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.

12 files changed, 570 insertions, 18 deletions

diff --git a/spec/lib/gitlab/reference_extractor_spec.rb b/spec/lib/gitlab/reference_extractor_spec.rb
new file mode 100644
index 00000000000..7d805f8c72a
--- /dev/null
+++ b/spec/lib/gitlab/reference_extractor_spec.rb
@@ -0,0 +1,95 @@
+require 'spec_helper'
+
+describe Gitlab::ReferenceExtractor do
+  it 'extracts username references' do
+    subject.analyze "this contains a @user reference"
+    subject.users.should == ["user"]
+  end
+
+  it 'extracts issue references' do
+    subject.analyze "this one talks about issue #1234"
+    subject.issues.should == ["1234"]
+  end
+
+  it 'extracts merge request references' do
+    subject.analyze "and here's !43, a merge request"
+    subject.merge_requests.should == ["43"]
+  end
+
+  it 'extracts snippet ids' do
+    subject.analyze "snippets like $12 get extracted as well"
+    subject.snippets.should == ["12"]
+  end
+
+  it 'extracts commit shas' do
+    subject.analyze "commit shas 98cf0ae3 are pulled out as Strings"
+    subject.commits.should == ["98cf0ae3"]
+  end
+
+  it 'extracts multiple references and preserves their order' do
+    subject.analyze "@me and @you both care about this"
+    subject.users.should == ["me", "you"]
+  end
+
+  it 'leaves the original note unmodified' do
+    text = "issue #123 is just the worst, @user"
+    subject.analyze text
+    text.should == "issue #123 is just the worst, @user"
+  end
+
+  it 'handles all possible kinds of references' do
+    accessors = Gitlab::Markdown::TYPES.map { |t| "#{t}s".to_sym }
+    subject.should respond_to(*accessors)
+  end
+
+  context 'with a project' do
+    let(:project) { create(:project_with_code) }
+
+    it 'accesses valid user objects on the project team' do
+      @u_foo = create(:user, username: 'foo')
+      @u_bar = create(:user, username: 'bar')
+      create(:user, username: 'offteam')
+
+      project.team << [@u_foo, :reporter]
+      project.team << [@u_bar, :guest]
+
+      subject.analyze "@foo, @baduser, @bar, and @offteam"
+      subject.users_for(project).should == [@u_foo, @u_bar]
+    end
+
+    it 'accesses valid issue objects' do
+      @i0 = create(:issue, project: project)
+      @i1 = create(:issue, project: project)
+
+      subject.analyze "##{@i0.iid}, ##{@i1.iid}, and #999."
+      subject.issues_for(project).should == [@i0, @i1]
+    end
+
+    it 'accesses valid merge requests' do
+      @m0 = create(:merge_request, source_project: project, target_project: project, source_branch: 'aaa')
+      @m1 = create(:merge_request, source_project: project, target_project: project, source_branch: 'bbb')
+
+      subject.analyze "!999, !#{@m1.iid}, and !#{@m0.iid}."
+      subject.merge_requests_for(project).should == [@m1, @m0]
+    end
+
+    it 'accesses valid snippets' do
+      @s0 = create(:project_snippet, project: project)
+      @s1 = create(:project_snippet, project: project)
+      @s2 = create(:project_snippet)
+
+      subject.analyze "$#{@s0.id}, $999, $#{@s2.id}, $#{@s1.id}"
+      subject.snippets_for(project).should == [@s0, @s1]
+    end
+
+    it 'accesses valid commits' do
+      commit = project.repository.commit("master")
+
+      subject.analyze "this references commits #{commit.sha[0..6]} and 012345"
+      extracted = subject.commits_for(project)
+      extracted.should have(1).item
+      extracted[0].sha.should == commit.sha
+      extracted[0].message.should == commit.message
+    end
+  end
+end
diff --git a/spec/models/commit_spec.rb b/spec/models/commit_spec.rb
index 73418efd3f2..fa556f94a1d 100644
--- a/spec/models/commit_spec.rb
+++ b/spec/models/commit_spec.rb
@@ -1,7 +1,8 @@
 require 'spec_helper'
 
