Remove an XXX command suggesting that this truncation should not be conditional,

and also add a more verbose comment explaining why it is only needed in the
case of appending to the string for any curious readers that come along in the
future.


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@48103 65c4cc65-6c06-0410-ace0-fbb531ad65f3

main/utils.c

@@ -997,7 +997,14 @@ int ast_dynamic_str_thread_build_va(struct ast_dynamic_str **buf, size_t max_len
 			return AST_DYNSTR_BUILD_FAILED;
 		(*buf)->len = need;
 
-		/* Truncate the previous attempt. XXX this should be unconditional */
+		/* Truncate the previous attempt.  This is only needed for the
+		 * append operation because if the write is from the beginning,
+		 * it will get automatically overwritten when this function
+		 * gets called again.  When appending, if this was not done,
+		 * this function would be called over and over again, because
+		 * each attempt would be appending more and more partial
+		 * strings, never having enough space to finish.
+		 */ 
 		if (append)
 			(*buf)->str[offset] = '\0';