Separate the release steps from the bump tool

tools/release.sh

@@ -0,0 +1,62 @@
+#!/usr/bin/env bash
+#
+# According to the GitLab flow release branching model,
+# cherry-pick the last commit on the main branch to the release branch,
+# and then create a tag and gem package on the release branch (naming format: 'release/<X.Y>').
+#
+#
+# Usage:
+#
+#   It can be run on main branch, and it should be used after just finishing the last feature in the version plan,
+#   or just after merging the hotfix to the main branch.
+#
+# Requires: Git, Gulp
+
+set -eu
+
+GEM_SPEC="jekyll-theme-chirpy.gemspec"
+
+check() {
+  if [[ -n $(git status . -s) ]]; then
+    echo "Error: Commit unstaged files first, and then run this tool againt."
+    exit -1
+  fi
+
+  if [[ ! -f $GEM_SPEC ]]; then
+    echo -e "Error: Missing file \"$GEM_SPEC\"!\n"
+    exit -1
+  fi
+}
+
+release() {
+  _default_branch="$(git symbolic-ref refs/remotes/origin/HEAD | sed 's@^refs/remotes/origin/@@')"
+  _version="$(grep "spec.version" jekyll-theme-chirpy.gemspec | sed 's/.*= "//;s/".*//')" # X.Y.Z
+  _release_branch="release/${_version%.*}"
+
+  if [[ -z $(git branch -v | grep "$_release_branch") ]]; then
+    # create a new release branch
+    git checkout -b "$_release_branch"
+  else
+    # cherry-pick the latest commit from default branch to release branch
+    _last_commit="$(git rev-parse "$_default_branch")"
+    git checkout "$_release_branch"
+    git cherry-pick "$_last_commit" -m 1
+  fi
+
+  # create new tag
+  echo -e "Create tag v$_version\n"
+  git tag "v$_version"
+
+  # build a gem package
+  echo -e "Build the gem pakcage for v$_version\n"
+  rm -f ./*.gem
+  gem build "$GEM_SPEC"
+
+}
+
+main() {
+  check
+  release
+}
+
+main