From 574bf16ff1f836a442d8de1853eb248c218a591d Mon Sep 17 00:00:00 2001 From: Markus Armbruster Date: Thu, 23 Aug 2018 18:39:50 +0200 Subject: [PATCH] json: Report first rather than last parse error Quiz time! When a parser reports multiple errors, but the user gets to see just one, which one is (on average) the least useful one? Yes, you're right, it's the last one! You're clearly familiar with compilers. Which one does QEMU report? Right again, the last one! You're clearly familiar with QEMU. Reproducer: feeding {"abc\xC2ijk": 1}\n to QMP produces {"error": {"class": "GenericError", "desc": "JSON parse error, key is not a string in object"}} Report the first error instead. The reproducer now produces {"error": {"class": "GenericError", "desc": "JSON parse error, invalid UTF-8 sequence in string"}} Signed-off-by: Markus Armbruster Reviewed-by: Eric Blake Message-Id: <20180823164025.12553-24-armbru@redhat.com> --- qobject/json-parser.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/qobject/json-parser.c b/qobject/json-parser.c index 0e232ff101..b77931614b 100644 --- a/qobject/json-parser.c +++ b/qobject/json-parser.c @@ -54,13 +54,13 @@ static void GCC_FMT_ATTR(3, 4) parse_error(JSONParserContext *ctxt, { va_list ap; char message[1024]; + + if (ctxt->err) { + return; + } va_start(ap, msg); vsnprintf(message, sizeof(message), msg, ap); va_end(ap); - if (ctxt->err) { - error_free(ctxt->err); - ctxt->err = NULL; - } error_setg(&ctxt->err, "JSON parse error, %s", message); }