanup:
     needs: tests
@@ -44,8 +50,9 @@ jobs:
       contents: write
 
     steps:
-      - name: Checkout code
-        uses: actions/checkout@v6
-
       - name: Delete tag on test failure
-        run: git push --delete origin "${{ github.ref_name }}"
+        env:
+          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+          GH_REPO: ${{ github.repository }}
+          TAG: ${{ github.ref_name }}
+        run: gh api -X DELETE "repos/$GH_REPO/git/refs/tags/$TAG"