Styled output support for JupyterLab

[munael]

Not sure if this's a goal. But some issues mention support for Jupyter Notebook, and I'm not sure why it doesn't work in Jupyter Lab. It prints fine, but with no styling.

• Python 3.7.1
• Click 7.0
• Jupyter Lab 0.35.4

[davidism]

duplicate of #1186

[RonnyPfannschmidt]

based on the comment in #1186 this one has to reopen as its a different kernel with a different io stream

[awalvie]

I have successfully duplicated the issue on JupyterLab in Windows:
Input:

import click

print(click.style('Hello World!', fg='green', bold=True, underline=True))
click.echo(click.style('Hello World!', fg='green', bold=True, underline=True))
click.echo(click.style('ATTENTION!', blink=True))
click.echo(click.style('Some things', reverse=True, fg='cyan'))

Output:

So we don't have any styling whatsoever here, which is expected.
Interestingly enough I found another inconsistency that's not just limited to JupyterLab, passing the same input into a test file gives us the following result.

Using print leads to the expected style, with bold and underline, whereas using click.echo does not enable them.
This was pointed out in the following comment -> #1186 (comment)

[davidism]

You'll have to be more specific about how you're writing to a file for me to say, but at least the print behavior is expected. click.echo checks the stream to see if it should strip the color codes, print does not. That's the whole issue, there's a special check to tell it that Jupyter kernel streams are ok, but it still doesn't detect JupyterLab streams.

[awalvie]

Roger that! I'll get right on it, thanks for the clarification.