 describe Commit do
-  let(:commit) { create(:project_with_code).repository.commit }
+  let(:project) { create :project_with_code }
+  let(:commit) { project.repository.commit }
 
   describe '#title' do
     it "returns no_commit_message when safe_message is blank" do
@@ -46,4 +47,23 @@ describe Commit do
     it { should respond_to(:id) }
     it { should respond_to(:to_patch) }
   end
+
+  describe '#closes_issues' do
+    let(:issue) { create :issue, project: project }
+
+    it 'detects issues that this commit is marked as closing' do
+      commit.stub(issue_closing_regex: /^([Cc]loses|[Ff]ixes) #\d+/, safe_message: "Fixes ##{issue.iid}")
+      commit.closes_issues(project).should == [issue]
+    end
+  end
+
+  it_behaves_like 'a mentionable' do
+    let(:subject) { commit }
+    let(:mauthor) { create :user, email: commit.author_email }
+    let(:backref_text) { "commit #{subject.sha[0..5]}" }
+    let(:set_mentionable_text) { ->(txt){ subject.stub(safe_message: txt) } }
+
+    # Include the subject in the repository stub.
+    let(:extra_commits) { [subject] }
+  end
 end
diff --git a/spec/models/issue_spec.rb b/spec/models/issue_spec.rb
index c10891331b1..75155d5dc1d 100644
--- a/spec/models/issue_spec.rb
+++ b/spec/models/issue_spec.rb
@@ -56,4 +56,10 @@ describe Issue do
       Issue.open_for(user).count.should eq 2
     end
   end
+
+  it_behaves_like 'an editable mentionable' do
+    let(:subject) { create :issue, project: mproject }
+    let(:backref_text) { "issue ##{subject.iid}" }
+    let(:set_mentionable_text) { ->(txt){ subject.description = txt } }
+  end
 end
diff --git a/spec/models/merge_request_spec.rb b/spec/models/merge_request_spec.rb
index 40931513af6..18c32d4fb74 100644
--- a/spec/models/merge_request_spec.rb
+++ b/spec/models/merge_request_spec.rb
@@ -43,7 +43,6 @@ describe MergeRequest do
     it { should include_module(Issuable) }
   end
 
-
   describe "#mr_and_commit_notes" do
     let!(:merge_request) { create(:merge_request) }
 
@@ -104,4 +103,34 @@ describe MergeRequest do
     end
   end
 
+  describe 'detection of issues to be closed' do
+    let(:issue0) { create :issue, project: subject.project }
+    let(:issue1) { create :issue, project: subject.project }
+    let(:commit0) { mock('commit0', closes_issues: [issue0]) }
+    let(:commit1) { mock('commit1', closes_issues: [issue0]) }
+    let(:commit2) { mock('commit2', closes_issues: [issue1]) }
+
+    before do
+      subject.stub(unmerged_commits: [commit0, commit1, commit2])
+    end
+
+    it 'accesses the set of issues that will be closed on acceptance' do
+      subject.project.default_branch = subject.target_branch
+
+      subject.closes_issues.should == [issue0, issue1].sort_by(&:id)
+    end
+
+    it 'only lists issues as to be closed if it targets the default branch' do
+      subject.project.default_branch = 'master'
+      subject.target_branch = 'something-else'
+
+      subject.closes_issues.should be_empty
+    end
+  end
+
+  it_behaves_like 'an editable mentionable' do
+    let(:subject) { create :merge_request, source_project: mproject, target_project: mproject }
+    let(:backref_text) { "merge request !#{subject.iid}" }
+    let(:set_mentionable_text) { ->(txt){ subject.title = txt } }
+  end
 end
diff --git a/spec/models/note_spec.rb b/spec/models/note_spec.rb
index 646255543a0..ef143debcc1 100644
--- a/spec/models/note_spec.rb
+++ b/spec/models/note_spec.rb
@@ -72,7 +72,6 @@ describe Note do
   end
 
   let(:project) { create(:project) }
-  let(:commit) { project.repository.commit }
 
   describe "Commit notes" do
     let!(:note) { create(:note_on_commit, note: "+1 from me") }
@@ -131,7 +130,7 @@ describe Note do
   describe "Merge request notes" do
     let!(:note) { create(:note_on_merge_request, note: "+1 from me") }
 
