Improve changelog entry checks using Danger

Check if the changelog entry matches the MR title, and if the web url is
listed in the change, so no typo's can be made.

For speed we're using a slightly different container.

Fixes https://gitlab.com/gitlab-org/gitaly/issues/1176

1 files changed, 18 insertions, 2 deletions

diff --git a/Dangerfile b/Dangerfile
index b3845f894..3afa7a26d 100644
--- a/Dangerfile
+++ b/Dangerfile
@@ -1,7 +1,23 @@
-unless git.modified_files.include?("CHANGELOG.md")
-  warn("This MR is missing a CHANGELOG entry")
+CHANGELOG_FILE = "CHANGELOG.md"
+
+def check_changelog
+  unless git.modified_files.include?(CHANGELOG_FILE)
+    warn("This MR is missing a CHANGELOG entry")
+    return
+  end
+
+  patch = git.diff_for_file(CHANGELOG_FILE).patch
+  unless patch.match?(/^\+- #{Regexp.quote(gitlab.mr_title)}\n/)
+    fail('Changelog entry should match the MR title')
+  end
+
+  unless patch.match?(/^\+\s+#{Regexp.quote(gitlab.mr_json['web_url'])}\n/)
+    fail('Changelog entry URL does not match the web url')
+  end
 end
 
+check_changelog
+
 fail("Please provide a MR description") if gitlab.mr_body.empty?
 
 VENDOR_JSON = 'vendor/vendor.json'