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, 59 insertions, 0 deletions

diff --git a/lib/gitlab/reference_extractor.rb b/lib/gitlab/reference_extractor.rb
new file mode 100644
index 00000000000..94b01e808d9
--- /dev/null
+++ b/lib/gitlab/reference_extractor.rb
@@ -0,0 +1,59 @@
+module Gitlab
+  # Extract possible GFM references from an arbitrary String for further processing.
+  class ReferenceExtractor
+    attr_accessor :users, :issues, :merge_requests, :snippets, :commits
+
+    include Markdown
+
+    def initialize
+      @users, @issues, @merge_requests, @snippets, @commits = [], [], [], [], []
+    end
+
+    def analyze string
+      parse_references(string.dup)
+    end
+
+    # Given a valid project, resolve the extracted identifiers of the requested type to
+    # model objects.
+
+    def users_for project
+      users.map do |identifier|
+        project.users.where(username: identifier).first
+      end.reject(&:nil?)
+    end
+
+    def issues_for project
+      issues.map do |identifier|
+        project.issues.where(iid: identifier).first
+      end.reject(&:nil?)
+    end
+
+    def merge_requests_for project
+      merge_requests.map do |identifier|
+        project.merge_requests.where(iid: identifier).first
+      end.reject(&:nil?)
+    end
+
+    def snippets_for project
+      snippets.map do |identifier|
+        project.snippets.where(id: identifier).first
+      end.reject(&:nil?)
+    end
+
+    def commits_for project
+      repo = project.repository
+      return [] if repo.nil?
+
+      commits.map do |identifier|
+        repo.commit(identifier)
+      end.reject(&:nil?)
+    end
+
+    private
+
+    def reference_link type, identifier
+      # Append identifier to the appropriate collection.
+      send("#{type}s") << identifier
+    end
+  end
+end