-    it "should not be votable" do
+    it "should be votable" do
       note.should be_votable
     end
   end
@@ -150,7 +149,7 @@ describe Note do
     let(:author) { create(:user) }
     let(:status) { 'new_status' }
 
-    subject { Note.create_status_change_note(thing, project, author, status) }
+    subject { Note.create_status_change_note(thing, project, author, status, nil) }
 
     it 'creates and saves a Note' do
       should be_a Note
@@ -161,6 +160,102 @@ describe Note do
     its(:project) { should == thing.project }
     its(:author) { should == author }
     its(:note) { should =~ /Status changed to #{status}/ }
+
+    it 'appends a back-reference if a closing mentionable is supplied' do
+      commit = double('commit', gfm_reference: 'commit 123456')
+      n = Note.create_status_change_note(thing, project, author, status, commit)
+
+      n.note.should =~ /Status changed to #{status} by commit 123456/
+    end
+  end
+
+  describe '#create_cross_reference_note' do
+    let(:project)    { create(:project_with_code) }
+    let(:author)     { create(:user) }
+    let(:issue)      { create(:issue, project: project) }
+    let(:mergereq)   { create(:merge_request, target_project: project) }
+    let(:commit)     { project.repository.commit }
+
+    # Test all of {issue, merge request, commit} in both the referenced and referencing
+    # roles, to ensure that the correct information can be inferred from any argument.
+
+    context 'issue from a merge request' do
+      subject { Note.create_cross_reference_note(issue, mergereq, author, project) }
+
+      it { should be_valid }
+      its(:noteable) { should == issue }
+      its(:project)  { should == issue.project }
+      its(:author)   { should == author }
+      its(:note) { should == "_mentioned in merge request !#{mergereq.iid}_" }
+    end
+
+    context 'issue from a commit' do
+      subject { Note.create_cross_reference_note(issue, commit, author, project) }
+
+      it { should be_valid }
+      its(:noteable) { should == issue }
+      its(:note) { should == "_mentioned in commit #{commit.sha[0..5]}_" }
+    end
+
+    context 'merge request from an issue' do
+      subject { Note.create_cross_reference_note(mergereq, issue, author, project) }
+
+      it { should be_valid }
+      its(:noteable) { should == mergereq }
+      its(:project) { should == mergereq.project }
+      its(:note) { should == "_mentioned in issue ##{issue.iid}_" }
+    end
+
+    context 'commit from a merge request' do
+      subject { Note.create_cross_reference_note(commit, mergereq, author, project) }
+
+      it { should be_valid }
+      its(:noteable) { should == commit }
+      its(:project) { should == project }
+      its(:note) { should == "_mentioned in merge request !#{mergereq.iid}_" }
+    end
+  end
+
+  describe '#cross_reference_exists?' do
+    let(:project) { create :project }
+    let(:author) { create :user }
+    let(:issue) { create :issue }
+    let(:commit0) { double 'commit0', gfm_reference: 'commit 123456' }
+    let(:commit1) { double 'commit1', gfm_reference: 'commit 654321' }
+
+    before do
+      Note.create_cross_reference_note(issue, commit0, author, project)
+    end
+
+    it 'detects if a mentionable has already been mentioned' do
+      Note.cross_reference_exists?(issue, commit0).should be_true
+    end
+
+    it 'detects if a mentionable has not already been mentioned' do
+      Note.cross_reference_exists?(issue, commit1).should be_false
+    end
+  end
+
+  describe '#system?' do
+    let(:project) { create(:project) }
+    let(:issue)   { create(:issue, project: project) }
+    let(:other)   { create(:issue, project: project) }
+    let(:author)  { create(:user) }
+
+    it 'should recognize user-supplied notes as non-system' do
+      @note = create(:note_on_issue)
+      @note.should_not be_system
+    end
+
+    it 'should identify status-change notes as system notes' do
+      @note = Note.create_status_change_note(issue, project, author, 'closed', nil)
+      @note.should be_system
+    end
+
+    it 'should identify cross-reference notes as system notes' do
+      @note = Note.create_cross_reference_note(issue, other, author, project)
+      @note.should be_system
+    end
   end
 
