build: automatically extract release note from NEWS upon releasing

.github/workflows/release.yml

@@ -1,17 +1,3 @@
-# The way this works is a little weird. But basically, the create-release job
-# runs purely to initialize the GitHub release itself. Once done, the upload
-# URL of the release is saved as an artifact.
-#
-# The build-release job runs only once create-release is finished. It gets
-# the release upload URL by downloading the corresponding artifact (which was
-# uploaded by create-release). It then builds the release executables for each
-# supported platform and attaches them as release assets to the previously
-# created release.
-#
-# The key here is that we create the release only once.
-#
-# Adapted from: https://github.com/BurntSushi/ripgrep/blob/master/.github/workflows/release.yml
-
 name: release
 on:
   push:
@@ -36,8 +22,11 @@ jobs:
       - name: Create source distribution
         # no unit tests yet
         run: meson dist -C builddir/ --no-tests
+      - name: Create release note
+        run: tools/extract_release_note.py NEWS ${{ github.workspace }}-release-note.txt
       - name: Release
         uses: softprops/action-gh-release@v1
         with:
           files: builddir/meson-dist/*
+          body_path: ${{ github.workspace }}-release-note.txt
 

tools/extract_release_note.py

@@ -0,0 +1,47 @@
+#!/usr/bin/env python3
+# SPDX-FileCopyrightText: 2022 Aetf <aetf@unlimited-code.works>
+#
+# SPDX-License-Identifier: MIT
+import re
+import inspect
+
+PTN_RELEASE_NOTE = re.compile(r'^CHANGES WITH.+$([\s\S]+?)^CHANGES WITH.+$', re.MULTILINE)
+
+
+def extract(src: str) -> str:
+    """Find section between the first and the next 'CHANGES WITH xx:' lines,
+    and strip common prefix whitespace
+    """
+    m = PTN_RELEASE_NOTE.search(src)
+    if m is not None:
+        return inspect.cleandoc(m.group(1)) + '\n'
+    else:
+        return ''
+
+
+def main():
+    import argparse
+    import sys
+
+    parser = argparse.ArgumentParser()
+    parser.add_argument(
+        'src',
+        type=argparse.FileType('r'),
+        nargs='?',
+        help='input NEWS',
+        default=sys.stdin,
+    )
+    parser.add_argument(
+        'dest',
+        type=argparse.FileType('w'),
+        nargs='?',
+        help='output',
+        default=sys.stdout,
+    )
+    args = parser.parse_args()
+
+    args.dest.write(extract(args.src.read()))
+
+
+if __name__ == '__main__':
+    main()