René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"`can_colorize()` ignores `FORCE_COLOR`/`NO_COLOR`/`TERM` when `-E` is set","articleBody":"# Bug report\r\n\r\n### Bug description:\r\n\r\nUsing one of the `FORCE_COLOR`, `NO_COLOR` or `TERM=dumb` environment variables is ignored when you use Python with `-E`.\r\n\r\n* https://docs.python.org/3/using/cmdline.html#using-on-controlling-color\r\n\r\n`-E` means:\r\n\r\n\u003e Ignore all `PYTHON*` environment variables, e.g. [PYTHONPATH](https://docs.python.org/3/using/cmdline.html#envvar-PYTHONPATH) and [PYTHONHOME](https://docs.python.org/3/using/cmdline.html#envvar-PYTHONHOME), that might be set.\r\n\r\n* https://docs.python.org/3/using/cmdline.html#cmdoption-E\r\n\r\nThe `-E` is stored in `sys.flags.ignore_environment`.\r\n\r\n* https://docs.python.org/3/library/sys.html#sys.flags.ignore_environment\r\n\r\n`sys.flags.ignore_environment` is used to ignore `PYTHON_COLORS` (correct) but it's also ignoring these other env vars (incorrect).\r\n\r\nFor example, this is not colourised, as expected:\r\n\r\n```\r\n❯ NO_COLOR=1 python3.13 -c 1/0\r\nTraceback (most recent call last):\r\n  File \"\u003cstring\u003e\", line 1, in \u003cmodule\u003e\r\n    1/0\r\n    ~^~\r\nZeroDivisionError: division by zero\r\n```\r\n\r\n![image](https://github.com/user-attachments/assets/c33675fa-ee7b-4233-8ba8-4682f4ebe4d8)\r\n\r\nHowever, `NO_COLOR=1` is ignored when passing `-E` and the output has colour when it should not:\r\n\r\n```\r\n❯ NO_COLOR=1 python3.13 -E -c 1/0\r\nTraceback (most recent call last):\r\n  File \"\u003cstring\u003e\", line 1, in \u003cmodule\u003e\r\n    1/0\r\n    ~^~\r\nZeroDivisionError: division by zero\r\n```\r\n\r\n![image](https://github.com/user-attachments/assets/263cac4f-b891-4ff2-948b-f7beaa9646ba)\r\n\r\n\r\nThis bit needs updating:\r\n\r\nhttps://github.com/python/cpython/blob/487fdbed40734fd7721457c6f6ffeca03da0b0e7/Lib/_colorize.py#L43-L56\r\n\r\n\r\n### CPython versions tested on:\r\n\r\n3.13, 3.14\r\n\r\n### Operating systems tested on:\r\n\r\nLinux, macOS, Windows\n\n\u003c!-- gh-linked-prs --\u003e\n### Linked PRs\n* gh-127877\n* gh-129138\n\u003c!-- /gh-linked-prs --\u003e\n","author":{"url":"https://github.com/hugovk","@type":"Person","name":"hugovk"},"datePublished":"2024-12-12T16:23:38.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":0},"url":"https://github.com/127873/cpython/issues/127873"}