Remove expand diff to full file feature flag

app/assets/javascripts/diffs/components/diff_file_header.vue

@@ -128,9 +128,6 @@ export default {
     isModeChanged() {
       return this.diffFile.viewer.name === diffViewerModes.mode_changed;
     },
-    showExpandDiffToFullFileEnabled() {
-      return gon.features.expandDiffFullFile && !this.diffFile.is_fully_expanded;
-    },
   },
   mounted() {
     polyfillSticky(this.$refs.header);
@@ -258,7 +255,7 @@ export default {
         <icon name="external-link" />
       </gl-button>
       <gl-button
-        v-if="showExpandDiffToFullFileEnabled"
+        v-if="!diffFile.is_fully_expanded"
         class="expand-file js-expand-file"
         @click="toggleFullDiff(diffFile.file_path)"
       >

app/controllers/projects/merge_requests_controller.rb

@@ -16,10 +16,6 @@ class Projects::MergeRequestsController < Projects::MergeRequests::ApplicationCo
   before_action :authenticate_user!, only: [:assign_related_issues]
   before_action :check_user_can_push_to_source_branch!, only: [:rebase]
-  before_action only: [:show] do
-    push_frontend_feature_flag(:expand_diff_full_file)
-  end
-
   def index
     @merge_requests = @issuables

app/serializers/diff_file_entity.rb

@@ -57,7 +57,7 @@ class DiffFileEntity < DiffFileBaseEntity
     diff_file.diff_lines_for_serializer
   end
-  expose :is_fully_expanded, if: -> (diff_file, _) { Feature.enabled?(:expand_diff_full_file, default_enabled: true) && diff_file.text? } do |diff_file|
+  expose :is_fully_expanded, if: -> (diff_file, _) { diff_file.text? } do |diff_file|
     diff_file.fully_expanded?
   end

spec/javascripts/diffs/components/diff_file_header_spec.js

@@ -23,9 +23,6 @@ describe('diff_file_header', () => {
   });
   beforeEach(() => {
-    gon.features = {
-      expandDiffFullFile: true,
-    };
     const diffFile = diffDiscussionMock.diff_file;
     diffFile.added_lines = 2;