From 7394c763bc72db90cbca0fca8a17f96cc2bcc6f7 Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Mon, 19 Sep 2022 12:16:02 -0400 Subject: [PATCH] Future-proof the recursion inside ExecShutdownNode(). The API contract for planstate_tree_walker() callbacks is that they take a PlanState pointer and a context pointer. Somebody figured they could save a couple lines of code by ignoring that, and passing ExecShutdownNode itself as the walker even though it has but one argument. Somewhat remarkably, we've gotten away with that so far. However, it seems clear that the upcoming C2x standard means to forbid such cases, and compilers that actively break such code likely won't be far behind. So spend the extra few lines of code to do it honestly with a separate walker function. In HEAD, we might as well go further and remove ExecShutdownNode's useless return value. I left that as-is in back branches though, to forestall complaints about ABI breakage. Back-patch, with the thought that this might become of practical importance before our stable branches are all out of service. It doesn't seem to be fixing any live bug on any currently known platform, however. Discussion: https://postgr.es/m/208054.1663534665@sss.pgh.pa.us --- src/backend/executor/execProcnode.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/src/backend/executor/execProcnode.c b/src/backend/executor/execProcnode.c index 1752b9bfd81..9b2c436f737 100644 --- a/src/backend/executor/execProcnode.c +++ b/src/backend/executor/execProcnode.c @@ -121,6 +121,7 @@ static TupleTableSlot *ExecProcNodeFirst(PlanState *node); static TupleTableSlot *ExecProcNodeInstr(PlanState *node); +static bool ExecShutdownNode_walker(PlanState *node, void *context); /* ------------------------------------------------------------------------ @@ -770,6 +771,12 @@ ExecEndNode(PlanState *node) */ bool ExecShutdownNode(PlanState *node) +{ + return ExecShutdownNode_walker(node, NULL); +} + +static bool +ExecShutdownNode_walker(PlanState *node, void *context) { if (node == NULL) return false; @@ -789,7 +796,7 @@ ExecShutdownNode(PlanState *node) if (node->instrument && node->instrument->running) InstrStartNode(node->instrument); - planstate_tree_walker(node, ExecShutdownNode, NULL); + planstate_tree_walker(node, ExecShutdownNode_walker, context); switch (nodeTag(node)) {