Prevent creating window functions with default arguments.

tglsfdc · tglsfdc · commit aad87e3f25ad · 2013-11-06T13:32:26.000-05:00
Insertion of default arguments doesn't work for window functions, which is
likely to cause a crash at runtime if the implementation code doesn't check
the number of actual arguments carefully.  It doesn't seem worth working
harder than this for pre-9.2 branches.
diff --git a/doc/src/sgml/syntax.sgml b/doc/src/sgml/syntax.sgml
@@ -2464,6 +2464,13 @@ SELECT concat_lower_or_upper('Hello', 'World', uppercase := true);
     having numerous parameters that have default values, named or mixed
     notation can save a great deal of writing and reduce chances for error.
    </para>
+
+   <note>
+    <para>
+     Named and mixed call notations can currently be used only with regular
+     functions, not with aggregate functions or window functions.
+    </para>
+   </note>
   </sect2>
  </sect1>
 
diff --git a/src/backend/catalog/pg_proc.c b/src/backend/catalog/pg_proc.c
@@ -285,6 +285,12 @@ ProcedureCreate(const char *procedureName,
 		}
 	}
 
+	/* Guard against a case the planner doesn't handle yet */
+	if (isWindowFunc && parameterDefaults != NIL)
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("window functions cannot have default arguments")));
+
 	/*
 	 * All seems OK; prepare the data to be inserted into pg_proc.
 	 */

Original file line number	Diff line number	Diff line change
`@@ -285,6 +285,12 @@ ProcedureCreate(const char *procedureName,`
`285`	`285`	`}`
`286`	`286`	`}`
`287`	`287`
	`288`	`+ /* Guard against a case the planner doesn't handle yet */`
	`289`	`+ if (isWindowFunc && parameterDefaults != NIL)`
	`290`	`+ ereport(ERROR,`
	`291`	`+ (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),`
	`292`	`+ errmsg("window functions cannot have default arguments")));`
	`293`	`+`
`288`	`294`	`/*`
`289`	`295`	`* All seems OK; prepare the data to be inserted into pg_proc.`
`290`	`296`	`*/`