[Python-3000] PyBUF_LOCK fails on bytes objects. they're read-only, why should it fail?

[Travis Oliphant]

Gregory P. Smith wrote:
> bytes objects are by their definition immutable and read only.  but when 
> passing one to a buffer api that tries to use the PyBUF_LOCK flag it 
> raises BufferError "Cannot lock this object." from PyBuffer_FillInfo in 
> Objects/abstract.c as called by Objects/bytesobject.c's bytes_getbuffer 
> method.
> 
> I think the problem is a >= 0 where a != 0 was intended in 
> PyBuffer_FillInfo:
> 
> --- Objects/abstract.c  (revision 61375)
> +++ Objects/abstract.c  (working copy)
> @@ -673,7 +673,7 @@
>  {
>         if (view == NULL) return 0;
>         if (((flags & PyBUF_LOCK) == PyBUF_LOCK) &&
> -           readonly >= 0) {
> +           readonly != 0) {
>                 PyErr_SetString(PyExc_BufferError,
>                                 "Cannot lock this object.");
>                 return -1;
> 
>

Good catch.  This looks like a good fix.

-Travis O.