   describe :authorization do
@@ -208,4 +303,11 @@ describe Note do
       it { @abilities.allowed?(@u3, :admin_note, @p1).should be_false }
     end
   end
+
+  it_behaves_like 'an editable mentionable' do
+    let(:issue) { create :issue, project: project }
+    let(:subject) { create :note, noteable: issue, project: project }
+    let(:backref_text) { issue.gfm_reference }
+    let(:set_mentionable_text) { ->(txt) { subject.note = txt } }
+  end
 end
diff --git a/spec/observers/activity_observer_spec.rb b/spec/observers/activity_observer_spec.rb
index 78837552438..dc14ab86b6d 100644
--- a/spec/observers/activity_observer_spec.rb
+++ b/spec/observers/activity_observer_spec.rb
@@ -3,6 +3,8 @@ require 'spec_helper'
 describe ActivityObserver do
   let(:project)  { create(:project) }
 
+  before { Thread.current[:current_user] = create(:user) }
+
   def self.it_should_be_valid_event
     it { @event.should_not be_nil }
     it { @event.project.should == project }
@@ -34,4 +36,26 @@ describe ActivityObserver do
     it { @event.action.should == Event::COMMENTED }
     it { @event.target.should == @note }
   end
+
+  describe "Ignore system notes" do
+    let(:author) { create(:user) }
+    let!(:issue) { create(:issue, project: project) }
+    let!(:other) { create(:issue) }
+
+    it "should not create events for status change notes" do
+      expect do
+        Note.observers.enable :activity_observer do
+          Note.create_status_change_note(issue, project, author, 'reopened', nil)
+        end
+      end.to_not change { Event.count }
+    end
+
+    it "should not create events for cross-reference notes" do
+      expect do
+        Note.observers.enable :activity_observer do
+          Note.create_cross_reference_note(issue, other, author, issue.project)
+        end
+      end.to_not change { Event.count }
+    end
+  end
 end
diff --git a/spec/observers/issue_observer_spec.rb b/spec/observers/issue_observer_spec.rb
index c9e88aee1a5..4155ff31193 100644
--- a/spec/observers/issue_observer_spec.rb
+++ b/spec/observers/issue_observer_spec.rb
@@ -8,8 +8,9 @@ describe IssueObserver do
 
 
   before { subject.stub(:current_user).and_return(some_user) }
+  before { subject.stub(:current_commit).and_return(nil) }
   before { subject.stub(notification: mock('NotificationService').as_null_object) }
-
+  before { mock_issue.project.stub_chain(:repository, :commit).and_return(nil) }
 
   subject { IssueObserver.instance }
 
@@ -19,6 +20,15 @@ describe IssueObserver do
 
       subject.after_create(mock_issue)
     end
+
+    it 'should create cross-reference notes' do
+      other_issue = create(:issue)
+      mock_issue.stub(references: [other_issue])
+
+      Note.should_receive(:create_cross_reference_note).with(other_issue, mock_issue,
+        some_user, mock_issue.project)
+      subject.after_create(mock_issue)
+    end
   end
 
   context '#after_close' do
@@ -26,7 +36,7 @@ describe IssueObserver do
       before { mock_issue.stub(state: 'closed') }
 
       it 'note is created if the issue is being closed' do
-        Note.should_receive(:create_status_change_note).with(mock_issue, mock_issue.project, some_user, 'closed')
+        Note.should_receive(:create_status_change_note).with(mock_issue, mock_issue.project, some_user, 'closed', nil)
 
         subject.after_close(mock_issue, nil)
       end
@@ -35,13 +45,23 @@ describe IssueObserver do
         subject.notification.should_receive(:close_issue).with(mock_issue, some_user)
         subject.after_close(mock_issue, nil)
       end
+
+      it 'appends a mention to the closing commit if one is present' do
+        commit = double('commit', gfm_reference: 'commit 123456')
+        subject.stub(current_commit: commit)
+
+        Note.should_receive(:create_status_change_note).with(mock_issue, mock_issue.project, some_user, 'closed', commit)
+
+        subject.after_close(mock_issue, nil)
+      end
     end
 
     context 'a status "reopened"' do
       before { mock_issue.stub(state: 'reopened') }
 
