Merge branch 'fix-underscore-notes' into 'master'

Fix cross-references that contain underscores

### What does this MR do?

Cross-references that contain underscores confuse the Markdown renderer and don't work properly. For example:

1. In  `myacct/project_one#456`, add a comment that includes a reference to `myacct/project_two#123`.
2. The comment in `myacct/project_one#456` links correctly.
3. The system note in `myacct/project_two#123` is incorrectly linked as:

`mentioned in issue myacct/projectone#456_`

This MR removes the use of the `_` character in the system notes to prevent Markdown confusion.

See a full discussion in #1160.

### Are there points in the code the reviewer needs to double check?

To preserve backwards compatibility with existing system notes, there is a SQL wildcard match for notes having underscores. This seemed safer than migrating all notes.

### Why was this MR needed?

In an ideal world, the Markdown parser would be able to handle references containing underscores with or without escape sequences. However, there are a number of issues:

1. RedCarpet's parser for emphasis block is pretty dumb: it treats `#` as a word break and thus even the `intra_word_emphasis` flag has no effect.
2. The parser is in C and can't be changed easily.
3. There is no way to insert an escape sequence for emphasis blocks.

The only way around this is to switch to something like CommonMark, which does support escape sequences.

### What are the relevant issue numbers / [Feature requests](http://feedback.gitlab.com/)?

Issue #1160

### Screenshots

Before:

![Screen_Shot_2015-03-19_at_1.39.29_AM](https://gitlab.com/gitlab-org/gitlab-ce/uploads/a1db4b96c0df2f10d9855ed5abe976ca/Screen_Shot_2015-03-19_at_1.39.29_AM.png)

After:

![Screen_Shot_2015-03-19_at_1.39.35_AM](https://gitlab.com/gitlab-org/gitlab-ce/uploads/189a062c2d19645eec1782ac1f0d4f2f/Screen_Shot_2015-03-19_at_1.39.35_AM.png)

See merge request !385

7 files changed, 175 insertions, 24 deletions

diff --git a/CHANGELOG b/CHANGELOG
index 1e256156745..fd902c6838d 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -2,6 +2,7 @@ Please view this file on the master branch, on stable branches it's out of date.
 
 v 7.10.0 (unreleased)
   - Update poltergeist to version 1.6.0 to support PhantomJS 2.0 (Zeger-Jan van de Weg)
+  - Fix cross references when usernames, milestones, or project names contain underscores (Stan Hu)
   - enable line wrapping per default and remove the checkbox to toggle it (Hannes Rosenögger)
   - extend the commit calendar to show the actual commits made on a date (Hannes Rosenögger)
   - Add a service to support external wikis (Hannes Rosenögger)
diff --git a/app/models/note.rb b/app/models/note.rb
index 649e9b4e852..27b583a869a 100644
--- a/app/models/note.rb
+++ b/app/models/note.rb
@@ -59,7 +59,7 @@ class Note < ActiveRecord::Base
 
   class << self
     def create_status_change_note(noteable, project, author, status, source)
-      body = "_Status changed to #{status}#{' by ' + source.gfm_reference if source}_"
+      body = "Status changed to #{status}#{' by ' + source.gfm_reference if source}"
 
       create(
         noteable: noteable,
@@ -95,9 +95,9 @@ class Note < ActiveRecord::Base
 
     def create_milestone_change_note(noteable, project, author, milestone)
       body = if milestone.nil?
-               '_Milestone removed_'
+               'Milestone removed'
              else
-               "_Milestone changed to #{milestone.title}_"
+               "Milestone changed to #{milestone.title}"
              end
 
       create(
@@ -110,7 +110,7 @@ class Note < ActiveRecord::Base
     end
 
     def create_assignee_change_note(noteable, project, author, assignee)
-      body = assignee.nil? ? '_Assignee removed_' : "_Reassigned to @#{assignee.username}_"
+      body = assignee.nil? ? 'Assignee removed' : "Reassigned to @#{assignee.username}"
 
       create({
         noteable: noteable,
@@ -140,7 +140,7 @@ class Note < ActiveRecord::Base
       end
 
       message << ' ' << 'label'.pluralize(labels_count)
-      body = "_#{message.capitalize}_"
+      body = "#{message.capitalize}"
 
       create(
         noteable: noteable,
@@ -170,14 +170,14 @@ class Note < ActiveRecord::Base
 
         commits_text = ActionController::Base.helpers.pluralize(existing_commits.length, 'commit')
 
