Print \x04 and \x1a input bytes as ^D and ^Z in CliRunner

[kdeldycke]

This PR change CliRunner to translate the control bytes and render them differently on output:

<stdin> byte	Echoed to <stdout> as	Pressed keys
\x04	^D\n	Ctrl+D on Unix
\x1a	^Z\n	Ctrl+Z on Windows

It also no longer passes these bytes to the command.

As this introduce behavioral changes, it targets 8.6.0.

This will remove an hard-coded patch in pallets-sphinx-themes and a follow-up PR is maintained at pallets/pallets-sphinx-themes#133 so you can see the benefits of this change.

[davidism]

I'd prefer not to add more xyz_class style customization points, unless absolutely necessary. It makes typing more complex for anything that wants to override methods on such a class (that wouldn't really be the case here, but still). I'm actively removing them from Flask and Werkzeug.

I'm not particularly bothered by the override in the theme. I don't think enough things would want to override this to justify the new attribute.

Perhaps we should consider why the default echo doesn't show control input? Perhaps we can add it here and remove the override that way?

[kdeldycke]

why the default echo doesn't show control input? Perhaps we can add it here and remove the override that way?

Yes, I'm OK to explore that direction instead. I don't have a real use-case, just stumble upon it while cleaning my own re-implementation of the {click:*} directives for Sphinx.

Question is, should we translate all control bytes to caret-based notation or should we just do \x04, and maybe \x1a as _translate_ch_to_exc does?

click/src/click/_termui_impl.py

Lines 869 to 877 in 06b2a67

	def _translate_ch_to_exc(ch: str) -> None:
	if ch == "\x03":
	raise KeyboardInterrupt()
	if ch == "\x04" and not WIN: # Unix-like, Ctrl+D
	raise EOFError()
	if ch == "\x1a" and WIN: # Windows, Ctrl+Z
	raise EOFError()

[Rowlando13]

@kdeldycke I also think not more customization here would be good.

[kdeldycke]

Just reworked that PR and pushed it a bit: it now integrates directly the modifications from pallets-sphinx-themes, and perform the translation of bytes in CliRunner:

<stdin> byte	Echoed to <stdout> as	Pressed keys
\x04	^D\n	Ctrl+D on Unix
\x1a	^Z\n	Ctrl+Z on Windows

This does not propose a documented point of customization, but change the behavior of the CliRunner.

[kdeldycke]

Just retargeted to 8.6.0 . This PR is ready for a review.