       it 'note is created if the issue is being reopened' do
-        Note.should_receive(:create_status_change_note).with(mock_issue, mock_issue.project, some_user, 'reopened')
+        Note.should_receive(:create_status_change_note).with(mock_issue, mock_issue.project, some_user, 'reopened', nil)
+
         subject.after_reopen(mock_issue, nil)
       end
     end
@@ -67,5 +87,13 @@ describe IssueObserver do
         subject.after_update(mock_issue)
       end
     end
+
+    context 'cross-references' do
+      it 'notices added references' do
+        mock_issue.should_receive(:notice_added_references)
+
+        subject.after_update(mock_issue)
+      end
+    end
   end
 end
diff --git a/spec/observers/merge_request_observer_spec.rb b/spec/observers/merge_request_observer_spec.rb
index 3d6fff9c24e..3f5250a0040 100644
--- a/spec/observers/merge_request_observer_spec.rb
+++ b/spec/observers/merge_request_observer_spec.rb
@@ -5,15 +5,20 @@ describe MergeRequestObserver do
   let(:assignee) { create :user }
   let(:author) { create :user }
   let(:mr_mock) { double(:merge_request, id: 42, assignee: assignee, author: author) }
-  let(:assigned_mr) { create(:merge_request, assignee: assignee, author: author) }
-  let(:unassigned_mr) { create(:merge_request, author: author) }
-  let(:closed_assigned_mr) { create(:closed_merge_request, assignee: assignee, author: author) }
-  let(:closed_unassigned_mr) { create(:closed_merge_request, author: author) }
+  let(:assigned_mr) { create(:merge_request, assignee: assignee, author: author, target_project: create(:project)) }
+  let(:unassigned_mr) { create(:merge_request, author: author, target_project: create(:project)) }
+  let(:closed_assigned_mr) { create(:closed_merge_request, assignee: assignee, author: author, target_project: create(:project)) }
+  let(:closed_unassigned_mr) { create(:closed_merge_request, author: author, target_project: create(:project)) }
 
   before { subject.stub(:current_user).and_return(some_user) }
   before { subject.stub(notification: mock('NotificationService').as_null_object) }
   before { mr_mock.stub(:author_id) }
   before { mr_mock.stub(:target_project) }
+  before { mr_mock.stub(:source_project) }
+  before { mr_mock.stub(:project) }
+  before { mr_mock.stub(:create_cross_references!).and_return(true) }
+  before { Repository.any_instance.stub(commit: nil) }
+
   before(:each) { enable_observers }
   after(:each) { disable_observers }
 
@@ -24,11 +29,20 @@ describe MergeRequestObserver do
       subject.should_receive(:notification)
       subject.after_create(mr_mock)
     end
+
+    it 'creates cross-reference notes' do
+       project = create :project
+       mr_mock.stub(title: "this mr references !#{assigned_mr.id}", project: project)
+       mr_mock.should_receive(:create_cross_references!).with(project, some_user)
+
+       subject.after_create(mr_mock)
+    end
   end
 
   context '#after_update' do
     before(:each) do
       mr_mock.stub(:is_being_reassigned?).and_return(false)
+      mr_mock.stub(:notice_added_references)
     end
 
     it 'is called when a merge request is changed' do
@@ -41,6 +55,12 @@ describe MergeRequestObserver do
       end
     end
 
+    it 'checks for new references' do
+      mr_mock.should_receive(:notice_added_references)
+
+      subject.after_update(mr_mock)
+    end
+
     context 'a notification' do
       it 'is sent if the merge request is being reassigned' do
         mr_mock.should_receive(:is_being_reassigned?).and_return(true)
@@ -61,13 +81,13 @@ describe MergeRequestObserver do
   context '#after_close' do
     context 'a status "closed"' do
       it 'note is created if the merge request is being closed' do
-        Note.should_receive(:create_status_change_note).with(assigned_mr, assigned_mr.target_project, some_user, 'closed')
+        Note.should_receive(:create_status_change_note).with(assigned_mr, assigned_mr.target_project, some_user, 'closed', nil)
 
