Allow callsite for merge request view

The view was generating a cross-database query. Add a specific allowlist
to this callsite so that we can shrink the spec allowlist (it is being
referenced 3,000 times in CI).

app/controllers/projects/merge_requests_controller.rb

@@ -126,6 +126,10 @@ class Projects::MergeRequestsController < Projects::MergeRequests::ApplicationCo
 
         set_pipeline_variables
 
+        ::Gitlab::Database.allow_cross_joins_across_databases(url: 'https://gitlab.com/gitlab-org/gitlab/-/issues/336891') do
+          @number_of_pipelines = @pipelines.size
+        end
+
         render
       end
 

app/views/projects/merge_requests/show.html.haml

@@ -6,7 +6,6 @@
 - page_description @merge_request.description_html
 - page_card_attributes @merge_request.card_attributes
 - suggest_changes_help_path = help_page_path('user/project/merge_requests/reviews/suggestions.md')
-- number_of_pipelines = @pipelines.size
 - mr_action = j(params[:tab].presence || 'show')
 - add_page_specific_style 'page_bundles/merge_requests'
 - add_page_specific_style 'page_bundles/pipelines'
@@ -32,11 +31,11 @@
               = tab_link_for @merge_request, :commits do
                 = _("Commits")
                 %span.badge.badge-pill.gl-badge.badge-muted.sm= @commits_count
-          - if number_of_pipelines.nonzero?
+          - if @number_of_pipelines.nonzero?
             = render "projects/merge_requests/tabs/tab", name: "pipelines", class: "pipelines-tab" do
               = tab_link_for @merge_request, :pipelines do
                 = _("Pipelines")
-                %span.badge.badge-pill.gl-badge.badge-muted.sm.js-pipelines-mr-count= number_of_pipelines
+                %span.badge.badge-pill.gl-badge.badge-muted.sm.js-pipelines-mr-count= @number_of_pipelines
           = render "projects/merge_requests/tabs/tab", name: "diffs", class: "diffs-tab", id: "diffs-tab", qa_selector: "diffs_tab" do
             = tab_link_for @merge_request, :diffs do
               = _("Changes")
@@ -76,7 +75,7 @@
       = render "projects/merge_requests/tabs/pane", name: "commits", id: "commits", class: "commits" do
         -# This tab is always loaded via AJAX
       = render "projects/merge_requests/tabs/pane", name: "pipelines", id: "pipelines", class: "pipelines" do
-        - if number_of_pipelines.nonzero?
+        - if @number_of_pipelines.nonzero?
           = render 'projects/commit/pipelines_list', disable_initialization: true, endpoint: pipelines_project_merge_request_path(@project, @merge_request)
       - params = request.query_parameters
       - if Feature.enabled?(:default_merge_ref_for_diffs, @project, default_enabled: :yaml)

spec/support/database/cross-join-allowlist.yml

@@ -183,7 +183,6 @@
 - "./spec/features/merge_request/user_sees_merge_request_pipelines_spec.rb"
 - "./spec/features/merge_request/user_sees_merge_widget_spec.rb"
 - "./spec/features/merge_request/user_sees_mini_pipeline_graph_spec.rb"
-- "./spec/features/merge_request/user_sees_mr_with_deleted_source_branch_spec.rb"
 - "./spec/features/merge_request/user_sees_notes_from_forked_project_spec.rb"
 - "./spec/features/merge_request/user_sees_pipelines_from_forked_project_spec.rb"
 - "./spec/features/merge_request/user_sees_pipelines_spec.rb"

spec/support/shared_contexts/issuable/merge_request_shared_context.rb

@@ -16,7 +16,7 @@ RSpec.shared_context 'merge request show action' do
     assign(:merge_request, merge_request)
     assign(:note, note)
     assign(:noteable, merge_request)
-    assign(:pipelines, [])
+    assign(:number_of_pipelines, 0)
     assign(:issuable_sidebar, serialize_issuable_sidebar(user, project, merge_request))
 
     preload_view_requirements(merge_request, note)