From: Peter Eisentraut <peter@eisentraut.org>
Date: Thu, 14 Mar 2019 07:25:25 +0000 (+0100)
Subject: Fix volatile vs. pointer confusion
X-Git-Tag: REL9_5_17~44
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=361cabb11d36afaf466d76e1bda1778501137dcf;p=postgresql

Fix volatile vs. pointer confusion

Variables used after a longjmp() need to be declared volatile.  In
case of a pointer, it's the pointer itself that needs to be declared
volatile, not the pointed-to value.  So we need

    PyObject *volatile items;

instead of

    volatile PyObject *items;  /* wrong */

Discussion: https://www.postgresql.org/message-id/flat/f747368d-9e1a-c46a-ac76-3c27da32e8e4%402ndquadrant.com
---

diff --git a/contrib/hstore_plpython/hstore_plpython.c b/contrib/hstore_plpython/hstore_plpython.c
index 6f2751a8df..155b3028e7 100644
--- a/contrib/hstore_plpython/hstore_plpython.c
+++ b/contrib/hstore_plpython/hstore_plpython.c
@@ -51,7 +51,7 @@ Datum
 plpython_to_hstore(PG_FUNCTION_ARGS)
 {
 	PyObject   *dict;
-	volatile PyObject *items_v = NULL;
+	PyObject *volatile items = NULL;
 	int32		pcount;
 	HStore	   *out;
 
@@ -62,14 +62,13 @@ plpython_to_hstore(PG_FUNCTION_ARGS)
 				 errmsg("not a Python mapping")));
 
 	pcount = PyMapping_Size(dict);
-	items_v = PyMapping_Items(dict);
+	items = PyMapping_Items(dict);
 
 	PG_TRY();
 	{
 		int32		buflen;
 		int32		i;
 		Pairs	   *pairs;
-		PyObject   *items = (PyObject *) items_v;
 
 		pairs = palloc(pcount * sizeof(*pairs));
 
@@ -100,14 +99,14 @@ plpython_to_hstore(PG_FUNCTION_ARGS)
 				pairs[i].isnull = false;
 			}
 		}
-		Py_DECREF(items_v);
+		Py_DECREF(items);
 
 		pcount = hstoreUniquePairs(pairs, pcount, &buflen);
 		out = hstorePairs(pairs, pcount, buflen);
 	}
 	PG_CATCH();
 	{
-		Py_DECREF(items_v);
+		Py_DECREF(items);
 		PG_RE_THROW();
 	}
 	PG_END_TRY();