[BUG] One trailing newline ignored by rich.print in some cases

[mportesdev]

Hi, thanks for this great library.

Not sure if this is expected behavior or a bug. In certain cases, rich.print handles newlines in a slightly different manner than the print built-in.

Example:

>>> for i in range(3): print('Hey' + '\n' * i)
... 
Hey
Hey

Hey


>>> from rich import print
>>> for i in range(3): print('Hey' + '\n' * i)
... 
Hey
Hey
Hey

>>> 

Apparently, when the printed string contains at least one trailing newline (i.e. when i == 1 or i == 2), one newline is ignored by rich.print.

A screenshot of a similar example:

(rich 3.3.2, Python 3.8.0, GNOME Terminal 3.18.3 on Linux Mint 18.2 64-bit)

[mportesdev]

Reproduced with:

rich 4.0.0 on Python 3.8.0
rich 4.0.0 on Python 3.8.3
rich 4.0.0 on Python 3.9.0b5+

[mportesdev]

Reproduced with:
rich 4.1.0 on Python 3.7.5 for Windows
rich 4.1.0 on Python 3.8.0 for Windows

[willmcgugan]

Please try v4.2.0

[mportesdev]

Looks good.

Thanks!

[mportesdev]

Btw I don't know if you use doctest in your project, but this kind of output in the interactive interpreter can be easily tested with it, e.g.:

r"""
Test examples for `rich.print`:

    >>> from rich import print
    >>> for i in range(3): print('Hey' + '\n' * i)
    ...
    Hey
    Hey
    <BLANKLINE>
    Hey
    <BLANKLINE>
    <BLANKLINE>
    >>> print('[red]Hey[/]')
    Hey
    >>> print('[red]Hey[/]\n')
    Hey
    <BLANKLINE>
    >>> print('[red]Hey[/]\n\n')
    Hey
    <BLANKLINE>
    <BLANKLINE>

"""

import doctest

if __name__ == '__main__':
    doctest.testmod()

[willmcgugan]

Might be useful occasionally, but it would be difficult to test control codes and differences across platforms with doctests.

There are tests now for this case btw.