Merge branch 'merge-request-deleted-file' into 'master'

Correctly find last known blob for file deleted in MR.

Fixes #3092.

When building a new MR, `@merge_request.commits.last` would fail because this delegates to `merge_request_diff` which is still `nil` at that point. I fixed that, and changed some of the logic because showing deleted blob contents didn't previously work for the Compare page, and the UI would show the wrong commit sha for "View File @...".

See merge request !1647

app/controllers/projects/compare_controller.rb

@@ -17,9 +17,10 @@ class Projects::CompareController < Projects::ApplicationController
       execute(@project, head_ref, @project, base_ref)
     if compare_result
-      @commits = compare_result.commits
+      @commits = Commit.decorate(compare_result.commits, @project)
       @diffs = compare_result.diffs
       @commit = @commits.last
+      @first_commit = @commits.first
       @line_notes = []
     end
   end

app/controllers/projects/merge_requests_controller.rb

@@ -56,6 +56,8 @@ class Projects::MergeRequestsController < Projects::ApplicationController
   def diffs
     @commit = @merge_request.last_commit
+    @first_commit = @merge_request.first_commit
+
     @comments_allowed = @reply_allowed = true
     @comments_target = {
       noteable_type: 'MergeRequest',
@@ -89,7 +91,8 @@ class Projects::MergeRequestsController < Projects::ApplicationController
     @target_project = merge_request.target_project
     @source_project = merge_request.source_project
     @commits = @merge_request.compare_commits
-    @commit = @merge_request.compare_commits.last
+    @commit = @merge_request.last_commit
+    @first_commit = @merge_request.first_commit
     @diffs = @merge_request.compare_diffs
     @note_counts = Note.where(commit_id: @commits.map(&:id)).
       group(:commit_id).count

app/helpers/diff_helper.rb

@@ -170,7 +170,8 @@ module DiffHelper
   def commit_for_diff(diff)
     if diff.deleted_file
-      @merge_request ? @merge_request.commits.last : @commit.parents.first
+      first_commit = @first_commit || @commit
+      first_commit.parent
     else
       @commit
     end

app/models/commit.rb

@@ -164,6 +164,14 @@ class Commit
     @committer ||= User.find_by_any_email(committer_email)
   end
+  def parents
+    @parents ||= parent_ids.map { |id| project.commit(id) }
+  end
+
+  def parent
+    @parent ||= project.commit(self.parent_id) if self.parent_id
+  end
+
   def notes
     project.notes.for_commit_id(self.id)
   end
@@ -181,10 +189,6 @@ class Commit
     @raw.short_id(7)
   end
-  def parents
-    @parents ||= Commit.decorate(super, project)
-  end
-
   def ci_commit
     project.ci_commit(sha)
   end

app/models/merge_request.rb

@@ -40,7 +40,7 @@ class MergeRequest < ActiveRecord::Base
   after_create :create_merge_request_diff
   after_update :update_merge_request_diff
-  delegate :commits, :diffs, :last_commit, :last_commit_short_sha, to: :merge_request_diff, prefix: nil
+  delegate :commits, :diffs, to: :merge_request_diff, prefix: nil
   # When this attribute is true some MR validation is ignored
   # It allows us to close or modify broken merge requests
@@ -157,6 +157,18 @@ class MergeRequest < ActiveRecord::Base
     reference
   end
+  def last_commit
+    merge_request_diff ? merge_request_diff.last_commit : compare_commits.last
+  end 
+
+  def first_commit
+    merge_request_diff ? merge_request_diff.first_commit : compare_commits.first
+  end 
+
+  def last_commit_short_sha
+    last_commit.short_id
+  end
+
   def validate_branches
     if target_project == source_project && target_branch == source_branch
       errors.add :branch_conflict, "You can not use same project/branch for source and target"

app/models/merge_request_diff.rb

@@ -55,6 +55,10 @@ class MergeRequestDiff < ActiveRecord::Base
     commits.first
   end
+  def first_commit
+    commits.last
+  end
+
   def last_commit_short_sha
     @last_commit_short_sha ||= last_commit.short_id
   end

app/models/repository.rb

@@ -312,13 +312,7 @@ class Repository
   end
   def blob_for_diff(commit, diff)
-    file = blob_at(commit.id, diff.new_path)
-
-    unless file
-      file = prev_blob_for_diff(commit, diff)
-    end
-
-    file
+    blob_at(commit.id, diff.file_path)
   end
   def prev_blob_for_diff(commit, diff)

app/views/projects/diffs/_diffs.html.haml

@@ -15,8 +15,8 @@
 .files
   - diff_files.each_with_index do |diff_file, index|
-    - diff_commit = commit_for_diff(diff_file.diff)
-    - blob = project.repository.blob_for_diff(diff_commit, diff_file.diff)
+    - diff_commit = commit_for_diff(diff_file)
+    - blob = project.repository.blob_for_diff(diff_commit, diff_file)
     - next unless blob
     = render 'projects/diffs/file', i: index, project: project,

app/views/projects/diffs/_file.html.haml

 .diff-file{id: "diff-#{i}", data: diff_file_html_data(project, diff_commit, diff_file)}
-  .diff-header{id: "file-path-#{hexdigest(diff_file.new_path || diff_file.old_path)}"}
+  .diff-header{id: "file-path-#{hexdigest(diff_file.file_path)}"}
     - if diff_file.diff.submodule?
       %span
         - submodule_item = project.repository.blob_at(@commit.id, diff_file.file_path)
@@ -38,7 +38,7 @@
       - else
         = render "projects/diffs/text_file", diff_file: diff_file, index: i
     - elsif blob.image?
-      - old_file = project.repository.prev_blob_for_diff(@commit, diff_file)
+      - old_file = project.repository.prev_blob_for_diff(diff_commit, diff_file)
       = render "projects/diffs/image", diff_file: diff_file, old_file: old_file, file: blob, index: i
     - else
       .nothing-here-block No preview for this file type