Partially automate release changelog

.github/workflows/ci.yml

@@ -60,6 +60,9 @@ jobs:
       - name: Download Artifacts
         uses: actions/download-artifact@v2
 
+      - name: Generate changelog
+        run: . scripts/generate_changelog.sh
+
       - name: Create Release
         id: create-release
         uses: actions/create-release@v1
@@ -68,6 +71,7 @@ jobs:
         with:
           tag_name: ${{ github.ref }}
           release_name: Release ${{ github.ref }}
+          body: ${{ env.GENERATED_CHANGELOG }}
           draft: true
           prerelease: false
 

scripts/generate_changelog.sh

@@ -0,0 +1,67 @@
+#!/bin/bash
+#
+# Copyright (C) 2011-2021 lishid. All rights reserved.
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, version 3.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.
+#
+
+# A script for generating a changelog from Git.
+#
+# Note that this script is designed for use in GitHub Actions, and is not
+# particularly robust nor configurable. Run from project parent directory.
+
+# Query GitHub for the username of the given email address.
+# Falls through to the given author name.
+lookup_email_username() {
+  lookup=$(curl -G --data-urlencode "q=$1 in:email" https://api.github.com/search/users -H 'Accept: application/vnd.github.v3+json' | grep '"login":' | sed -e 's/^.*": "//g' -e 's/",.*$//g')
+
+  if [[ $lookup ]]; then
+    echo -n "@$lookup"
+  else
+    echo "$2"
+  fi
+}
+
+# Use formatted log to pull authors list
+authors_raw=$(git log --pretty=format:"%ae|%an" "$(git describe --tags --abbrev=0 @^)"..@)
+readarray -t authors <<<"$authors_raw"
+
+declare -A author_data
+
+for author in "${authors[@]}"; do
+  # Match author email
+  author_email=${author%|*}
+  # Convert to lower case
+  author_email=${author_email,,}
+  # Match author name
+  author_name=${author##*|}
+  if [[ -n ${author_data[$author_email]} ]]; then
+    # Skip emails we already have data for
+    continue
+  fi
+
+  # Fetch and store author GitHub username by email
+  author_data[$author_email]=$(lookup_email_username "$author_email" "$author_name")
+done
+
+# Fetch actual formatted changelog
+changelog=$(git log --pretty=format:"%s (%h) - %ae" "$(git describe --tags --abbrev=0 @^)"..@)
+
+for author_email in "${!author_data[@]}"; do
+  # Ignore case when matching
+  shopt -s nocasematch
+  # Match and replace email
+  changelog=${changelog//$author_email/${author_data[$author_email]}}
+done
+
+echo "GENERATED_CHANGELOG<<EOF${changelog}EOF" >> "$GITHUB_ENV"