-        branch = 
+        branch =
           if merge_request.for_fork?
             "#{merge_request.target_project_namespace}:#{merge_request.target_branch}"
           else
             merge_request.target_branch
           end
 
-        message = "* #{commit_ids} - _#{commits_text} from branch `#{branch}`_"
+        message = "* #{commit_ids} - #{commits_text} from branch `#{branch}`"
         body << message
         body << "\n"
       end
@@ -240,7 +240,7 @@ class Note < ActiveRecord::Base
                 where(noteable_id: noteable.id)
               end
 
-      notes.where('note like ?', cross_reference_note_content(gfm_reference)).
+      notes.where('note like ?', cross_reference_note_pattern(gfm_reference)).
         system.any?
     end
 
@@ -249,13 +249,18 @@ class Note < ActiveRecord::Base
     end
 
     def cross_reference_note_prefix
-      '_mentioned in '
+      'mentioned in '
     end
 
     private
 
     def cross_reference_note_content(gfm_reference)
-      cross_reference_note_prefix + "#{gfm_reference}_"
+      cross_reference_note_prefix + "#{gfm_reference}"
+    end
+
+    def cross_reference_note_pattern(gfm_reference)
+      # Older cross reference notes contained underscores for emphasis
+      "%" + cross_reference_note_content(gfm_reference) + "%"
     end
 
     # Prepend the mentioner's namespaced project path to the GFM reference for
diff --git a/app/services/notification_service.rb b/app/services/notification_service.rb
index 848ed77ebf8..cc5853144c5 100644
--- a/app/services/notification_service.rb
+++ b/app/services/notification_service.rb
@@ -120,7 +120,7 @@ class NotificationService
     return true unless note.noteable_type.present?
 
     # ignore gitlab service messages
-    return true if note.note.start_with?('_Status changed to closed_')
+    return true if note.note.start_with?('Status changed to closed')
     return true if note.cross_reference? && note.system == true
 
     opts = { noteable_type: note.noteable_type, project_id: note.project_id }
diff --git a/doc/api/merge_requests.md b/doc/api/merge_requests.md
index 1f3fd26a241..6a272539e45 100644
--- a/doc/api/merge_requests.md
+++ b/doc/api/merge_requests.md
@@ -375,7 +375,7 @@ Parameters:
     }
   },
   {
-    "note": "_Status changed to closed_",
+    "note": "Status changed to closed",
     "author": {
       "id": 11,
       "username": "admin",
diff --git a/doc/api/notes.md b/doc/api/notes.md
index c22e493562a..ee2f9fa0eac 100644
--- a/doc/api/notes.md
+++ b/doc/api/notes.md
@@ -21,7 +21,7 @@ Parameters:
 [
   {
     "id": 302,
-    "body": "_Status changed to closed_",
+    "body": "Status changed to closed",
     "attachment": null,
     "author": {
       "id": 1,
diff --git a/spec/lib/gitlab/reference_extractor_spec.rb b/spec/lib/gitlab/reference_extractor_spec.rb
index 034f8ee7c45..5ebe44f6fb7 100644
--- a/spec/lib/gitlab/reference_extractor_spec.rb
+++ b/spec/lib/gitlab/reference_extractor_spec.rb
@@ -120,4 +120,18 @@ describe Gitlab::ReferenceExtractor do
       expect(extracted[0][1].message).to eq(commit.message)
     end
   end
+
+  context 'with a project with an underscore' do
+    let(:project) { create(:project, path: 'test_project') }
+    let(:issue) { create(:issue, project: project) }
+
+    it 'handles project issue references' do
+      subject.analyze("this refers issue #{project.path_with_namespace}##{issue.iid}",
+          project)
+      extracted = subject.issues_for(project)
+      expect(extracted.size).to eq(1)
+      expect(extracted).to eq([issue])
+    end
+
+  end
 end
diff --git a/spec/models/note_spec.rb b/spec/models/note_spec.rb
index 17cb439c90e..a7bf5081d5b 100644
--- a/spec/models/note_spec.rb
+++ b/spec/models/note_spec.rb
@@ -182,14 +182,14 @@ describe Note do
 
     describe '#note' do
       subject { super().note }
-      it { is_expected.to match(/Status changed to #{status}/) }
+      it { is_expected.to eq("Status changed to #{status}") }
     end
 
