CI: Force changelog updates

Changelog updates are now required in MRs by default. If there is a
match for "\<skip.\?changelog\>" in the commit message, this will be
ignored.

$CI_COMMIT_MESSAGE mangles newlines so it's not possible to require the
string to be on its own line, that means it would also trigger within a
wall of text, which makes it less obvious.

Also, I wasn't able to find a CI variable which has the ref of the
branch the MR is set against, to build a tree-ish than spans over the
whole MR and not just HEAD.

Signed-off-by: Maxime “pep” Buquet <pep@bouah.net>

.gitlab-ci.yml

@@ -68,6 +68,38 @@ rustfmt:
     - if: $CI_PIPELINE_SOURCE == 'merge_request_event'
     - if: $CI_PIPELINE_SOURCE == 'push' && $CI_COMMIT_REF_NAME == 'main'
 
+changelog-update:
+  stage: lint
+  extends:
+    - .stable
+  # Check in the commit message for "skip.?changelog", if not present
+  # then check for changes in changelogs.
+  # XXX: It looks like $CI_COMMIT_MESSAGE mangles newlines so it's not
+  # possible to require the "skip.?changelog" string to be on its own line,
+  # that means it would also trigger within a wall of text. Not so obvious.
+  # TODO: Check the whole MR for updates in changelogs, not just the last
+  # commit.
+  script:
+    - apt update; apt install -y --no-install-recommends git python3
+    - echo $CI_COMMIT_MESSAGE
+    - |
+      /usr/bin/env python3 -c "
+      import os, re, subprocess, sys
+      if re.search(r'skip changelog', os.environ['CI_COMMIT_MESSAGE'], flags=re.I) is not None:
+          print('Changelog skipped.')
+          sys.exit(0)
+      foo=subprocess.run(['git', 'log', '-1', '--oneline'], capture_output=True).stdout
+      print(f'FOO1:\n {foo}')
+      diff=subprocess.run(['git', 'diff-tree', '--no-commit-id', '-r', 'HEAD'], capture_output=True).stdout
+      print(f'FOO2:\n {diff}')
+      if re.search(b'[AM]\\s+\\S*changelog', diff, flags=re.I) is None:
+          print('Please update the Changelog. Use \"skip-changelog\" in the commit message to skip this check.')
+          sys.exit(1)
+      print('Changelog has been updated as expected.')"
+  rules:
+    - if: $CI_PIPELINE_SOURCE == 'merge_request_event'
+    - if: $CI_PIPELINE_SOURCE == 'push' && $CI_COMMIT_REF_NAME == 'main'
+
 stable-test:
   extends:
     - .test

xmpp/ChangeLog

@@ -5,6 +5,8 @@ XXXX-YY-ZZ [ RELEASER <admin@localhost> ]
       - Agent::wait_for_events now return Vec<Event> and sets inner tokio_xmpp Client
         auto-reconnect to true... It is still aware of Event::Disconnected but should
         no longer have weird hanging state or panic (!436)
+    * CI:
+      - Enforce changelog updates in Gitlab CI.
 
 Version 0.6.0:
 2024-07-27 [ Maxime “pep” Buquet <pep@bouah.net> ]