From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Sat, 18 Oct 2014 02:32:55 +0000 (-0400)
Subject: Avoid core dump in _outPathInfo() for Path without a parent RelOptInfo.
X-Git-Tag: REL9_5_ALPHA1~1347
X-Git-Url: http://git.postgresql.org/gitweb/?a=commitdiff_plain;h=5ba062ee44c35b4dc49ccf869fe48f3c6f5f926f;p=postgresql.git

Avoid core dump in _outPathInfo() for Path without a parent RelOptInfo.

Nearly all Paths have parents, but a ResultPath representing an empty FROM
clause does not.  Avoid a core dump in such cases.  I believe this is only
a hazard for debugging usage, not for production, else we'd have heard
about it before.  Nonetheless, back-patch to 9.1 where the troublesome code
was introduced.  Noted while poking at bug #11703.
---

diff --git a/src/backend/nodes/outfuncs.c b/src/backend/nodes/outfuncs.c
index 56e486c8bc8..4bbfa629d69 100644
--- a/src/backend/nodes/outfuncs.c
+++ b/src/backend/nodes/outfuncs.c
@@ -1477,7 +1477,10 @@ _outPathInfo(StringInfo str, const Path *node)
 {
 	WRITE_ENUM_FIELD(pathtype, NodeTag);
 	appendStringInfoString(str, " :parent_relids ");
-	_outBitmapset(str, node->parent->relids);
+	if (node->parent)
+		_outBitmapset(str, node->parent->relids);
+	else
+		_outBitmapset(str, NULL);
 	appendStringInfoString(str, " :required_outer ");
 	if (node->param_info)
 		_outBitmapset(str, node->param_info->ppi_req_outer);