     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)
 
-      expect(n.note).to match(/Status changed to #{status} by commit 123456/)
+      expect(n.note).to eq("Status changed to #{status} by commit 123456")
     end
   end
 
@@ -197,7 +197,7 @@ describe Note do
     let(:project) { create(:project) }
     let(:thing) { create(:issue, project: project) }
     let(:author) { create(:user) }
-    let(:assignee) { create(:user) }
+    let(:assignee) { create(:user, username: "assigned_user") }
 
     subject { Note.create_assignee_change_note(thing, project, author, assignee) }
 
@@ -227,7 +227,7 @@ describe Note do
 
     describe '#note' do
       subject { super().note }
-      it { is_expected.to match(/Reassigned to @#{assignee.username}/) }
+      it { is_expected.to eq('Reassigned to @assigned_user') }
     end
 
     context 'assignee is removed' do
@@ -235,11 +235,95 @@ describe Note do
 
       describe '#note' do
         subject { super().note }
-        it { is_expected.to match(/Assignee removed/) }
+        it { is_expected.to eq('Assignee removed') }
       end
     end
   end
 
+  describe '#create_labels_change_note' do
+    let(:project) { create(:project) }
+    let(:thing) { create(:issue, project: project) }
+    let(:author) { create(:user) }
+    let(:label1) { create(:label) }
+    let(:label2) { create(:label) }
+    let(:added_labels) { [label1, label2] }
+    let(:removed_labels) { [] }
+
+    subject { Note.create_labels_change_note(thing, project, author, added_labels, removed_labels) }
+
+    context 'creates and saves a Note' do
+      it { is_expected.to be_a Note }
+
+      describe '#id' do
+        subject { super().id }
+        it { is_expected.not_to be_nil }
+      end
+    end
+
+    describe '#noteable' do
+      subject { super().noteable }
+      it { is_expected.to eq(thing) }
+    end
+
+    describe '#project' do
+      subject { super().project }
+      it { is_expected.to eq(thing.project) }
+    end
+
+    describe '#author' do
+      subject { super().author }
+      it { is_expected.to eq(author) }
+    end
+
+    describe '#note' do
+      subject { super().note }
+      it { is_expected.to eq("Added ~#{label1.id} ~#{label2.id} labels") }
+    end
+
+    context 'label is removed' do
+      let(:added_labels) { [label1]  }
+      let(:removed_labels) { [label2] }
+
+      describe '#note' do
+        subject { super().note }
+        it { is_expected.to eq("Added ~#{label1.id} and removed ~#{label2.id} labels") }
+      end
+    end
+  end
+
+  describe '#create_milestone_change_note' do
+    let(:project) { create(:project) }
+    let(:thing) { create(:issue, project: project) }
+    let(:milestone) { create(:milestone, project: project, title: "first_milestone") }
+    let(:author) { create(:user) }
+
+    subject { Note.create_milestone_change_note(thing, project, author, milestone) }
+
+    context 'creates and saves a Note' do
+      it { is_expected.to be_a Note }
+
+      describe '#id' do
+        subject { super().id }
+        it { is_expected.not_to be_nil }
+      end
+    end
+
+    describe '#project' do
+      subject { super().project }
+      it { is_expected.to eq(thing.project) }
+    end
+
+    describe '#author' do
+      subject { super().author }
+      it { is_expected.to eq(author) }
+    end
+
+    describe '#note' do
+      subject { super().note }
+      it { is_expected.to eq("Milestone changed to first_milestone") }
+    end
+  end
+
   describe '#create_cross_reference_note' do
     let(:project)    { create(:project) }
     let(:author)     { create(:user) }
@@ -272,7 +356,7 @@ describe Note do
 
       describe '#note' do
         subject { super().note }
-        it { is_expected.to eq("_mentioned in merge request !#{mergereq.iid}_") }
+        it { is_expected.to eq("mentioned in merge request !#{mergereq.iid}") }
       end
     end
 
