I suggest adding validation of the timer handle ("configASSERT( xTimer )") in the functions xTimerGenericCommand(), pcTimerGetTimerName(), and xTimerIsTimerActive().
pvTimerGetTimerID() and vTimerSetTimerID() already contain this test, but the other functions do not.
Thanks for your suggestion. At first when reading your post I thought there must be a reason why this was not include din xTimerGenericCommand(), but looking at the code, if there is a reason it is not obvious, so I have added it to my local copy. If I don't run into any issues it will get checked in and included in the next version (I have added it to the other functions you suggest too).