[BUG] [Windows] ANSI SGR sequences printed to streams which are not attached to TTYs.

[emcd]

• I've checked docs and closed issues for possible solutions.
• I can't find my issue in the FAQ.

Describe the bug

On Windows, ANSI SGR sequences are emitted regardless of whether a stream is attached to a TTY or not.
The following simple reproducer will correctly print an uncolored "foo" on non-Windows platforms but will print a red "foo" on Windows:

from locale import getpreferredencoding
from os import devnull
from rich.console import Console
from rich.style import Style

blackhole = open( devnull, 'w', encoding = getpreferredencoding( ) )
console = Console( file = blackhole )
with console.capture( ) as capture:
    console.print( 'foo', style = Style( color = 'red' ) )

# Prints plain 'foo' on non-Windows; prints red 'foo' on Windows.
# Should print plain 'foo' on all platforms.
print( capture.get( ) )

The null device is definitely not a TTY, but capture on a Console print will show that ANSI C1 sequences are being emitted.

Expected behavior is that a plain "foo" would be printed on all platforms.

Closely related to #3647. (And maybe fixed by #3648, though it is not clear that the terminal on the Github Actions Windows runners is a legacy terminal. But, it seems like the code path for legacy terminal detection is not different than that for non-terminal detection on Windows, so the fix may be valid. Would definitely like to see the fix or a maintainer-approved variant thereof merged.)

Possibly has some bearing on #2622 and #3082, even though they are the "opposite" problem.

Platforms

Platform 1: (exhibits bug)

Windows 10, CMD.EXE
╭────────────────────────────────────────────────────────────────────────────────────────────────────────────────────── <class 'rich.console.Console'> ──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────╮
│ A high level console interface. │
│ │
│ ╭────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────╮ │
│ │ │ │
│ ╰────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────╯ │
│ │
│ color_system = 'truecolor' │
│ encoding = 'utf-8' │
│ file = <_io.TextIOWrapper name='' mode='w' encoding='utf-8'> │
│ height = 76 │
│ is_alt_screen = False │
│ is_dumb_terminal = False │
│ is_interactive = True │
│ is_jupyter = False │
│ is_terminal = True │
│ legacy_windows = False │
│ no_color = False │
│ options = ConsoleOptions(size=ConsoleDimensions(width=270, height=76), legacy_windows=False, min_width=1, max_width=270, is_terminal=True, encoding='utf-8', max_height=76, justify=None, overflow=None, no_wrap=False, highlight=None, markup=None, height=None) │
│ quiet = False │
│ record = False │
│ safe_box = True │
│ size = ConsoleDimensions(width=270, height=76) │
│ soft_wrap = False │
│ stderr = False │
│ style = None │
│ tab_size = 8 │
│ width = 270 │
╰────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────╯
╭── <class 'rich._windows.WindowsConsoleFeatures'> ───╮
│ Windows features available. │
│ │
│ ╭─────────────────────────────────────────────────╮ │
│ │ WindowsConsoleFeatures(vt=True, truecolor=True) │ │
│ ╰─────────────────────────────────────────────────╯ │
│ │
│ truecolor = True │
│ vt = True │
╰─────────────────────────────────────────────────────╯
╭─────────────────────────────────────────────────────────────────────────────────────────────────────────────────── Environment Variables ───────────────────────────────────────────────────────────────────────────────────────────────────────────────────╮
│ {'CLICOLOR': None, 'COLORTERM': None, 'COLUMNS': None, 'JPY_PARENT_PID': None, 'JUPYTER_COLUMNS': None, 'JUPYTER_LINES': None, 'LINES': None, 'NO_COLOR': None, 'TERM_PROGRAM': None, 'TERM': None, 'TTY_COMPATIBLE': None, 'VSCODE_VERBOSE_LOGGING': None} │
╰─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────╯
platform="Windows"

rich==14.0.0

Platform 2: (exhibits bug)

Github Actions Windows runner (Windows 11?), Git Bash (mintty)?

Platform 3: (does not exhibit bug)

Ubuntu 22.04 (GNU/Linux)

[github-actions]

Thank you for your issue. Give us a little time to review it.

PS. You might want to check the FAQ if you haven't done so already.

This is an automated reply, generated by FAQtory

[xymy]

I think your issue is not related to #3647. In your code, blackhole.isatty() is True, which leads to console.is_terminal is True. So rich will not strip ANSI code.

Try to open a random file, and it does not print ANSI color code any more:

from locale import getpreferredencoding
from os import devnull
from rich.console import Console
from rich.style import Style

# Change filename to 'foo'
blackhole = open( 'foo', 'w', encoding = getpreferredencoding( ) )
console = Console( file = blackhole )
with console.capture( ) as capture:
    console.print( 'foo', style = Style( color = 'red' ) )

# Does not print ANSI color code any more
print( capture.get( ) )

[emcd]

I think your issue is not related to #3647. In your code, blackhole.isatty() is True,

The null device is not a TTY on POSIX systems:

>>> sys.platform
'linux'
>>> f = open( os.devnull, 'w' )
>>> f.isatty( )
False

However, you appear to be correct about the behavior on Windows:

>>> sys.platform
'win32'
>>> f = open( os.devnull, 'w' )
>>> f.isatty( )
True

That is very unintuitive. Will withdraw this issue. Thanks for the followup.

[github-actions]

I hope we solved your problem.

If you like using Rich, you might also enjoy Textual