[dataclass_transform] support implicit default for "init" parameter in field specifiers #15010
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
…n field specifiers
…py into wesleywright-field-specifier-defaults
|
According to mypy_primer, this change has no effect on the checked open source code. 🤖🎉 |
jhance
approved these changes
Apr 5, 2023
JukkaL
added a commit
that referenced
this pull request
Apr 5, 2023
…n field specifiers (#15010) (Basic functionality was implemented by @wesleywright in #14870. I added overload resolution.) This note from PEP 681 was missed in the initial implementation of field specifiers: > If unspecified, init defaults to True. Field specifier functions can use overloads that implicitly specify the value of init using a literal bool value type (Literal[False] or Literal[True]). This commit adds support for reading a default from the declared type of the `init` parameter if possible. Otherwise, it continues to use the typical default of `True`. The implementation was non-trivial, since regular overload resolution can't be used in the dataclass plugin, which is applied before type checking. As a workaround, I added a simple overload resolution helper that should be enough to support typical use cases. It doesn't do full overload resolution using types, but it knows about `None`, `Literal[True]` and `Literal[False]` and a few other things. --------- Co-authored-by: Wesley Collin Wright <[email protected]>
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
(Basic functionality was implemented by @wesleywright in #14870. I added overload resolution.)
This note from PEP 681 was missed in the initial implementation of field specifiers:
This commit adds support for reading a default from the declared type of the
initparameter if possible. Otherwise, it continues to use the typical default ofTrue.The implementation was non-trivial, since regular overload resolution can't be used in the dataclass plugin, which is applied before type checking. As a workaround, I added a simple overload resolution helper that should be enough to support typical use cases. It doesn't do full overload resolution using types, but it knows about
None,Literal[True]andLiteral[False]and a few other things.