Description

treyhunner

opened on May 6, 2024

Issue body actions

Bug report

Bug description:

I noticed that the magenta color used by the new REPL and within the non-error text in the new colorized tracebacks in 3.13 looks quite a bit like an error-related color in some popular color schemes.

Here's an image which shows how an error message displays in a few fairly popular terminal color schemes.

I've included both "bold as bright" and not.
Some terminal emulators enable that setting by default while others do not.

Here are 3 more images showing how the prompt and error messages would display if cyan, blue, or green were used instead of magenta.

A script I used to help generate those images

I couldn't find data on which color schemes are the most widely used, so I took my best guesses from a bit of research.
From the schemes I looked at (Dracula, Nord, Solarized Dark/Light, Gruvbox Dark/Light) I think Cyan, Blue, or Green would look the least like red.

I don't want to start a debate over what color to paint the bike shed, but I think the closeness of the magenta and red colors are important enough to discuss before 3.13.0 lands.

CPython versions tested on:

3.13, CPython main branch

Operating systems tested on:

Linux

Linked PRs

• gh-118626: Use less red-ish colour for non-error traceback #119966

Reacted by Serban Giuroiu, Tom Gillam and Duncan Holm

Activity

1. treyhunner

   added

   type-bugAn unexpected behavior, bug, or errorAn unexpected behavior, bug, or error

   on May 6, 2024
2. nineteendo commented on May 6, 2024

   

   nineteendo

   on May 6, 2024

   Contributor

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   Hmm, sounds more like an enhancement than a bug.
3. hugovk commented on May 6, 2024

   

   hugovk

   on May 6, 2024

   Member

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   Regarding bug/feature, I think this is something we can tweak during beta, so let's keep the bug label.

   I like the suggestion. We could keep the exception name (ZeroDivisionError) magenta/red-ish.

   For example compare GitHub's pytb highlighter:

   >>> 4 / 0
   Traceback (most recent call last):
     File "<python-input-0>", line 1, in <module>
       4 / 0
       ~~^~~
   ZeroDivisionError: division by zero

   >>> 3.to_bytes(1, 'little')"
     File "<string>", line 1
       3.to_bytes(1, 'little')
        ^
   SyntaxError: invalid decimal literal

   I think Pygments does something similar.
4. treyhunner commented on May 6, 2024

   

   treyhunner

   on May 6, 2024

   MemberAuthor

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   I like the suggestion. We could keep the exception name (ZeroDivisionError) magenta/red-ish.

   I agree that the exception name, and even the exception message, in magenta or red seems very appropriate.
5. AlexWaygood

   added

   topic-replRelated to the interactive shellRelated to the interactive shell

   on May 10, 2024
6. hugovk commented on Jun 2, 2024

   

   hugovk

   on Jun 2, 2024

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   Here's a suggestion.

   I'm trying to mirror something like GitHub's pytb colour groups to avoid having too many colours:

   >>> 4 / 0
   Traceback (most recent call last):
     File "<python-input-0>", line 1, in <module>
       4 / 0
       ~~^~~
   ZeroDivisionError: division by zero
   >>>
   >>> 3.to_bytes(1, 'little')"
     File "<string>", line 1
       3.to_bytes(1, 'little')
        ^
   SyntaxError: invalid decimal literal

   In the before and after below, I'm using macOS and have iTerm with a dark theme, and Terminal with light theme (Novel), to make it easy to compare without having to dig in the settings each time.

   Before
   After
   GitHub pytb

   What do you think?

   Reacted by Nice Zombies
7. hugovk commented on Jun 3, 2024

   

   hugovk

   on Jun 3, 2024

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   And a longer traceback using this script based on a test:

   2.py

   def foo(*args):
       x = {'a': {'b': None}}
       y = x['a']['b']['c']
   
   
   def baz2(*args):
       return (lambda *args: foo(*args))(1, 2, 3, 4)
   
   
   def baz1(*args):
       return baz2(1, 2, 3, 4)
   
   
   def bar():
       return baz1(1,
                   2, 3
                   , 4)
   
   
   bar()

   pytb

   ❯ ./python.exe 2.py
   Traceback (most recent call last):
     File "/Users/hugo/github/python/cpython/main/2.py", line 20, in <module>
       bar()
       ~~~^^
     File "/Users/hugo/github/python/cpython/main/2.py", line 15, in bar
       return baz1(1,
                   2, 3
                   , 4)
     File "/Users/hugo/github/python/cpython/main/2.py", line 11, in baz1
       return baz2(1, 2, 3, 4)
     File "/Users/hugo/github/python/cpython/main/2.py", line 7, in baz2
       return (lambda *args: foo(*args))(1, 2, 3, 4)
              ~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^
     File "/Users/hugo/github/python/cpython/main/2.py", line 7, in <lambda>
       return (lambda *args: foo(*args))(1, 2, 3, 4)
                             ~~~^^^^^^^
     File "/Users/hugo/github/python/cpython/main/2.py", line 3, in foo
       y = x['a']['b']['c']
           ~~~~~~~~~~~^^^^^
   TypeError: 'NoneType' object is not subscriptable

   Before
   After
   GitHub pytb

   Reacted by Nice Zombies
8. hugovk commented on May 4, 2025

   

   hugovk

   on May 4, 2025

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   Closing in favour of theming support: #133346
9. hugovk

   closed this as completedon May 4, 2025
10. hugovk

    closed this as a duplicateof Theming support for _colorize #133346 on May 4, 2025

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