Weird XkbGetKeyboardByName() behaviour when dealing with key names

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I noticed that, at least on my system, XkbGetKeyboardByName returns NULL  
when the 'names' argument is NULL and the 'which' argument is  
XkbGBN_KeyNameMask. A NULL is also returned if 'names' points to a valid  
XkbComponentNamesRec whose every component is NULL. However, according to  
the XKB Library Specification, page 219:

"If a required component has not been specified in the names structure  
(the corresponding field is NULL ), the server substitutes the expression  
"%", resulting in the component values being taken from device_spec."

It seems to me that XkbGetKeyboardByName should return a valid XkbDescPtr  
even if the 'names' is NULL or filled with NULLs. Since it doesn't, it  
make XkbGetKeyboard useless when dealing with key names, since  
XkbGetKeyboard calls XkbGetKeyboardByName with 'names' = NULL.

Another thing I noticed was that XkbGetKeyboardByName does not write a  
correct value to XkbDescRec.names.num_keys, even though the 'keys' field  
seems to contain the valid values. As far as I know, the specification  
does not say that the field would be filled by XkbGetKeyboardByname, but I  
think that's just an error in the specification. On the other hand, the  
specification does say that XkbGetNames fills the 'num_keys' field when  
called with 'which'=XkbKeyNamesMask. The implementation, however,  
leaves/sets the 'num_keys' to zero.

Am I doing something wrong, or are these flaws in the specification /  
implementation? I've added a simple example program that shows the problem.
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