Handle NULL fields in WRITE_INDEX_ARRAY

petere · petere · commit 9ddf251f9409 · 2022-04-27T09:15:09.000+02:00
Unlike existing WRITE_*_ARRAY macros, WRITE_INDEX_ARRAY needs to handle the case that the field is NULL. We already have the convention to print NULL fields as "<>", so we do that here as well. There is currently no corresponding read function for this, so reading this back in is not implemented, but it could be if needed. Reported-by: Richard Guo <guofenglinux@gmail.com> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> Discussion: https://www.postgresql.org/message-id/flat/CAMbWs4-LN%3DbF8f9eU2R94dJtF54DfDvBq%2BovqHnOQqbinYDrUw%40mail.gmail.com
diff --git a/src/backend/nodes/outfuncs.c b/src/backend/nodes/outfuncs.c
@@ -124,11 +124,18 @@ static void outChar(StringInfo str, char c);
 			appendStringInfo(str, " %u", node->fldname[i]); \
 	} while(0)
 
+/*
+ * This macro supports the case that the field is NULL.  For the other array
+ * macros, that is currently not needed.
+ */
 #define WRITE_INDEX_ARRAY(fldname, len) \
 	do { \
 		appendStringInfoString(str, " :" CppAsString(fldname) " "); \
-		for (int i = 0; i < len; i++) \
-			appendStringInfo(str, " %u", node->fldname[i]); \
+		if (node->fldname) \
+			for (int i = 0; i < len; i++) \
+				appendStringInfo(str, " %u", node->fldname[i]); \
+		else \
+			appendStringInfoString(str, "<>"); \
 	} while(0)
 
 #define WRITE_INT_ARRAY(fldname, len) \
