Avoid casting away const in sepgsql's quote_object_name.

tglsfdc · tglsfdc · commit 94077df1c2de · 2022-08-27T12:52:39.000-04:00
quote_identifier's API is designed on the assumption that it's not worth worrying about a short-term memory leak when we have to produce a quoted version of the given identifier. Whoever wrote quote_object_name took it on themselves to override that judgment, but the only way to do so is to cast away const someplace. We can avoid that and substantially shorten the function by going along with quote_identifier's opinion. AFAICS quote_object_name is not used in any way where this would be unsustainable. Per discussion of commit 45987aa, which exposed that we had a casting-away-const situation here. Discussion: https://postgr.es/m/20220827112304.GL2342@telsasoft.com
diff --git a/contrib/sepgsql/label.c b/contrib/sepgsql/label.c
@@ -646,45 +646,24 @@ sepgsql_mcstrans_out(PG_FUNCTION_ARGS)
 /*
  * quote_object_name
  *
- * It tries to quote the supplied identifiers
+ * Concatenate as many of the given strings as aren't NULL, with dots between.
+ * Quote any of the strings that wouldn't be valid identifiers otherwise.
  */
 static char *
 quote_object_name(const char *src1, const char *src2,
 				  const char *src3, const char *src4)
 {
 	StringInfoData result;
-	const char *temp;
 
 	initStringInfo(&result);
-
 	if (src1)
-	{
-		temp = quote_identifier(src1);
-		appendStringInfoString(&result, temp);
-		if (src1 != temp)
-			pfree(temp);
-	}
+		appendStringInfoString(&result, quote_identifier(src1));
 	if (src2)
-	{
-		temp = quote_identifier(src2);
-		appendStringInfo(&result, ".%s", temp);
-		if (src2 != temp)
-			pfree(temp);
-	}
+		appendStringInfo(&result, ".%s", quote_identifier(src2));
 	if (src3)
-	{
-		temp = quote_identifier(src3);
-		appendStringInfo(&result, ".%s", temp);
-		if (src3 != temp)
-			pfree(temp);
-	}
+		appendStringInfo(&result, ".%s", quote_identifier(src3));
 	if (src4)
-	{
-		temp = quote_identifier(src4);
-		appendStringInfo(&result, ".%s", temp);
-		if (src4 != temp)
-			pfree(temp);
-	}
+		appendStringInfo(&result, ".%s", quote_identifier(src4));
 	return result.data;
 }
 
