Support rails5 in postgres indexes function and fix some migrations

changelogs/unreleased/rails5-fix-46236.yml

+---
+title: Support rails5 in postgres indexes function and fix some migrations
+merge_request: 19400
+author: Jasper Maes
+type: fixed

config/initializers/postgresql_opclasses_support.rb

@@ -107,8 +107,15 @@ module ActiveRecord
           result.map do |row|
             index_name = row[0]
-            unique = row[1] == 't'
+            unique = if Gitlab.rails5?
+                       row[1]
+                     else
+                       row[1] == 't'
+                     end
             indkey = row[2].split(" ")
+            if Gitlab.rails5?
+              indkey = indkey.map(&:to_i)
+            end
             inddef = row[3]
             oid = row[4]

db/migrate/20160226114608_add_trigram_indexes_for_searching.rb

@@ -37,7 +37,12 @@ class AddTrigramIndexesForSearching < ActiveRecord::Migration
     res = execute("SELECT true AS enabled FROM pg_available_extensions WHERE name = 'pg_trgm' AND installed_version IS NOT NULL;")
     row = res.first
-    row && row['enabled'] == 't' ? true : false
+    check = if Gitlab.rails5?
+              true
+            else
+              't'
+            end
+    row && row['enabled'] == check ? true : false
   end
   def create_trigrams_extension

db/migrate/20170622135728_add_unique_constraint_to_ci_variables.rb

@@ -2,12 +2,13 @@ class AddUniqueConstraintToCiVariables < ActiveRecord::Migration
   include Gitlab::Database::MigrationHelpers
   DOWNTIME = false
+  INDEX_NAME = 'index_ci_variables_on_project_id_and_key_and_environment_scope'
   disable_ddl_transaction!
   def up
     unless this_index_exists?
-      add_concurrent_index(:ci_variables, columns, name: index_name, unique: true)
+      add_concurrent_index(:ci_variables, columns, name: INDEX_NAME, unique: true)
     end
   end
@@ -18,21 +19,17 @@ class AddUniqueConstraintToCiVariables < ActiveRecord::Migration
         add_concurrent_index(:ci_variables, :project_id)
       end
-      remove_concurrent_index(:ci_variables, columns, name: index_name)
+      remove_concurrent_index(:ci_variables, columns, name: INDEX_NAME)
     end
   end
   private
   def this_index_exists?
-    index_exists?(:ci_variables, columns, name: index_name)
+    index_exists?(:ci_variables, columns, name: INDEX_NAME)
   end
   def columns
     @columns ||= [:project_id, :key, :environment_scope]
   end
-
-  def index_name
-    'index_ci_variables_on_project_id_and_key_and_environment_scope'
-  end
 end

db/migrate/20171106155656_turn_issues_due_date_index_to_partial_index.rb

@@ -20,9 +20,7 @@ class TurnIssuesDueDateIndexToPartialIndex < ActiveRecord::Migration
       name: NEW_INDEX_NAME
     )
-    # We set the column name to nil as otherwise Rails will ignore the custom
-    # index name and remove the wrong index.
-    remove_concurrent_index(:issues, nil, name: OLD_INDEX_NAME)
+    remove_concurrent_index_by_name(:issues, OLD_INDEX_NAME)
   end
   def down
@@ -32,6 +30,6 @@ class TurnIssuesDueDateIndexToPartialIndex < ActiveRecord::Migration
       name: OLD_INDEX_NAME
     )
-    remove_concurrent_index(:issues, nil, name: NEW_INDEX_NAME)
+    remove_concurrent_index_by_name(:issues, NEW_INDEX_NAME)
   end
 end

db/migrate/20180201110056_add_foreign_keys_to_todos.rb

@@ -31,7 +31,7 @@ class AddForeignKeysToTodos < ActiveRecord::Migration
   end
   def down
-    remove_foreign_key :todos, :users
+    remove_foreign_key :todos, column: :user_id
     remove_foreign_key :todos, column: :author_id
     remove_foreign_key :todos, :notes
   end