         assigned_mr.close
       end
 
       it 'notification is delivered only to author if the merge request is being closed' do
-        Note.should_receive(:create_status_change_note).with(unassigned_mr, unassigned_mr.target_project, some_user, 'closed')
+        Note.should_receive(:create_status_change_note).with(unassigned_mr, unassigned_mr.target_project, some_user, 'closed', nil)
 
         unassigned_mr.close
       end
@@ -77,13 +97,13 @@ describe MergeRequestObserver do
   context '#after_reopen' do
     context 'a status "reopened"' do
       it 'note is created if the merge request is being reopened' do
-        Note.should_receive(:create_status_change_note).with(closed_assigned_mr, closed_assigned_mr.target_project, some_user, 'reopened')
+        Note.should_receive(:create_status_change_note).with(closed_assigned_mr, closed_assigned_mr.target_project, some_user, 'reopened', nil)
 
         closed_assigned_mr.reopen
       end
 
       it 'notification is delivered only to author if the merge request is being reopened' do
-        Note.should_receive(:create_status_change_note).with(closed_unassigned_mr, closed_unassigned_mr.target_project, some_user, 'reopened')
+        Note.should_receive(:create_status_change_note).with(closed_unassigned_mr, closed_unassigned_mr.target_project, some_user, 'reopened', nil)
 
         closed_unassigned_mr.reopen
       end
diff --git a/spec/observers/note_observer_spec.rb b/spec/observers/note_observer_spec.rb
index 9ada92704b6..f9b96c255c1 100644
--- a/spec/observers/note_observer_spec.rb
+++ b/spec/observers/note_observer_spec.rb
@@ -5,9 +5,9 @@ describe NoteObserver do
   before { subject.stub(notification: mock('NotificationService').as_null_object) }
 
   let(:team_without_author) { (1..2).map { |n| double :user, id: n } }
+  let(:note) { double(:note).as_null_object }
 
   describe '#after_create' do
-    let(:note) { double :note }
 
     it 'is called after a note is created' do
       subject.should_receive :after_create
@@ -22,5 +22,35 @@ describe NoteObserver do
 
       subject.after_create(note)
     end
+
+    it 'creates cross-reference notes as appropriate' do
+      @p = create(:project)
+      @referenced = create(:issue, project: @p)
+      @referencer = create(:issue, project: @p)
+      @author = create(:user)
+
+      Note.should_receive(:create_cross_reference_note).with(@referenced, @referencer, @author, @p)
+
+      Note.observers.enable :note_observer do
+        create(:note, project: @p, author: @author, noteable: @referencer,
+          note: "Duplicate of ##{@referenced.iid}")
+      end
+    end
+
+    it "doesn't cross-reference system notes" do
+      Note.should_receive(:create_cross_reference_note).once
+
+      Note.observers.enable :note_observer do
+        Note.create_cross_reference_note(create(:issue), create(:issue))
+      end
+    end
+  end
+
+  describe '#after_update' do
+    it 'checks for new cross-references' do
+      note.should_receive(:notice_added_references)
+
+      subject.after_update(note)
+    end
   end
 end
diff --git a/spec/services/git_push_service_spec.rb b/spec/services/git_push_service_spec.rb
index 286a8cdaa22..ffd80f33fc8 100644
--- a/spec/services/git_push_service_spec.rb
+++ b/spec/services/git_push_service_spec.rb
@@ -6,6 +6,7 @@ describe GitPushService do
   let (:service) { GitPushService.new }
 
   before do
+    @blankrev = '0000000000000000000000000000000000000000'
     @oldrev = 'b98a310def241a6fd9c9a9a3e7934c48e498fe81'
     @newrev = 'b19a04f53caeebf4fe5ec2327cb83e9253dc91bb'
     @ref = 'refs/heads/master'
@@ -98,7 +99,7 @@ describe GitPushService do
 
       it "when pushing a branch for the first time" do
         @project_hook.should_not_receive(:execute)
-        service.execute(project, user, '00000000000000000000000000000000', 'newrev', 'refs/heads/master')
+        service.execute(project, user, @blankrev, 'newrev', 'refs/heads/master')
       end
 
