Public bug reported: Hi, We have VMs which were started with an older version than qemu 2.1 which added "cache-miss-rate" property for XBZRLECacheStats. While trying to migrate the VM to a new host which is running a higher version (2.3) of Qemu we got an exception: virJSONValueFromString:1642 : internal error: cannot parse json {"return": {"expected-downtime": 1, "xbzrle-cache": {"bytes": 0, "cache-size": 67108864, "cache-miss-rate": -nan, "pages": 0, "overflow": 0, "cache-miss": 8933}, "status": "active", "disk": {"total": 429496729600, "dirty-sync-count": 0, "remaining": 193896382464, "mbps": 0, "transferred": 235600347136, "duplicate": 0, "dirty-pages-rate": 0, "skipped": 0, "normal-bytes": 0, "normal": 0}, "setup-time": 13, "total-time": 1543124, "ram": {"total": 8599183360, "dirty-sync-count": 4, "remaining": 30695424, "mbps": 830.636997, "transferred": 3100448901, "duplicate": 1358341, "dirty-pages-rate": 7, "skipped": 0, "normal-bytes": 3082199040, "normal": 752490}}, "id": "libvirt-186200"}: lexical error: malformed number, a digit is required after the minus sign. 67108864, "cache-miss-rate": -nan, "pages": 0, "overflow": 0 (right here) ------^ virNetClientStreamRaiseError:191 : stream aborted at client request

Would it be possible to improve the JSON parser to skip the key if the value is incorrect