Merge branch '342857-fix-segfault-cross-db-modification-check' into 'master'

Workaround PGQuery.parse segfault again

See merge request gitlab-org/gitlab!72166

spec/support/database/prevent_cross_database_modification.rb

@@ -79,8 +79,17 @@ module Database
 
       return if cross_database_context[:transaction_depth_by_db].values.all?(&:zero?)
 
-      parsed_query = PgQuery.parse(sql)
-      tables = sql.downcase.include?(' for update') ? parsed_query.tables : parsed_query.dml_tables
+      # PgQuery might fail in some cases due to limited nesting:
+      # https://github.com/pganalyze/pg_query/issues/209
+      #
+      # Also, we disable GC while parsing because of https://github.com/pganalyze/pg_query/issues/226
+      begin
+        GC.disable
+        parsed_query = PgQuery.parse(sql)
+        tables = sql.downcase.include?(' for update') ? parsed_query.tables : parsed_query.dml_tables
+      ensure
+        GC.enable
+      end
 
       return if tables.empty?