[Qemu-devel] [PULL 06/14] qmp: fix qmp_capabilities error regression

[Eric Blake <eblake@redhat.com>]

From: Peter Xu <peterx@redhat.com>

When someone sends a command before QMP handshake, the error used to be
like this:

 {"execute": "query-cpus"}
 {"error": {"class": "CommandNotFound", "desc":
            "Expecting capabilities negotiation with 'qmp_capabilities'"}}

While after cf869d5317 it becomes:

 {"execute": "query-cpus"}
 {"error": {"class": "CommandNotFound", "desc":
            "The command query-cpus has not been found"}}

Fix it back to the nicer one.

Fixes: cf869d5317 ("qmp: support out-of-band (oob) execution", 2018-03-19)
Reported-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Message-Id: <20180326063901.27425-2-peterx@redhat.com>
Reported-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
[eblake: commit message grammar tweaks]
Signed-off-by: Eric Blake <eblake@redhat.com>
---
 monitor.c | 23 ++++++++---------------
 1 file changed, 8 insertions(+), 15 deletions(-)

diff --git a/monitor.c b/monitor.c
index de709fc2e5d..3b1ef34711b 100644
--- a/monitor.c
+++ b/monitor.c
@@ -1203,8 +1203,14 @@ static bool qmp_cmd_oob_check(Monitor *mon, QDict *req, Error **errp)

     cmd = qmp_find_command(mon->qmp.commands, command);
     if (!cmd) {
-        error_set(errp, ERROR_CLASS_COMMAND_NOT_FOUND,
-                  "The command %s has not been found", command);
+        if (mon->qmp.commands == &qmp_cap_negotiation_commands) {
+            error_set(errp, ERROR_CLASS_COMMAND_NOT_FOUND,
+                      "Expecting capabilities negotiation "
+                      "with 'qmp_capabilities'");
+        } else {
+            error_set(errp, ERROR_CLASS_COMMAND_NOT_FOUND,
+                      "The command %s has not been found", command);
+        }
         return false;
     }

@@ -4027,7 +4033,6 @@ static void monitor_qmp_dispatch_one(QMPRequest *req_obj)
 {
     Monitor *mon, *old_mon;
     QObject *req, *rsp = NULL, *id;
-    QDict *qdict = NULL;
     bool need_resume;

     req = req_obj->req;
@@ -4050,18 +4055,6 @@ static void monitor_qmp_dispatch_one(QMPRequest *req_obj)

     cur_mon = old_mon;

-    if (mon->qmp.commands == &qmp_cap_negotiation_commands) {
-        qdict = qdict_get_qdict(qobject_to(QDict, rsp), "error");
-        if (qdict
-            && !g_strcmp0(qdict_get_try_str(qdict, "class"),
-                    QapiErrorClass_str(ERROR_CLASS_COMMAND_NOT_FOUND))) {
-            /* Provide a more useful error message */
-            qdict_del(qdict, "desc");
-            qdict_put_str(qdict, "desc", "Expecting capabilities negotiation"
-                          " with 'qmp_capabilities'");
-        }
-    }
-
     /* Respond if necessary */
     monitor_qmp_respond(mon, rsp, NULL, id);

-- 
2.14.3