tags 21376 + patch
quit

Eli Zaretskii <eliz@gnu.org> writes:

> 4 of the Python tests fail on MS-Windows due to some issue related to
> the prompts displayed by the Python interpreter.  The 4 failed tests
> are:
>
>    FAILED  python-shell-make-comint-4
>    FAILED  python-shell-prompt-detect-1
>    FAILED  python-shell-prompt-detect-2
>    FAILED  python-shell-prompt-set-calculated-regexps-6
>
> I show below the relevant portions of python-tests.log.
>
> I need help in figuring out what causes these.  One possible suspect
> is some buffering issue, due to which Emacs does not receive the
> prompt that Python prints.  Another possibility might be the version
> of the Python (I have 2.6.6 installed).  Or maybe something else.

It seems to be a bug in Python 2.x on Windows (Python 3.6.x doesn't show
the problem).  In unbuffered mode it rejects carriage returns.  Compare
results of

    printf 'print("hello world")\r\n' > hello-world-with-crnl.py
    python -i    < hello-world-with-crnl.py
    python -i -u < hello-world-with-crnl.py

    printf 'print("hello world")\n' > hello-world-with-nl.py
    python -i    < hello-world-with-nl.py
    python -i -u < hello-world-with-nl.py

(Setting the PYTHONUNBUFFERED environment variable, as python.el does,
is equivalent to passing '-u'.)

The bug can be worked around with the following patch: