Link issues from comments and automatically close them

Any mention of Issues, MergeRequests, or Commits via GitLab-flavored markdown
references in descriptions, titles, or attached Notes creates a back-reference
Note that links to the original referencer. Furthermore, pushing commits with
commit messages that match a (configurable) regexp to a project's default
branch will close any issues mentioned by GFM in the matched closing phrase.
If accepting a merge request would close any Issues in this way, a banner is
appended to the merge request's main panel to indicate this.

1 files changed, 26 insertions, 0 deletions

diff --git a/app/models/commit.rb b/app/models/commit.rb
index da80c2940ff..f8ca6a5fe82 100644
--- a/app/models/commit.rb
+++ b/app/models/commit.rb
@@ -2,6 +2,9 @@ class Commit
   include ActiveModel::Conversion
   include StaticModel
   extend ActiveModel::Naming
+  include Mentionable
+
+  attr_mentionable :safe_message
 
   # Safe amount of files with diffs in one commit to render
   # Used to prevent 500 error on huge commits by suppressing diff
@@ -65,6 +68,29 @@ class Commit
     end
   end
 
+  # Regular expression that identifies commit message clauses that trigger issue closing.
+  def issue_closing_regex
+    @issue_closing_regex ||= Regexp.new(Gitlab.config.gitlab.issue_closing_pattern)
+  end
+
+  # Discover issues should be closed when this commit is pushed to a project's
+  # default branch.
+  def closes_issues project
+    md = issue_closing_regex.match(safe_message)
+    if md
+      extractor = Gitlab::ReferenceExtractor.new
+      extractor.analyze(md[0])
+      extractor.issues_for(project)
+    else
+      []
+    end
+  end
+
+  # Mentionable override.
+  def gfm_reference
+    "commit #{sha[0..5]}"
+  end
+
   def method_missing(m, *args, &block)
     @raw.send(m, *args, &block)
   end