Improve the default excepthook formatting for multi-line and exception notes
Aberta
Ninguém assumiu esta issue ainda.
interpreter-core
type-feature
- Linguagem predominante
- Python
- Estrelas
- 77.2k
- Forks
- 36k
- Métricas de merge de PRs
- Métricas de PR pendentes
Descrição
Proposal:
Currently, it is possible to add notes to exceptions, see BaseException.add_note, but this feature is underutilized.
One of the reasons for that, I believe, is the poor formatting in the default excepthook:
Current Output
(single note)
$ ./python
Python 3.14.0a2+ experimental free-threading build (heads/gh-127429-dirty:cc4f57a74d0, Dec 1 2024, 07:06:51) [GCC 14.2.1 20240910] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> try:
... raise Exception('error')
... except Exception as e:
... e.add_note('some context')
... raise
...
Traceback (most recent call last):
File "<python-input-0>", line 2, in <module>
raise Exception('error')
Exception: error
some context
(with multiple notes)
$ ./python
Python 3.14.0a2+ experimental free-threading build (heads/gh-127429-dirty:cc4f57a74d0, Dec 1 2024, 07:06:51) [GCC 14.2.1 20240910] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> try:
... raise Exception('error')
... except Exception as e:
... e.add_note('some context')
... e.add_note('some context 2')
... e.add_note('some context 3')
... raise
...
Traceback (most recent call last):
File "<python-input-0>", line 2, in <module>
raise Exception('error')
Exception: error
some context
some context 2
some context 3
I think if we formatted it better, making the output easier to understand, we could start seeing better adoption of this feature.
(with multiple notes)
$ ./python
Python 3.14.0a2+ experimental free-threading build (heads/gh-127429-dirty:cc4f57a74d0, Dec 1 2024, 07:06:51) [GCC 14.2.1 20240910] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> try:
... raise Exception('error')
... except Exception as e:
... e.add_note('some context')
... e.add_note('some context 2')
... e.add_note('some context 3')
... raise
...
Traceback (most recent call last):
File "<python-input-0>", line 2, in <module>
raise Exception('error')
Exception: error
├── Note: some context
├── Note: some context 2
└── Note: some context 3
In addition to this, multiline exception messages could also be improved.
Current Output
(multi-line string, with no notes)
$./python
Python 3.14.0a2+ experimental free-threading build (heads/gh-127429-dirty:cc4f57a74d0, Dec 1 2024, 07:06:51) [GCC 14.2.1 20240910] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> raise Exception('some error\n\nsome context\nsome context (cont.)\n\nsome extra context')
Traceback (most recent call last):
File "<python-input-0>", line 1, in <module>
raise Exception('some error\n\nsome context\nsome context (cont.)\n\nsome extra context')
Exception: some error
some context
some context (cont.)
some extra context
(multi-line string, with multi-line notes)
$ ./python
Python 3.14.0a2+ experimental free-threading build (heads/gh-127429-dirty:cc4f57a74d0, Dec 1 2024, 07:06:51) [GCC 14.2.1 20240910] on linux
>>> try:
... raise Exception('some error\n\nsome error text\nsome error text (cont.)\n\nsome more error text')
... except Exception as e:
... e.add_note('some context\nsome context (cont.)')
... e.add_note('some context 2\n\nsome extra context 2')
... e.add_note('some context 3\nsome context 3 (cont.)\n\nsome extra context 3')
... raise
...
Traceback (most recent call last):
File "<python-input-0>", line 2, in <module>
raise Exception('some error\n\nsome error text\nsome error text (cont.)\n\nsome more error text')
Exception: some error
some error text
some error text (cont.)
some more error text
some context
some context (cont.)
some context 2
some extra context 2
some context 3
some context 3 (cont.)
some extra context 3
The first example IMO isn't optimal, but it's okay enough, but the second example is very confusing. We could format it something like:
$ ./python
Python 3.14.0a2+ experimental free-threading build (heads/gh-127429-dirty:cc4f57a74d0, Dec 1 2024, 07:06:51) [GCC 14.2.1 20240910] on linux
>>> try:
... raise Exception('some error\n\nsome error text\nsome error text (cont.)\n\nsome more error text')
... except Exception as e:
... e.add_note('some context\nsome context (cont.)')
... e.add_note('some context 2\n\nsome extra context 2')
... e.add_note('some context 3\nsome context 3 (cont.)\n\nsome extra context 3')
... raise
...
Traceback (most recent call last):
File "<python-input-0>", line 2, in <module>
raise Exception('some error\n\nsome error text\nsome error text (cont.)\n\nsome more error text')
Exception:
│ │ some error
│ │
│ │ some error text
│ │ some error text (cont.)
│ │
│ └ some more error text
│
├── Note:
│ │ some context
│ └ some context (cont.)
│
├── Note:
│ │ some context 2
│ │
│ └ some extra context 2
│
└── Note:
│ some context 3
│ some context 3 (cont.)
│
└ some extra context 3
Has this already been discussed elsewhere?
No response given
Links to previous discussion of this feature:
No response
Guia de contribuição
Primeiros passos
- Leia a issue inteira e depois o guia de contribuição do projeto.
- Comente na issue dizendo que vai assumir — evita que duas pessoas façam o mesmo trabalho.
- Faça um fork do repositório e trabalhe em uma branch.
- Abra um pull request que referencie o número da issue.
Direção de pesquisa
Comece pelos pontos de entrada padrão do CPython para excepthook e formatação de exceções; a issue não nomeia um arquivo nem um teste. Compare a saída atual com os exemplos propostos de notas de uma linha e de várias linhas e considere concluído quando a formatação em árvore pretendida for obtida sem perder o conteúdo da mensagem.
Escrita pelo modelo de indexação a partir do texto da issue.
Avaliação
- Stack de tecnologia
- python
- Domínio
- backend
- Tipo de issue
- Funcionalidade
- Dificuldade
- 5/5
- Tempo estimado
- Mais de uma semana
- Status de atividade
- Estagnada
- Clareza
- Razoavelmente clara
- Facilidade para iniciantes
- 35/100