Bug report

Bug description:

Bug report

Bug description:

InModules/_io/bufferedio.c, thebuffered_iternext function has a fast path that calls_buffered_readline directly to avoid method call overhead.
However, due to an incorrect type check, this fast path is never executed.

tp=Py_TYPE(self);if (Py_IS_TYPE(tp,state->PyBufferedReader_Type)||Py_IS_TYPE(tp,state->PyBufferedRandom_Type))

becausePy_IS_TYPE will callPy_TYPE internally, will cause Py_TYPE(Py_TYPE(ob)) == type,
<class 'type'> != state->PyBufferedReader_Type

All iteration over buffered binary files is affected:

withopen('data.txt','rb')asf:forlineinf:process(line)

CPython versions tested on:

CPython main branch

Operating systems tested on:

Linux

Linked PRs

• gh-144380: Fix incorrect type check inbuffered_iternext() #144381