ci: auto generate changelog

.github/workflows/release.yml

@@ -0,0 +1,104 @@
+name: release
+
+on:
+  push:
+    tags:
+      - "v*"
+
+permissions:
+  contents: write
+
+jobs:
+  release:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+          fetch-tags: true
+
+      - name: Generate changelog
+        id: changelog
+        run: |
+          set -euo pipefail
+          TAG="${GITHUB_REF_NAME}"
+          REPO="${GITHUB_REPOSITORY}"
+
+          # previous tag (parent of this tag)
+          PREV_TAG="$(git describe --tags --abbrev=0 HEAD^ 2>/dev/null || echo "")"
+
+          if [ -z "$PREV_TAG" ]; then
+            RANGE="HEAD"
+            echo "No previous tag, using all history"
+          else
+            RANGE="${PREV_TAG}..HEAD"
+            echo "Range: $RANGE"
+          fi
+
+          FEATS=""
+          FIXES=""
+
+          # %H = hash, %s = subject (first line)
+          while IFS= read -r line; do
+            [ -z "$line" ] && continue
+            sha="${line%% *}"
+            subject="${line#* }"
+            # match conventional commits: feat, fix (with optional scope)
+            if echo "$subject" | grep -qE '^(feat|fix)(\(.+\))?: '; then
+              type="$(echo "$subject" | sed -E 's/^([a-z]+)(\(.+\))?:.*/\1/')"
+              # strip type prefix for display, keep rest as title
+              title="$(echo "$subject" | sed -E 's/^[a-z]+(\(.+\))?: //')"
+              short="$(echo "$sha" | cut -c1-7)"
+              url="https://github.com/${REPO}/commit/${sha}"
+              entry="- ${title} ([\`${short}\`](${url}))"
+              if [ "$type" = "feat" ]; then
+                FEATS="${FEATS}${entry}"$'\n'
+              elif [ "$type" = "fix" ]; then
+                FIXES="${FIXES}${entry}"$'\n'
+              fi
+            fi
+          done < <(git log "$RANGE" --pretty=format:"%H %s" --no-merges)
+
+          {
+            echo "# ${TAG}"
+            echo ""
+            if [ -n "$FEATS" ]; then
+              echo "## Features"
+              echo ""
+              printf "%s" "$FEATS"
+              echo ""
+            fi
+            if [ -n "$FIXES" ]; then
+              echo "## Fixes"
+              echo ""
+              printf "%s" "$FIXES"
+              echo ""
+            fi
+            if [ -z "$FEATS" ] && [ -z "$FIXES" ]; then
+              echo "_No relevant conventional commits (feat/fix) in this release._"
+              echo ""
+            fi
+            echo "---"
+            echo ""
+            if [ -n "$PREV_TAG" ]; then
+              echo "**Full diff:** [\`${PREV_TAG}...${TAG}\`](https://github.com/${REPO}/compare/${PREV_TAG}...${TAG})"
+            else
+              echo "**Full history up to ${TAG}**"
+            fi
+          } > /tmp/notes.md
+
+          cat /tmp/notes.md
+          # multiline output for next step
+          {
+            echo "notes<<EOF"
+            cat /tmp/notes.md
+            echo "EOF"
+          } >> "$GITHUB_OUTPUT"
+
+      - name: Create GitHub Release
+        uses: softprops/action-gh-release@v2
+        with:
+          tag_name: ${{ github.ref_name }}
+          name: ${{ github.ref_name }}
+          body: ${{ steps.changelog.outputs.notes }}
+          generate_release_notes: false