Fix portability issue in ordered-set patch.

tglsfdc · tglsfdc · commit cf63c641cae2 · 2013-12-23T20:24:07.000-05:00
Overly compact coding in makeOrderedSetArgs() led to a platform dependency:
if the compiler chose to execute the subexpressions in the wrong order,
list_length() might get applied to an already-modified List, giving a
value we didn't want.  Per buildfarm.
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
@@ -13385,6 +13385,7 @@ makeOrderedSetArgs(List *directargs, List *orderedargs,
 				   core_yyscan_t yyscanner)
 {
 	FunctionParameter *lastd = (FunctionParameter *) llast(directargs);
+	int			ndirectargs;
 
 	/* No restriction unless last direct arg is VARIADIC */
 	if (lastd->mode == FUNC_PARAM_VARIADIC)
@@ -13407,8 +13408,11 @@ makeOrderedSetArgs(List *directargs, List *orderedargs,
 		orderedargs = NIL;
 	}
 
+	/* don't merge into the next line, as list_concat changes directargs */
+	ndirectargs = list_length(directargs);
+
 	return list_make2(list_concat(directargs, orderedargs),
-					  makeInteger(list_length(directargs)));
+					  makeInteger(ndirectargs));
 }
 
 /* insertSelectOptions()

Original file line number	Diff line number	Diff line change
`@@ -13385,6 +13385,7 @@ makeOrderedSetArgs(List directargs, List orderedargs,`
`13385`	`13385`	`core_yyscan_t yyscanner)`
`13386`	`13386`	`{`
`13387`	`13387`	`FunctionParameter lastd = (FunctionParameter ) llast(directargs);`
	`13388`	`+ int ndirectargs;`
`13388`	`13389`
`13389`	`13390`	`/* No restriction unless last direct arg is VARIADIC */`
`13390`	`13391`	`if (lastd->mode == FUNC_PARAM_VARIADIC)`
`@@ -13407,8 +13408,11 @@ makeOrderedSetArgs(List directargs, List orderedargs,`
`13407`	`13408`	`orderedargs = NIL;`
`13408`	`13409`	`}`
`13409`	`13410`
	`13411`	`+ /* don't merge into the next line, as list_concat changes directargs */`
	`13412`	`+ ndirectargs = list_length(directargs);`
	`13413`	`+`
`13410`	`13414`	`return list_make2(list_concat(directargs, orderedargs),`
`13411`		`- makeInteger(list_length(directargs)));`
	`13415`	`+ makeInteger(ndirectargs));`
`13412`	`13416`	`}`
`13413`	`13417`
`13414`	`13418`	`/* insertSelectOptions()`