Merge branch '343607-improve-error-message-undefined-cross-modifications' into 'master'

Improve cross-modification error message for undefined gitlab_schema

See merge request gitlab-org/gitlab!72945

spec/support/database/prevent_cross_database_modification.rb

@@ -102,10 +102,15 @@ module Database
       schemas = Database::GitlabSchema.table_schemas(all_tables)
 
       if schemas.many?
-        raise Database::PreventCrossDatabaseModification::CrossDatabaseModificationAcrossUnsupportedTablesError,
-          "Cross-database data modification of '#{schemas.to_a.join(", ")}' were detected within " \
+        message = "Cross-database data modification of '#{schemas.to_a.join(", ")}' were detected within " \
           "a transaction modifying the '#{all_tables.to_a.join(", ")}' tables." \
           "Please refer to https://docs.gitlab.com/ee/development/database/multiple_databases.html#removing-cross-database-transactions for details on how to resolve this exception."
+
+        if schemas.any? { |s| s.to_s.start_with?("undefined") }
+          message += " The gitlab_schema was undefined for one or more of the tables in this transaction. Any new tables must be added to spec/support/database/gitlab_schemas.yml ."
+        end
+
+        raise Database::PreventCrossDatabaseModification::CrossDatabaseModificationAcrossUnsupportedTablesError, message
       end
     end
   end

spec/support_specs/database/prevent_cross_database_modification_spec.rb

@@ -68,6 +68,17 @@ RSpec.describe 'Database::PreventCrossDatabaseModification' do
         end
       end.to raise_error /Cross-database data modification/
     end
+
+    it 'raises an error when an undefined gitlab_schema table is modified with another table' do
+      expect do
+        with_cross_database_modification_prevented do
+          Project.transaction do
+            project.touch
+            project.connection.execute('UPDATE foo_bars_undefined_table SET a=1 WHERE id = -1')
+          end
+        end
+      end.to raise_error /Cross-database data modification.*The gitlab_schema was undefined/
+    end
   end
 
   context 'when running tests with prevent_cross_database_modification', :prevent_cross_database_modification do