Merge remote-tracking branch 'upstream/master' into 27377-preload-pipeline-entity27377-preload-pipeline-entity

* upstream/master: (2534 commits)
  Update VERSION to 9.3.0-pre
  Update CHANGELOG.md for 9.2.0
  removes unnecessary redundacy in usage ping doc
  Respect the typo as rubocop said
  Add a test to ensure this works on MySQL
  Change pipelines schedules help page path
  change domain to hostname in usage ping doc
  Fixes broken MySQL migration for retried
  Show password field mask while editing service settings
  Add notes for supported schedulers and cloud providers
  Move environment monitoring to environments doc
  Add docs for change of Cache/Artifact restore order"
  Avoid resource intensive login checks if password is not provided
  Change translation for 'coding' by 'desarrollo' for Spanish
  Add to docs: issues multiple assignees
  rename "Add emoji" and "Award emoji" to "Add reaction" where appropriate
  Add project and group notification settings info
  32570 Fix border-bottom for project activity tab
  Add users endpoint to frontend API class
  Rename users on mysql
  ...

6 files changed, 47 insertions, 125 deletions

diff --git a/lib/gitlab/diff/diff_refs.rb b/lib/gitlab/diff/diff_refs.rb
index 8406ca4269c..7948782aecc 100644
--- a/lib/gitlab/diff/diff_refs.rb
+++ b/lib/gitlab/diff/diff_refs.rb
@@ -18,6 +18,12 @@ module Gitlab
           head_sha == other.head_sha
       end
 
+      alias_method :eql?, :==
+
+      def hash
+        [base_sha, start_sha, head_sha].hash
+      end
+
       # There is only one case in which we will have `start_sha` and `head_sha`,
       # but not `base_sha`, which is when a diff is generated between an
       # orphaned branch and another branch, which means there _is_ no base, but
diff --git a/lib/gitlab/diff/file_collection/merge_request_diff.rb b/lib/gitlab/diff/file_collection/merge_request_diff.rb
index 329d12f13d1..0bd226ef050 100644
--- a/lib/gitlab/diff/file_collection/merge_request_diff.rb
+++ b/lib/gitlab/diff/file_collection/merge_request_diff.rb
@@ -15,6 +15,10 @@ module Gitlab
           super.tap { |_| store_highlight_cache }
         end
 
+        def real_size
+          @merge_request_diff.real_size
+        end
+
         private
 
         # Extracted method to highlight in the same iteration to the diff_collection.
diff --git a/lib/gitlab/diff/inline_diff_markdown_marker.rb b/lib/gitlab/diff/inline_diff_markdown_marker.rb
new file mode 100644
index 00000000000..c2a2eb15931
--- /dev/null
+++ b/lib/gitlab/diff/inline_diff_markdown_marker.rb
@@ -0,0 +1,17 @@
+module Gitlab
+  module Diff
+    class InlineDiffMarkdownMarker < Gitlab::StringRangeMarker
+      MARKDOWN_SYMBOLS = {
+        addition: "+",
+        deletion: "-"
+      }.freeze
+
+      def mark(line_inline_diffs, mode: nil)
+        super(line_inline_diffs) do |text, left:, right:|
+          symbol = MARKDOWN_SYMBOLS[mode]
+          "{#{symbol}#{text}#{symbol}}"
+        end
+      end
+    end
+  end
+end
diff --git a/lib/gitlab/diff/inline_diff_marker.rb b/lib/gitlab/diff/inline_diff_marker.rb
index 736933b1c4b..919965100ae 100644
--- a/lib/gitlab/diff/inline_diff_marker.rb
+++ b/lib/gitlab/diff/inline_diff_marker.rb
@@ -1,137 +1,21 @@
 module Gitlab
   module Diff
-    class InlineDiffMarker
-      MARKDOWN_SYMBOLS = {
-        addition: "+",
-        deletion: "-"
-      }.freeze
-
-      attr_accessor :raw_line, :rich_line
-
-      def initialize(raw_line, rich_line = raw_line)
-        @raw_line = raw_line
-        @rich_line = ERB::Util.html_escape(rich_line)
-      end
-
-      def mark(line_inline_diffs, mode: nil, markdown: false)
-        return rich_line unless line_inline_diffs
-
-        marker_ranges = []
-        line_inline_diffs.each do |inline_diff_range|
-          # Map the inline-diff range based on the raw line to character positions in the rich line
-          inline_diff_positions = position_mapping[inline_diff_range].flatten
-          # Turn the array of character positions into ranges
-          marker_ranges.concat(collapse_ranges(inline_diff_positions))
-        end
-
-        offset = 0
-
-        # Mark each range
-        marker_ranges.each_with_index do |range, index|
-          before_content =
-            if markdown
-              "{#{MARKDOWN_SYMBOLS[mode]}"
-            else
-              "<span class='#{html_class_names(marker_ranges, mode, index)}'>"
-            end
-          after_content =
-            if markdown
-              "#{MARKDOWN_SYMBOLS[mode]}}"
-            else
-              "</span>"
-            end
-          offset = insert_around_range(rich_line, range, before_content, after_content, offset)
+    class InlineDiffMarker < Gitlab::StringRangeMarker
+      def mark(line_inline_diffs, mode: nil)
+        super(line_inline_diffs) do |text, left:, right:|
+          %{<span class="#{html_class_names(left, right, mode)}">#{text}</span>}
         end
-
-        rich_line.html_safe
       end
 
