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_pyio.TextIOBase.read is missing a size arg #151596

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_pyio.TextIOBase.read is missing a size arg#151596
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pendingThe issue will be closed if no feedback is providedstdlibStandard Library Python modules in the Lib/ directorytopic-IOtype-bugAn unexpected behavior, bug, or error
@ShaharNaveh

Description

@ShaharNaveh
ShaharNaveh
opened on Jun 17, 2026

Bug report

Bug description:

IOBase:

cpython/Lib/_pyio.py

Line 513 in a064b32

def readline(self, size=-1):

TextIOBase:

cpython/Lib/_pyio.py

Line 1931 in a064b32

def readline(self):

This pattern seems to be missing only for readline AFAICT.
for truncate (which is also "unsupported" for TextIOBase) it's preserved:

IOBase:

cpython/Lib/_pyio.py

Line 370 in a064b32

def truncate(self, pos=None):

TextIOBase:

cpython/Lib/_pyio.py

Line 1927 in a064b32

def truncate(self, pos=None):

(the same for write and others).

My proposed fix should be adding a size argument to readline with a default value of -1

CPython versions tested on:

CPython main branch

Operating systems tested on:

Linux

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    pendingThe issue will be closed if no feedback is providedstdlibStandard Library Python modules in the Lib/ directorytopic-IOtype-bugAn unexpected behavior, bug, or error

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