[Python-Dev] How to fix the buffer object's broken char buffer support (original) (raw)

Guido van Rossum guido at python.org
Wed Jun 7 04:13:43 CEST 2006

On 6/6/06, Brett Cannon <brett at python.org> wrote:

If you run import array; int(buffer(array.array('c'))) the interpreter will segfault. While investigating this I discovered that buffer objects, for their tpasbuffer->bfgetcharbuffer, return the result by calling the wrapped object bfgetreadbuffer or bfgetwritebuffer. This is wrong since it is essentially redirecting the expected call to the wrong tpasbuffer slot for the wrapped object. Plus it doesn't have PyTPFLAGSHAVEGETCHARBUFFER defined.

I see two options here. One is to remove the bfgetcharbuffer slot from the buffer object. The other option is to fix it so that it only returns bfgetcharbuffer and doesn't redirect improperly (this also brings up the issue if PyTPFLAGSHAVEGETCHARBUFFER should then also be defined for buffer objects). Since I don't use buffer objects I don't know if it is better to fix this or just rip it out.

How ironic. the charbuffer slot was added late in the game -- now we'd be ripping it out...

I suspect that there's a reason for it; but in Py3k it will definitely be ripped out. Buffers will purely deal in byte then, never in characters; you won't be able to get a buffer from a (unicode) string at all.

Unhelpfully,

-- --Guido van Rossum (home page: http://www.python.org/~guido/)

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