       private
 
-      def html_class_names(marker_ranges, mode, index)
+      def html_class_names(left, right, mode)
         class_names = ["idiff"]
-        class_names << "left"  if index == 0
-        class_names << "right" if index == marker_ranges.length - 1
+        class_names << "left"  if left
+        class_names << "right" if right
         class_names << mode if mode
         class_names.join(" ")
       end
-
-      # Mapping of character positions in the raw line, to the rich (highlighted) line
-      def position_mapping
-        @position_mapping ||= begin
-          mapping = []
-          rich_pos = 0
-          (0..raw_line.length).each do |raw_pos|
-            rich_char = rich_line[rich_pos]
-
-            # The raw and rich lines are the same except for HTML tags,
-            # so skip over any `<...>` segment
-            while rich_char == '<'
-              until rich_char == '>'
-                rich_pos += 1
-                rich_char = rich_line[rich_pos]
-              end
-
-              rich_pos += 1
-              rich_char = rich_line[rich_pos]
-            end
-
-            # multi-char HTML entities in the rich line correspond to a single character in the raw line
-            if rich_char == '&'
-              multichar_mapping = [rich_pos]
-              until rich_char == ';'
-                rich_pos += 1
-                multichar_mapping << rich_pos
-                rich_char = rich_line[rich_pos]
-              end
-
-              mapping[raw_pos] = multichar_mapping
-            else
-              mapping[raw_pos] = rich_pos
-            end
-
-            rich_pos += 1
-          end
-
-          mapping
-        end
-      end
-
-      # Takes an array of integers, and returns an array of ranges covering the same integers
-      def collapse_ranges(positions)
-        return [] if positions.empty?
-        ranges = []
-
-        start = prev = positions[0]
-        range = start..prev
-        positions[1..-1].each do |pos|
-          if pos == prev + 1
-            range = start..pos
-            prev = pos
-          else
-            ranges << range
-            start = prev = pos
-            range = start..prev
-          end
-        end
-        ranges << range
-
-        ranges
-      end
-
-      # Inserts tags around the characters identified by the given range
-      def insert_around_range(text, range, before, after, offset = 0)
-        # Just to be sure
-        return offset if offset + range.end + 1 > text.length
-
-        text.insert(offset + range.begin, before)
-        offset += before.length
-
-        text.insert(offset + range.end + 1, after)
-        offset += after.length
-
-        offset
-      end
     end
   end
 end
diff --git a/lib/gitlab/diff/line.rb b/lib/gitlab/diff/line.rb
index 114656958e3..0a15c6d9358 100644
--- a/lib/gitlab/diff/line.rb
+++ b/lib/gitlab/diff/line.rb
@@ -33,6 +33,10 @@ module Gitlab
         new_pos unless removed? || meta?
       end
 
+      def line
+        new_line || old_line
+      end
+
       def unchanged?
         type.nil?
       end
diff --git a/lib/gitlab/diff/position_tracer.rb b/lib/gitlab/diff/position_tracer.rb
index 4d04f867268..e89ff238ec7 100644
--- a/lib/gitlab/diff/position_tracer.rb
+++ b/lib/gitlab/diff/position_tracer.rb
@@ -16,7 +16,7 @@ module Gitlab
       end
 
       def trace(old_position)
-        return unless old_diff_refs.complete? && new_diff_refs.complete?
+        return unless old_diff_refs&.complete? && new_diff_refs&.complete?
         return unless old_position.diff_refs == old_diff_refs
 
         # Suppose we have an MR with source branch `feature` and target branch `master`.
@@ -82,7 +82,7 @@ module Gitlab
 
         file_diff, old_line, new_line = results
 
-        Position.new(
+        new_position = Position.new(
           old_path: file_diff.old_path,
           new_path: file_diff.new_path,
           head_sha: new_diff_refs.head_sha,
@@ -91,6 +91,13 @@ module Gitlab
           old_line: old_line,
           new_line: new_line
         )
+
+        # If a position is found, but is not actually contained in the diff, for example
+        # because it was an unchanged line in the context of a change that was undone,
+        # we cannot return this as a successful trace.
+        return unless new_position.diff_line(repository)
+
+        new_position
       end
 
       private