       it "when pushing tags" do
@@ -107,5 +108,107 @@ describe GitPushService do
       end
     end
   end
+
+  describe "cross-reference notes" do
+    let(:issue) { create :issue, project: project }
+    let(:commit_author) { create :user }
+    let(:commit) { project.repository.commit }
+
+    before do
+      commit.stub({
+        safe_message: "this commit \n mentions ##{issue.id}",
+        references: [issue],
+        author_name: commit_author.name,
+        author_email: commit_author.email
+      })
+      project.repository.stub(commits_between: [commit])
+    end
+
+    it "creates a note if a pushed commit mentions an issue" do
+      Note.should_receive(:create_cross_reference_note).with(issue, commit, commit_author, project)
+
+      service.execute(project, user, @oldrev, @newrev, @ref)
+    end
+
+    it "only creates a cross-reference note if one doesn't already exist" do
+      Note.create_cross_reference_note(issue, commit, user, project)
+
+      Note.should_not_receive(:create_cross_reference_note).with(issue, commit, commit_author, project)
+
+      service.execute(project, user, @oldrev, @newrev, @ref)
+    end
+
+    it "defaults to the pushing user if the commit's author is not known" do
+      commit.stub(author_name: 'unknown name', author_email: 'unknown@email.com')
+      Note.should_receive(:create_cross_reference_note).with(issue, commit, user, project)
+
+      service.execute(project, user, @oldrev, @newrev, @ref)
+    end
+
+    it "finds references in the first push to a non-default branch" do
+      project.repository.stub(:commits_between).with(@blankrev, @newrev).and_return([])
+      project.repository.stub(:commits_between).with("master", @newrev).and_return([commit])
+
+      Note.should_receive(:create_cross_reference_note).with(issue, commit, commit_author, project)
+
+      service.execute(project, user, @blankrev, @newrev, 'refs/heads/other')
+    end
+
+    it "finds references in the first push to a default branch" do
+      project.repository.stub(:commits_between).with(@blankrev, @newrev).and_return([])
+      project.repository.stub(:commits).with(@newrev).and_return([commit])
+
+      Note.should_receive(:create_cross_reference_note).with(issue, commit, commit_author, project)
+
+      service.execute(project, user, @blankrev, @newrev, 'refs/heads/master')
+    end
+  end
+
+  describe "closing issues from pushed commits" do
+    let(:issue) { create :issue, project: project }
+    let(:other_issue) { create :issue, project: project }
+    let(:commit_author) { create :user }
+    let(:closing_commit) { project.repository.commit }
+
+    before do
+      closing_commit.stub({
+        issue_closing_regex: /^([Cc]loses|[Ff]ixes) #\d+/,
+        safe_message: "this is some work.\n\ncloses ##{issue.iid}",
+        author_name: commit_author.name,
+        author_email: commit_author.email
+      })
+
+      project.repository.stub(commits_between: [closing_commit])
+    end
+
+    it "closes issues with commit messages" do
+      service.execute(project, user, @oldrev, @newrev, @ref)
+
+      Issue.find(issue.id).should be_closed
+    end
+
+    it "passes the closing commit as a thread-local" do
+      service.execute(project, user, @oldrev, @newrev, @ref)
+
+      Thread.current[:current_commit].should == closing_commit
+    end
+
+    it "doesn't create cross-reference notes for a closing reference" do
+      expect {
+        service.execute(project, user, @oldrev, @newrev, @ref)
+      }.not_to change { Note.where(project_id: project.id, system: true).count }
+    end
+
+    it "doesn't close issues when pushed to non-default branches" do
+      project.stub(default_branch: 'durf')
+
+      # The push still shouldn't create cross-reference notes.
+      expect {
+        service.execute(project, user, @oldrev, @newrev, 'refs/heads/hurf')
+      }.not_to change { Note.where(project_id: project.id, system: true).count }
+
+      Issue.find(issue.id).should be_opened
+    end
+  end
 end
 
diff --git a/spec/support/login_helpers.rb b/spec/support/login_helpers.rb
index 46794f48384..025534a900d 100644
--- a/spec/support/login_helpers.rb
+++ b/spec/support/login_helpers.rb
@@ -18,6 +18,7 @@ module LoginHelpers
     fill_in "user_login", with: user.email
     fill_in "user_password", with: "123456"
     click_button "Sign in"
+    Thread.current[:current_user] = user
   end
 
