fix crash on RESET ALL (issue #121)

Author: funbringer

expected/pathman_calamity.out

@@ -855,6 +855,25 @@ NOTICE:  drop cascades to 2 other objects
 DROP SCHEMA calamity CASCADE;
 NOTICE:  drop cascades to 15 other objects
 DROP EXTENSION pg_pathman;
+/*
+ * -------------------------------
+ *  Special tests (SET statement)
+ * -------------------------------
+ */
+CREATE EXTENSION pg_pathman;
+SET pg_pathman.enable = false;
+NOTICE:  RuntimeAppend, RuntimeMergeAppend and PartitionFilter nodes and some other options have been disabled
+SET pg_pathman.enable = true;
+NOTICE:  RuntimeAppend, RuntimeMergeAppend and PartitionFilter nodes and some other options have been enabled
+SET pg_pathman.enable = false;
+NOTICE:  RuntimeAppend, RuntimeMergeAppend and PartitionFilter nodes and some other options have been disabled
+RESET pg_pathman.enable;
+NOTICE:  RuntimeAppend, RuntimeMergeAppend and PartitionFilter nodes and some other options have been enabled
+RESET ALL;
+BEGIN; ROLLBACK;
+BEGIN ISOLATION LEVEL SERIALIZABLE; ROLLBACK;
+BEGIN; SET TRANSACTION ISOLATION LEVEL SERIALIZABLE; ROLLBACK;
+DROP EXTENSION pg_pathman;
 /*
  * -------------------------------------
  *  Special tests (pathman_cache_stats)

sql/pathman_calamity.sql

@@ -369,6 +369,27 @@ DROP EXTENSION pg_pathman;
 
 
 
+/*
+ * -------------------------------
+ *  Special tests (SET statement)
+ * -------------------------------
+ */
+
+CREATE EXTENSION pg_pathman;
+
+SET pg_pathman.enable = false;
+SET pg_pathman.enable = true;
+SET pg_pathman.enable = false;
+RESET pg_pathman.enable;
+RESET ALL;
+BEGIN; ROLLBACK;
+BEGIN ISOLATION LEVEL SERIALIZABLE; ROLLBACK;
+BEGIN; SET TRANSACTION ISOLATION LEVEL SERIALIZABLE; ROLLBACK;
+
+DROP EXTENSION pg_pathman;
+
+
+
 /*
  * -------------------------------------
  *  Special tests (pathman_cache_stats)

src/xact_handling.c

@@ -125,8 +125,15 @@ xact_is_set_stmt(Node *stmt, const char *name)
 	if (!IsA(stmt, VariableSetStmt))
 		return false;
 
-	if (!name || pg_strcasecmp(name, ((VariableSetStmt *) stmt)->name) == 0)
+	if (!name)
 		return true;
+	else
+	{
+		char *set_name = ((VariableSetStmt *) stmt)->name;
+
+		if (set_name && pg_strcasecmp(name, set_name) == 0)
+			return true;
+	}
 
 	return false;
 }