Empty values of FORCE_COLOR and NO_COLOR are not ignored

[serhiy-storchaka]

Bug report

Bug description:

https://no-color.org/

Command-line software which adds ANSI color to its output by default should check for a NO_COLOR environment variable that, when present and not an empty string (regardless of its value), prevents the addition of ANSI color.

https://force-color.org/

Command-line software which outputs colored text should check for a FORCE_COLOR environment variable. When this variable is present and not an empty string (regardless of its value), it should force the addition of ANSI color.

Both "standards" state that these environment variables has only effect if their value is not an empty string. But Python currently only tests that the environment variables are defined.

CPython versions tested on:

CPython main branch

Operating systems tested on:

Linux

Linked PRs

• gh-129061: Fix FORCE_COLOR and NO_COLOR when empty strings #129140
• [3.13] gh-129061: Fix FORCE_COLOR and NO_COLOR when empty strings (GH-129140) #129360

[serhiy-storchaka]

cc @hugovk

[erlend-aasland]

See also earlier discussion: #128318 (comment)

[hugovk]

Please see PR #129140.