Merge branch 'new-diff-notes' into 'master'

New diff notes

Fixes #12732, #14731, #19375, #14783 

Builds on https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/4110

To do:
- [x] Get it mostly working
- [x] Validate position validity
- [x] Fix: Don’t link to `#`
- [x] Fix: Base ref can be `nil`, potentially, when the MR has an oprhan source branch => Yep, doesn’t work. We need to store a `start_id`
- [x] Optimize: Fewer duplicate `git diff` compares
- [x] Optimize: Pass paths to `PositionTracer#diff` for faster diffs
- [x] Refactor: Use `head_id` in `MergeRequest`/`MergeRequestDiff` instead of `source_sha`
- [x] Refactor: Convert existing array-based diff refs to the DiffRefs model
- [x] Tweak: Use `note_type` in `Autosave` key
- [x] Tweak: Remove `line_code: note.line_code` from `link_to_reply_discussion`
- [x] Update: `SentNotifications` and reply-by-email receiver
- [x] Update: MR diff notification email
- [x] Update: API (MR, Commit note creation and entity)
- [x] Update: GitHub importer
- [x] Address any other TODO comments
- [x] Fix: Suppress "edited 4 minutes ago"
- [x] Write tests
  - [x] `LineMapper`
  - [x] `PositionTracer`
  - [x] `Position`
  - [x] `DiffPositionUpdateService`
  - [x] `DiffNote`
  - [x] `MergeRequests::RefreshService` / `MergeRequest#update_diff_notes_positions`
- [x] Make sure commits with diff notes don't get cleaned up, since this would prevent the diff notes from being rendered (https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/5062)

Future improvements:
- Display unresolved comments on files outside the diff, if the comment was added when that file _was_ part of the diff
- Allow commenting on sections between hunks, when expanding the diff using `...`
  - (We'd need to generate line code based on Position if we have it, even if it falls outside bounds of diff)
- `diff_hunk` on diff note API entity
- Show diff hunk in notification email
- Resolved line notes would have a boolean, and be inactive through `notes.any? { !active? || resolved? }`
- Multi line notes would store a number of positions, and do the right thing (™) in grouping and then rendering if the first item is multiline? => true
- Image diff notes could store x,y,width,height instead of old_line,new_line for similar grouping. Does it need a reference to say if it's on old or new? These can't have line_codes, clearly. Rendering would be interesting.
- Show commit line comments in the MR diff
- Comment on specific selected words
- Comment on file header
- Unfold top of discussion diff note
- New diff notes API for commits and MRs

/cc @rspeicher

See merge request !4101

1 files changed, 29 insertions, 4 deletions

diff --git a/spec/factories/notes.rb b/spec/factories/notes.rb
index 696cf276e57..83e38095feb 100644
--- a/spec/factories/notes.rb
+++ b/spec/factories/notes.rb
@@ -10,21 +10,46 @@ FactoryGirl.define do
     on_issue
 
     factory :note_on_commit,             traits: [:on_commit]
-    factory :note_on_commit_diff,        traits: [:on_commit, :on_diff], class: LegacyDiffNote
     factory :note_on_issue,              traits: [:on_issue], aliases: [:votable_note]
     factory :note_on_merge_request,      traits: [:on_merge_request]
-    factory :note_on_merge_request_diff, traits: [:on_merge_request, :on_diff], class: LegacyDiffNote
     factory :note_on_project_snippet,    traits: [:on_project_snippet]
     factory :system_note,                traits: [:system]
 
+    factory :legacy_diff_note_on_commit, traits: [:on_commit, :legacy_diff_note], class: LegacyDiffNote
+    factory :legacy_diff_note_on_merge_request, traits: [:on_merge_request, :legacy_diff_note], class: LegacyDiffNote
+
+    factory :diff_note_on_merge_request, traits: [:on_merge_request], class: DiffNote do
+      position do
+        Gitlab::Diff::Position.new(
+          old_path: "files/ruby/popen.rb",
+          new_path: "files/ruby/popen.rb",
+          old_line: nil,
+          new_line: 14,
+          diff_refs: noteable.diff_refs
+        )
+      end
+    end
+
+    factory :diff_note_on_commit, traits: [:on_commit], class: DiffNote do
+      position do
+        Gitlab::Diff::Position.new(
+          old_path: "files/ruby/popen.rb",
+          new_path: "files/ruby/popen.rb",
+          old_line: nil,
+          new_line: 14,
+          diff_refs: project.commit(commit_id).try(:diff_refs)
+        )
+      end
+    end
+
     trait :on_commit do
       noteable nil
-      noteable_id nil
       noteable_type 'Commit'
+      noteable_id nil
       commit_id RepoHelpers.sample_commit.id
     end
 
-    trait :on_diff do
+    trait :legacy_diff_note do
       line_code "0_184_184"
     end