Auto-highlight conflict when rich_text is called

lib/gitlab/conflict/file.rb

@@ -21,7 +21,8 @@ module Gitlab
       def lines
         @lines ||= Gitlab::Conflict::Parser.new.parse(merge_file_result[:data],
                                                       our_path: our_path,
-                                                      their_path: their_path)
+                                                      their_path: their_path,
+                                                      parent: self)
       end
 
       def resolve!(resolution, index:, rugged:)
@@ -57,27 +58,23 @@ module Gitlab
         end.compact
       end
 
-      def highlighted_lines
-        return @highlighted_lines if @highlighted_lines
-
+      def highlight_lines!
         their_highlight = Gitlab::Highlight.highlight_lines(repository, their_ref, their_path)
         our_highlight = Gitlab::Highlight.highlight_lines(repository, our_ref, our_path)
 
-        @highlighted_lines = lines.map do |line|
-          line = line.dup
+        lines.each do |line|
           if line.type == 'old'
             line.rich_text = their_highlight[line.old_line - 1]
           else
             line.rich_text = our_highlight[line.new_line - 1]
           end
-          line
         end
       end
 
       def sections
         return @sections if @sections
 
-        chunked_lines = highlighted_lines.chunk { |line| line.type.nil? }
+        chunked_lines = lines.chunk { |line| line.type.nil? }
         match_line = nil
 
         @sections = chunked_lines.flat_map.with_index do |(no_conflict, lines), i|

lib/gitlab/conflict/parser.rb

@@ -7,7 +7,7 @@ module Gitlab
       class MissingEndDelimiter < StandardError
       end
 
-      def parse(text, our_path:, their_path:)
+      def parse(text, our_path:, their_path:, parent: nil)
         return [] if text.blank?
 
         line_obj_index = 0
@@ -36,9 +36,9 @@ module Gitlab
             type = nil
           elsif line[0] == '\\'
             type = 'nonewline'
-            lines << Gitlab::Diff::Line.new(full_line, type, line_obj_index, line_old, line_new)
+            lines << Gitlab::Diff::Line.new(full_line, type, line_obj_index, line_old, line_new, parent: parent)
           else
-            lines << Gitlab::Diff::Line.new(full_line, type, line_obj_index, line_old, line_new)
+            lines << Gitlab::Diff::Line.new(full_line, type, line_obj_index, line_old, line_new, parent: parent)
             line_old += 1 if type != 'new'
             line_new += 1 if type != 'old'
 

lib/gitlab/diff/line.rb

@@ -2,12 +2,13 @@ module Gitlab
   module Diff
     class Line
       attr_reader :type, :index, :old_pos, :new_pos
+      attr_writer :rich_text
       attr_accessor :text
-      attr_accessor :rich_text
 
-      def initialize(text, type, index, old_pos, new_pos)
+      def initialize(text, type, index, old_pos, new_pos, parent: nil)
         @text, @type, @index = text, type, index
         @old_pos, @new_pos = old_pos, new_pos
+        @parent = parent
       end
 
       def self.init_from_hash(hash)
@@ -44,6 +45,12 @@ module Gitlab
         type == 'old'
       end
 
+      def rich_text
+        @parent.highlight_lines! if @parent && !@rich_text
+
+        @rich_text
+      end
+
       def meta?
         type == 'match' || type == 'nonewline'
       end

spec/lib/gitlab/conflict/file_spec.rb

@@ -63,17 +63,23 @@ describe Gitlab::Conflict::File, lib: true do
     end
   end
 
-  describe '#highlighted_lines' do
+  describe '#highlight_lines!' do
     def html_to_text(html)
       CGI.unescapeHTML(ActionView::Base.full_sanitizer.sanitize(html)).delete("\n")
     end
 
-    it 'returns lines with rich_text' do
-      expect(conflict_file.highlighted_lines).to all(have_attributes(rich_text: a_kind_of(String)))
+    it 'modifies the existing lines' do
+      expect { conflict_file.highlight_lines! }.to change { conflict_file.lines.map(&:instance_variables) }
     end
 
-    it 'returns lines with rich_text matching the text content of the line' do
-      conflict_file.highlighted_lines.each do |line|
+    it 'is called implicitly when rich_text is accessed on a line' do
+      expect(conflict_file).to receive(:highlight_lines!).once.and_call_original
+
+      conflict_file.lines.each(&:rich_text)
+    end
+
+    it 'sets the rich_text of the lines matching the text content' do
+      conflict_file.lines.each do |line|
         expect(line.text).to eq(html_to_text(line.rich_text))
       end
     end