Do null-check of error_context_stack before use

The variable is accessed without null checking when planner is called
in the context of pl/pgsql. Fix it. Back-patched up to pg_hint_plan94.

Reporter: egashira-yusuke
Issue: https://github.com/ossc-db/pg_hint_plan/issues/42
Original-Author: sun-wei <30999182+Dagouhan@users.noreply.github.com>
Original-patch: https://github.com/ossc-db/pg_hint_plan/pull/45/commits/8fe092ef73a9af6cfb41e20717d7cb35aa74fce2

diff --git a/pg_hint_plan.c b/pg_hint_plan.c
index b21fbfe..ce5d1a2 100644 (file)
--- a/pg_hint_plan.c
+++ b/pg_hint_plan.c
@@ -3019,7 +3019,8 @@ pg_hint_plan_planner(Query *parse, int cursorOptions, ParamListInfo boundParams)
         * Support for nested plpgsql functions. This is quite ugly but this is the
         * only point I could find where I can get the query string.
         */
-       if (plpgsql_recurse_level > 0)
+       if (plpgsql_recurse_level > 0 &&
+               error_context_stack && error_context_stack->arg)
        {
                MemoryContext oldcontext;