[issue28162] WindowsConsoleIO readall() fails if first line starts with Ctrl+Z

[Eryk Sun]

New submission from Eryk Sun:

For a console readall(), if the first line starts with '\x1a' (i.e. Ctrl+Z), it breaks out of its read loop before incrementing len. Thus the input isn't handled properly as EOF, for which the check requires len > 0. Instead it ends up calling WideCharToMultiByte with len == 0, which fails as follows:

    >>> sys.stdin.buffer.raw.read()
    ^Z
    Traceback (most recent call last):
      File "<stdin>", line 1, in <module>
    OSError: [WinError 87] The parameter is incorrect

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components: IO, Library (Lib), Windows
messages: 276508
nosy: eryksun, paul.moore, steve.dower, tim.golden, zach.ware
priority: normal
severity: normal
stage: test needed
status: open
title: WindowsConsoleIO readall() fails if first line starts with Ctrl+Z
type: behavior
versions: Python 3.6, Python 3.7

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Python tracker <report at bugs.python.org>
<http://bugs.python.org/issue28162>
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