Make the isatty method of OutStream return True

[peendebak]

The ipykernel.iostream.OutStream represents an interactive stream and should there have a isatty method returning True.
Also see #268, #680, Textualize/rich#1221

Fixes #680
Fixes #268

[blink1073]

This seems reasonable to me, thank you! I'll leave this open until Monday in case another maintainer knows of a reason not to enable this.

[real-yfprojects]

You should add Closes #680 and closes #268 .
Also thank you for creating the pull request. I didn't know this was the faster way to go.

[ccordoba12]

Although this would be quite useful to support Rich and Colorama in Spyder and the notebook, I don't know if it could have side effects on IPython's display system. I mean, there should be a reason why the OutStream is expected to behave as a TextIO object.

@minrk, @takluyver, @Carreau, what do you think?

[Carreau]

I think this is a bad idea. A lot of things assume that isatty() == True, mean you can put the terminal in raw mode and/or support cursor motion up/down to redraw previous lines.

Things like pagers ( less, more) and many others will start to misbehave if you set tty to true.

[ccordoba12]

Thanks for the input @Carreau! What if we make this change configurable then? That way, users that know what they are doing could enable this functionality for Rich and Colorama. In Spyder we could also expose this option in our Preferences system and inform users to activate it if we detect they are working with those libraries.

[dsblank]

It is too bad that there is a single flag that signals if an output can handle simple line control (like backspace), colors, and full cursor movements. We have a commercial product and almost 100% of the non-interactive output works well when istty() returns True.

[Carreau]

No objections to making in configurable..I believe there might be something like terminal/termcap that should let us hurry more in depth which capabilities the terminal has, but I don't think it's standard or has python binding.

…

On Mon, Jun 7, 2021, 20:24 Doug Blank ***@***.***> wrote: It is too bad that there is a single flag that signals if an output can handle simple line control (like backspace), colors, and full cursor movements. We have a commercial product and almost 100% of the non-interactive output works well when istty() returns True. — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#683 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AACR5T4VTLYPONL2IFBAE3TTRUFFBANCNFSM46DMXVIQ> .

[dsblank]

No objections to making in configurable

Agreed, that sounds like a good approach!

[peendebak]

@dsblank @Carreau @blink1073 @ccordoba12 I will make the option configurable, so that projects using the ipykernel can pick whichever mode they want.

The only remaining question is what the default value will be for this option. The safe option would be False. On the other hand, True might be the better option for a larger number of cases.

[ccordoba12]

The only remaining question is what the default value will be for this option. The safe option would be False. On the other hand, True might be the better option for a larger number of cases.

It needs to be False to be on the safe side and not to change the current behavior.

[peendebak]

@blink1073 The additional commits are under another github account. Could you approve the CI?

[blink1073]

Could you approve the CI?

Done!

[blink1073]

Looks like tests need updating again

[blink1073]

The linter flagged one thing: https://github.com/ipython/ipykernel/pull/683/checks?check_run_id=2777466679#step:8:21

[peendebak]

The linter flagged one thing: https://github.com/ipython/ipykernel/pull/683/checks?check_run_id=2777466679#step:8:21

@blink1073 Thanks, I fixed the formatting.

[blink1073]

Thanks for the contribution @peendebak!