Merge branch 'fix-activerecord-join-stupidity' into 'master'

Ignore eager loading in Project.search UNION

This fixes issues such as filtering groups by names on pages such as
https://gitlab.com/dashboard/groups.

See merge request !3229

app/models/project.rb

@@ -286,7 +286,14 @@ class Project < ActiveRecord::Base
           or(ptable[:description].matches(pattern))
       )
 
+      # We explicitly remove any eager loading clauses as they're:
+      #
+      # 1. Not needed by this query
+      # 2. Combined with .joins(:namespace) lead to all columns from the
+      #    projects & namespaces tables being selected, leading to a SQL error
+      #    due to the columns of all UNION'd queries no longer being the same.
       namespaces = select(:id).
+        except(:includes).
         joins(:namespace).
         where(ntable[:name].matches(pattern))
 

spec/models/project_spec.rb

@@ -634,6 +634,12 @@ describe Project, models: true do
     it 'returns projects with a matching namespace name regardless of the casing' do
       expect(described_class.search(project.namespace.name.upcase)).to eq([project])
     end
+
+    it 'returns projects when eager loading namespaces' do
+      relation = described_class.all.includes(:namespace)
+
+      expect(relation.search(project.namespace.name)).to eq([project])
+    end
   end
 
   describe '#rename_repo' do