Add scripts/update-changelog.sh

scripts/update-changelog.sh

@@ -0,0 +1,65 @@
+#! /bin/sh
+
+# This script automates generating changelog with `scripts/github-changelog.cr`,
+# editing it into `CHANGELOG.md` and pushing it to a `changelog/$VERSION` branch.
+#
+# It reads the current (dev-)version from `src/VERSION` and generates the
+# changelog entries for all PRs from the respective GitHub milestone via
+# `scripts/github-changelog.cr`.
+# The section is then inserted into `CHANGELOG.md`, overwriting any previous
+# content for this milestone.
+# Finally, the changes are commited and pushed to `changelog/$VERSION`.
+# If the changelog section is *new*, also creates a draft PR for this branch.
+#
+# Usage:
+#
+#   scripts/update-changelog.sh
+#
+# Requirements:
+#
+#   - scripts/github-changelog.cr
+#   - git
+#   - grep
+#   - sed
+#
+# Environment variables:
+#   GITHUB_TOKEN: Access token for the GitHub API (required)
+
+set -eu
+
+VERSION=${1:-$(cat src/VERSION)}
+VERSION=${VERSION%-dev}
+
+base_branch=$(git rev-parse --abbrev-ref HEAD)
+branch="changelog/$VERSION"
+current_changelog="CHANGELOG.$VERSION.md"
+
+echo "Generating $current_changelog..."
+scripts/github-changelog.cr $VERSION > $current_changelog
+
+echo "Switching to branch $branch"
+git switch $branch 2>/dev/null || git switch -c $branch;
+
+if grep --silent -E "^## \[$VERSION\]" CHANGELOG.md; then
+  echo "Replacing section in CHANGELOG"
+
+  sed -i -E "/^## \[$VERSION\]/,/^## /{
+    /^## \[$VERSION\]/s/.*/cat $current_changelog/e; /^## /!d
+  }" CHANGELOG.md
+
+  git add CHANGELOG.md
+  git commit -m "Update changelog for $VERSION"
+  git push
+else
+  echo "Adding new section to CHANGELOG"
+
+  sed -i -E "2r $current_changelog" CHANGELOG.md
+
+  git add CHANGELOG.md
+  git commit -m "Add changelog for $VERSION"
+  git push -u upstream $branch
+
+  gh pr create --draft --base "$base_branch" \
+    --body "Preview: https://github.com/crystal-lang/crystal/blob/$branch/CHANGELOG.md" \
+    --label "topic:infrastructure" -t "Changelog for $VERSION" --milestone "$VERSION"
+fi