Private identity objects are not singletons.
Nobody has claimed this yet.
Assessment
- Difficulty
- 1/5
- Estimated time
- Under an hour
- Newbie friendliness
- 55/100
- Issue type
- Documentation
- Clarity
- Clearly specified
- Activity status
- Stale
- Tech stack
- python
- Domain
- documentation
Research direction
Start with the “Support for singleton types in unions” subsection in the linked typing specification. Clarify that an object() instance is not inherently a singleton, explain why Enum is needed for singleton typing, and preserve the distinction from a private object whose identity is checked only within its module.
Written by the indexing model from the issue text.
Description
In the subsection describing singletons in unions, widely used object() example is described as a singleton, but it isn't one. It should be clearly stated that the problem for typing system is that this instance is not a singleton, that's why Enum is needed.
_empty = object() works with is check, because identity of _empty doesn't leak outside of module. There is nothing singleton about that. Typing spec can allow requiring _empty to be one, to allow use with is, but that should be clear it's the case.
- Dominant language
- Python
- Stars
- 1.8k
- Forks
- 302
- Avg merge
- 23h
- Merged PRs (30d)
- 8
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