% formatted arguments put on new lines after multiline strings

[hugovk]

Operating system: macOS High Sierra
Python version: 3.7.2
Black version: 19.3b0
Does also happen on master: Yes, in more cases than 19.3b0

Look how the str(err) arguments are changed.

Input

def thing():
    err = 1

    msg = """Short docstring. %s""" % (str(err))

    msg = """Short docstring. %s %s""" % (str(err), str(err))

    msg = """

    This is a long docstring. This is a long docstring. This is a long docstring. 
    This is a long docstring. This is a long docstring. This is a long docstring. %s

    """ % (str(err))

    msg = """

This is a long docstring. This is a long docstring. This is a long docstring. %s
This is a long docstring. This is a long docstring. This is a long docstring. %s

""" % (str(err), str(err))

Output with 19.3b0

The str(err) arguments are put on their own lines for long docstrings. They don't need to be changed.

def thing():
    err = 1

    msg = """Short docstring. %s""" % (str(err))

    msg = """Short docstring. %s %s""" % (str(err), str(err))

    msg = """

    This is a long docstring. This is a long docstring. This is a long docstring. 
    This is a long docstring. This is a long docstring. This is a long docstring. %s

    """ % (
        str(err)
    )

    msg = """

This is a long docstring. This is a long docstring. This is a long docstring. %s
This is a long docstring. This is a long docstring. This is a long docstring. %s

""" % (
        str(err),
        str(err),
    )

Output with master

The str(err) arguments are put on their own lines, for long docstrings, and for short docstrings when there's two of them. They don't need to be changed.

def thing():
    err = 1

    msg = """Short docstring. %s""" % (str(err))

    msg = """Short docstring. %s %s""" % (
        str(err),
        str(err),
    )

    msg = """

    This is a long docstring. This is a long docstring. This is a long docstring. 
    This is a long docstring. This is a long docstring. This is a long docstring. %s

    """ % (
        str(err)
    )

    msg = """

This is a long docstring. This is a long docstring. This is a long docstring. %s
This is a long docstring. This is a long docstring. This is a long docstring. %s

""" % (
        str(err),
        str(err),
    )

https://black.now.sh/?version=master&state=_Td6WFoAAATm1rRGAgAhARYAAAB0L-Wj4AKQAKBdAD2IimZxl1N_WlbvK5V_5XC4HPsJew3HOF1BHgQimRfSJ9q84dUyrSjb0mQnAO7rr9vjV_k61P_liPqH1s3nyKQ1P1dZ74Cja8iu64pXfCf70kAMFzhqj9sC39JI8T_XaEXuIQZyt0F1B4goQbLb0FBmreVkuA-cF_gcpYU3CTJ3yV-c-zcLZ68E2Vq_j3MdTDfxR4OlZ6ESiHDhBXbdK2AAF22UCo9c44sAAbwBkQUAAElqCpCxxGf7AgAAAAAEWVo=

[RedGuy12]

This issue has been long fixed with the unstable multiline_string_handling feature.