Add Linked file feature

Remove `pinned_file` feature flag

Changelog: added

- [Introduced](#387246) in GitLab 16.9 [with a flag](../../administration/feature_flags.md) named `pinned_file`. Disabled by default.
- [Enabled on GitLab.com](#433250 (comment 1751596958)) in GitLab 16.9.
- [Generally available](#433250) in GitLab 17.4. Feature flag `pinned_file` removed.

app/assets/javascripts/diffs/components/diff_row_utils.js

@@ -39,9 +39,7 @@ export const fileContentsId = (diffFile) => {
 
 const createDiffUrl = (diffFile) => {
   const url = new URL(window.location);
-  if (window?.gon?.features?.pinnedFile) {
-    url.searchParams.set('file', diffFile.file_hash);
-  }
+  url.searchParams.set('file', diffFile.file_hash);
   return url;
 };
 

app/controllers/projects/merge_requests_controller.rb

@@ -44,7 +44,6 @@ class Projects::MergeRequestsController < Projects::MergeRequests::ApplicationCo
     push_frontend_feature_flag(:mr_pipelines_graphql, project)
     push_frontend_feature_flag(:ci_graphql_pipeline_mini_graph, project)
     push_frontend_feature_flag(:notifications_todos_buttons, current_user)
-    push_frontend_feature_flag(:pinned_file, project)
     push_frontend_feature_flag(:reviewer_assign_drawer, current_user)
     push_frontend_feature_flag(:async_merge_request_pipeline_creation, current_user)
   end
@@ -458,9 +457,7 @@ def render_html_page
     @update_current_user_path = expose_path(api_v4_user_preferences_path)
     @endpoint_metadata_url = endpoint_metadata_url(@project, @merge_request)
     @endpoint_diff_batch_url = endpoint_diff_batch_url(@project, @merge_request)
-    if params[:file] && Feature.enabled?(:pinned_file, @project)
-      @linked_file_url = linked_file_url(@project, @merge_request)
-    end
+    @linked_file_url = linked_file_url(@project, @merge_request) if params[:file]
 
     if merge_request.diffs_batch_cache_with_max_age?
       @diffs_batch_cache_key = @merge_request.merge_head_diff&.patch_id_sha

config/feature_flags/development/pinned_file.yml

----
-name: pinned_file
-introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/137544
-rollout_issue_url: https://gitlab.com/gitlab-org/gitlab/-/issues/433250
-milestone: '16.9'
-type: development
-group: group::code review
-default_enabled: false

doc/user/project/merge_requests/changes.md

@@ -81,10 +81,7 @@ DETAILS:
 **Offering:** GitLab.com
 
 > - [Introduced](https://gitlab.com/gitlab-org/gitlab/-/issues/387246) in GitLab 16.9 [with a flag](../../../administration/feature_flags.md) named `pinned_file`. Disabled by default.
-
-FLAG:
-The availability of this feature is controlled by a feature flag.
-For more information, see the history.
+> - [Generally available](https://gitlab.com/gitlab-org/gitlab/-/merge_requests/162503) in GitLab 17.4. Feature flag `pinned_file` removed.
 
 When you share a merge request link with a team member, you might want to show a specific file
 first in the list of changed files. To copy a merge request link that shows your desired file first:

spec/frontend/diffs/components/diff_row_utils_spec.js

@@ -129,14 +129,6 @@ describe('diff_row_utils', () => {
     });
 
     describe('linked file enabled', () => {
-      beforeEach(() => {
-        window.gon.features = { pinnedFile: true };
-      });
-
-      afterEach(() => {
-        delete window.gon.features;
-      });
-
       it(`should return linked file URL`, () => {
         const diffFile = getDiffFileMock();
         expect(utils.lineHref({ line_code: LINE_CODE }, diffFile)).toContain(
@@ -147,37 +139,20 @@ describe('diff_row_utils', () => {
   });
 
   describe('createFileUrl', () => {
-    describe('linked file enabled', () => {
-      beforeEach(() => {
-        window.gon.features = { pinnedFile: true };
-      });
-
-      afterEach(() => {
-        delete window.gon.features;
-      });
-
-      it(`should return linked file URL`, () => {
-        const diffFile = getDiffFileMock();
-        const url = utils.createFileUrl(diffFile);
-        expect(url.searchParams.get('file')).toBe(diffFile.file_hash);
-        expect(url.hash).toBe(`#diff-content-${diffFile.file_hash}`);
-      });
-
-      it(`removes existing linked file search param`, () => {
-        const newLocation = new URL(window.location);
-        newLocation.searchParams.append('file', 'foo');
-        setWindowLocation(newLocation.toString());
-        const diffFile = getDiffFileMock();
-        const url = utils.createFileUrl(diffFile);
-        expect(url.searchParams.get('file')).toBe(diffFile.file_hash);
-        expect(url.hash).toBe(`#diff-content-${diffFile.file_hash}`);
-      });
+    it(`should return linked file URL`, () => {
+      const diffFile = getDiffFileMock();
+      const url = utils.createFileUrl(diffFile);
+      expect(url.searchParams.get('file')).toBe(diffFile.file_hash);
+      expect(url.hash).toBe(`#diff-content-${diffFile.file_hash}`);
     });
 
-    it('should return file URL', () => {
+    it(`removes existing linked file search param`, () => {
+      const newLocation = new URL(window.location);
+      newLocation.searchParams.append('file', 'foo');
+      setWindowLocation(newLocation.toString());
       const diffFile = getDiffFileMock();
       const url = utils.createFileUrl(diffFile);
-      expect(url.searchParams.get('file')).toBe(null);
+      expect(url.searchParams.get('file')).toBe(diffFile.file_hash);
       expect(url.hash).toBe(`#diff-content-${diffFile.file_hash}`);
     });
   });