Use regex to skip unnecessary reference processing in ProcessCommitWorker

app/models/concerns/mentionable.rb

@@ -78,6 +78,8 @@ module Mentionable
   # Extract GFM references to other Mentionables from this Mentionable. Always excludes its #local_reference.
   def referenced_mentionables(current_user = self.author)
+    return [] unless matches_cross_reference_regex?
+
     refs = all_references(current_user)
     refs = (refs.issues + refs.merge_requests + refs.commits)
@@ -87,6 +89,20 @@ module Mentionable
     refs.reject { |ref| ref == local_reference }
   end
+  # Uses regex to quickly determine if mentionables might be referenced
+  # Allows heavy processing to be skipped
+  def matches_cross_reference_regex?
+    reference_pattern = if project.default_issues_tracker?
+                          ReferenceRegexes::DEFAULT_PATTERN
+                        else
+                          ReferenceRegexes::EXTERNAL_PATTERN
+                        end
+
+    self.class.mentionable_attrs.any? do |attr, _|
+      __send__(attr) =~ reference_pattern
+    end
+  end
+
   # Create a cross-reference Note for each GFM reference to another Mentionable found in the +mentionable_attrs+.
   def create_cross_references!(author = self.author, without = [])
     refs = referenced_mentionables(author)

app/models/concerns/mentionable/reference_regexes.rb

+module Mentionable
+  module ReferenceRegexes
+    def self.reference_pattern(link_patterns, issue_pattern)
+      Regexp.union(link_patterns,
+                   issue_pattern,
+                   Commit.reference_pattern,
+                   MergeRequest.reference_pattern)
+    end
+
+    DEFAULT_PATTERN = begin
+      issue_pattern = Issue.reference_pattern
+      link_patterns = Regexp.union([Issue, Commit, MergeRequest].map(&:link_reference_pattern))
+      reference_pattern(link_patterns, issue_pattern)
+    end
+
+    EXTERNAL_PATTERN = begin
+      issue_pattern = ExternalIssue.reference_pattern
+      link_patterns = URI.regexp(%w(http https))
+      reference_pattern(link_patterns, issue_pattern)
+    end
+  end
+end

app/services/git_push_service.rb

@@ -85,8 +85,10 @@ class GitPushService < BaseService
     default = is_default_branch?
     push_commits.last(PROCESS_COMMIT_LIMIT).each do |commit|
-      ProcessCommitWorker.
-        perform_async(project.id, current_user.id, commit.to_hash, default)
+      if commit.matches_cross_reference_regex?
+        ProcessCommitWorker.
+          perform_async(project.id, current_user.id, commit.to_hash, default)
+      end
     end
   end

app/workers/process_commit_worker.rb

@@ -23,6 +23,9 @@ class ProcessCommitWorker
     return unless user
     commit = build_commit(project, commit_hash)
+
+    return unless commit.matches_cross_reference_regex?
+
     author = commit.author || user
     process_commit_message(project, commit, user, author, default)

spec/models/concerns/mentionable_spec.rb

@@ -163,3 +163,52 @@ describe Issue, "Mentionable" do
     end
   end
 end
+
+describe Commit, 'Mentionable' do
+  let(:project) { create(:project, :public, :repository) }
+  let(:commit)  { project.commit }
+
+  describe '#matches_cross_reference_regex?' do
+    it "is false when message doesn't reference anything" do
+      allow(commit.raw).to receive(:message).and_return "WIP: Do something"
+
+      expect(commit.matches_cross_reference_regex?).to be false
+    end
+
+    it 'is true if issue #number mentioned in title' do
+      allow(commit.raw).to receive(:message).and_return "#1"
+
+      expect(commit.matches_cross_reference_regex?).to be true
+    end
+
+    it 'is true if references an MR' do
+      allow(commit.raw).to receive(:message).and_return "See merge request !12"
+
+      expect(commit.matches_cross_reference_regex?).to be true
+    end
+
+    it 'is true if references a commit' do
+      allow(commit.raw).to receive(:message).and_return "a1b2c3d4"
+
+      expect(commit.matches_cross_reference_regex?).to be true
+    end
+
+    it 'is true if issue referenced by url' do
+      issue = create(:issue, project: project)
+
+      allow(commit.raw).to receive(:message).and_return Gitlab::UrlBuilder.build(issue)
+
+      expect(commit.matches_cross_reference_regex?).to be true
+    end
+
+    context 'with external issue tracker' do
+      let(:project) { create(:jira_project) }
+
+      it 'is true if external issues referenced' do
+        allow(commit.raw).to receive(:message).and_return 'JIRA-123'
+
+        expect(commit.matches_cross_reference_regex?).to be true
+      end
+    end
+  end
+end

spec/services/git_push_service_spec.rb

@@ -622,12 +622,21 @@ describe GitPushService, services: true do
     it 'only schedules a limited number of commits' do
       allow(service).to receive(:push_commits).
-        and_return(Array.new(1000, double(:commit, to_hash: {})))
+        and_return(Array.new(1000, double(:commit, to_hash: {}, matches_cross_reference_regex?: true)))
       expect(ProcessCommitWorker).to receive(:perform_async).exactly(100).times
       service.process_commit_messages
     end
+
+    it "skips commits which don't include cross-references" do
+      allow(service).to receive(:push_commits).
+        and_return([double(:commit, to_hash: {}, matches_cross_reference_regex?: false)])
+
+      expect(ProcessCommitWorker).not_to receive(:perform_async)
+
+      service.process_commit_messages
+    end
   end
   def execute_service(project, user, oldrev, newrev, ref)

spec/workers/process_commit_worker_spec.rb

@@ -20,6 +20,14 @@ describe ProcessCommitWorker do
       worker.perform(project.id, -1, commit.to_hash)
     end
+    it 'does not process the commit when no issues are referenced' do
+      allow(worker).to receive(:build_commit).and_return(double(matches_cross_reference_regex?: false))
+
+      expect(worker).not_to receive(:process_commit_message)
+
+      worker.perform(project.id, user.id, commit.to_hash)
+    end
+
     it 'processes the commit message' do
       expect(worker).to receive(:process_commit_message).and_call_original