@@ -288,7 +372,7 @@ describe Note do
 
       describe '#note' do
         subject { super().note }
-        it { is_expected.to eq("_mentioned in commit #{commit.sha}_") }
+        it { is_expected.to eq("mentioned in commit #{commit.sha}") }
       end
     end
 
@@ -309,7 +393,7 @@ describe Note do
 
       describe '#note' do
         subject { super().note }
-        it { is_expected.to eq("_mentioned in issue ##{issue.iid}_") }
+        it { is_expected.to eq("mentioned in issue ##{issue.iid}") }
       end
     end
 
@@ -330,7 +414,7 @@ describe Note do
 
       describe '#note' do
         subject { super().note }
-        it { is_expected.to eq("_mentioned in merge request !#{mergereq.iid}_") }
+        it { is_expected.to eq("mentioned in merge request !#{mergereq.iid}") }
       end
     end
 
@@ -362,7 +446,7 @@ describe Note do
 
       describe '#note' do
         subject { super().note }
-        it { is_expected.to eq("_mentioned in issue ##{issue.iid}_") }
+        it { is_expected.to eq("mentioned in issue ##{issue.iid}") }
       end
     end
 
@@ -389,7 +473,7 @@ describe Note do
 
       describe '#note' do
         subject { super().note }
-        it { is_expected.to eq("_mentioned in commit #{parent_commit.id}_") }
+        it { is_expected.to eq("mentioned in commit #{parent_commit.id}") }
       end
     end
   end
@@ -421,6 +505,41 @@ describe Note do
       it { expect(Note.cross_reference_exists?(commit0, commit1)).to be_truthy }
       it { expect(Note.cross_reference_exists?(commit1, commit0)).to be_falsey }
     end
+
+    context 'legacy note with Markdown emphasis' do
+      let(:issue2) { create :issue, project: project }
+      let!(:note) do
+        create :note, system: true, noteable_id: issue2.id,
+                      noteable_type: "Issue", note: "_mentioned in issue " \
+                      "#{issue.project.path_with_namespace}##{issue.iid}_"
+      end
+
+      it 'detects if a mentionable with emphasis has been mentioned' do
+        expect(Note.cross_reference_exists?(issue2, issue)).to be_truthy
+      end
+    end
+  end
+
+  describe '#cross_references_with_underscores?' do
+    let(:project) { create :project, path: "first_project" }
+    let(:second_project) { create :project, path: "second_project" }
+
+    let(:author) { create :user }
+    let(:issue0) { create :issue, project: project }
+    let(:issue1) { create :issue, project: second_project }
+    let!(:note) { Note.create_cross_reference_note(issue0, issue1, author, project) }
+
+    it 'detects if a mentionable has already been mentioned' do
+      expect(Note.cross_reference_exists?(issue0, issue1)).to be_truthy
+    end
+
+    it 'detects if a mentionable has not already been mentioned' do
+      expect(Note.cross_reference_exists?(issue1, issue0)).to be_falsey
+    end
+
+    it 'detects that text has underscores' do
+      expect(note.note).to eq("mentioned in issue #{second_project.path_with_namespace}##{issue1.iid}")
+    end
   end
 
   describe '#system?' do
@@ -429,6 +548,8 @@ describe Note do
     let(:other)   { create(:issue, project: project) }
     let(:author)  { create(:user) }
     let(:assignee) { create(:user) }
+    let(:label) { create(:label) }
+    let(:milestone) { create(:milestone) }
 
     it 'should recognize user-supplied notes as non-system' do
       @note = create(:note_on_issue)
@@ -449,6 +570,16 @@ describe Note do
       @note = Note.create_assignee_change_note(issue, project, author, assignee)
       expect(@note).to be_system
     end
+
+    it 'should identify label-change notes as system notes' do
+      @note = Note.create_labels_change_note(issue, project, author, [label], [])
+      expect(@note).to be_system
+    end
+
+    it 'should identify milestone-change notes as system notes' do
+      @note = Note.create_milestone_change_note(issue, project, author, milestone)
+      expect(@note).to be_system
+    end
   end
 
   describe :authorization do