   def logout
diff --git a/spec/support/mentionable_shared_examples.rb b/spec/support/mentionable_shared_examples.rb
new file mode 100644
index 00000000000..a7f189777c8
--- /dev/null
+++ b/spec/support/mentionable_shared_examples.rb
@@ -0,0 +1,94 @@
+# Specifications for behavior common to all Mentionable implementations.
+# Requires a shared context containing:
+# - let(:subject) { "the mentionable implementation" }
+# - let(:backref_text) { "the way that +subject+ should refer to itself in backreferences " }
+# - let(:set_mentionable_text) { lambda { |txt| "block that assigns txt to the subject's mentionable_text" } }
+
+def common_mentionable_setup
+  # Avoid name collisions with let(:project) or let(:author) in the surrounding scope.
+  let(:mproject) { create :project }
+  let(:mauthor) { subject.author }
+
+  let(:mentioned_issue) { create :issue, project: mproject }
+  let(:other_issue) { create :issue, project: mproject }
+  let(:mentioned_mr) { create :merge_request, target_project: mproject, source_branch: 'different' }
+  let(:mentioned_commit) { mock('commit', sha: '1234567890abcdef').as_null_object }
+
+  # Override to add known commits to the repository stub.
+  let(:extra_commits) { [] }
+
+  # A string that mentions each of the +mentioned_.*+ objects above. Mentionables should add a self-reference
+  # to this string and place it in their +mentionable_text+.
+  let(:ref_string) do
+    "mentions ##{mentioned_issue.iid} twice ##{mentioned_issue.iid}, !#{mentioned_mr.iid}, " +
+    "#{mentioned_commit.sha[0..5]} and itself as #{backref_text}"
+  end
+
+  before do
+    # Wire the project's repository to return the mentioned commit, and +nil+ for any
+    # unrecognized commits.
+    commitmap = { '123456' => mentioned_commit }
+    extra_commits.each { |c| commitmap[c.sha[0..5]] = c }
+
+    repo = mock('repository')
+    repo.stub(:commit) { |sha| commitmap[sha] }
+    mproject.stub(repository: repo)
+
+    set_mentionable_text.call(ref_string)
+  end
+end
+
+shared_examples 'a mentionable' do
+  common_mentionable_setup
+
+  it 'generates a descriptive back-reference' do
+    subject.gfm_reference.should == backref_text
+  end
+
+  it "extracts references from its reference property" do
+    # De-duplicate and omit itself
+    refs = subject.references(mproject)
+
+    refs.should have(3).items
+    refs.should include(mentioned_issue)
+    refs.should include(mentioned_mr)
+    refs.should include(mentioned_commit)
+  end
+
+  it 'creates cross-reference notes' do
+    [mentioned_issue, mentioned_mr, mentioned_commit].each do |referenced|
+      Note.should_receive(:create_cross_reference_note).with(referenced, subject.local_reference, mauthor, mproject)
+    end
+
+    subject.create_cross_references!(mproject, mauthor)
+  end
+
+  it 'detects existing cross-references' do
+    Note.create_cross_reference_note(mentioned_issue, subject.local_reference, mauthor, mproject)
+
+    subject.has_mentioned?(mentioned_issue).should be_true
+    subject.has_mentioned?(mentioned_mr).should be_false
+  end
+end
+
+shared_examples 'an editable mentionable' do
+  common_mentionable_setup
+
+  it_behaves_like 'a mentionable'
+
+  it 'creates new cross-reference notes when the mentionable text is edited' do
+    new_text = "this text still mentions ##{mentioned_issue.iid} and #{mentioned_commit.sha[0..5]}, " +
+      "but now it mentions ##{other_issue.iid}, too."
+
+    [mentioned_issue, mentioned_commit].each do |oldref|
+      Note.should_not_receive(:create_cross_reference_note).with(oldref, subject.local_reference,
+        mauthor, mproject)
+    end
+
+    Note.should_receive(:create_cross_reference_note).with(other_issue, subject.local_reference, mauthor, mproject)
+
+    subject.save
+    set_mentionable_text.call(new_text)
+    subject.notice_added_references(mproject, mauthor)
+  end
+end