🚸 Expose PydanticUndefinedType

[Kludex]

Change Summary

The goal here is to expose the PydanticUndefinedType. I'm unsure if this is the best way to do it.

The motivation is that FastAPI wants the type of PydanticUndefined, and I can't get that since PydanticUndefined is an object(). See FastAPI code for more details.

Checklist

• Unit tests for the changes exist
• Documentation reflects the changes where applicable
• Pydantic tests pass with this pydantic-core (except for expected changes)
• My PR is ready to review, please add a comment including the phrase "please review" to assign reviewers

Selected Reviewer: @davidhewitt

[Kludex]

please review

[codecov-commenter]

Codecov Report

Merging #693 (7bb97b9) into main (4c2a8f8) will increase coverage by 0.00%.
The diff coverage is 100.00%.

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Additional details and impacted files

@@           Coverage Diff           @@
##             main     #693   +/-   ##
=======================================
  Coverage   93.72%   93.72%           
=======================================
  Files          99       99           
  Lines       13804    13805    +1     
  Branches       25       25           
=======================================
+ Hits        12938    12939    +1     
  Misses        860      860           
  Partials        6        6           

Impacted Files	Coverage Δ
pydantic_core/__init__.py	81.81% <ø> (ø)
src/argument_markers.rs	86.88% <100.00%> (ø)
src/lib.rs	100.00% <100.00%> (ø)
src/validators/model.rs	98.41% <100.00%> (ø)
src/validators/with_default.rs	99.10% <100.00%> (ø)

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[codspeed-hq]

CodSpeed Performance Report

Merging #693 feat/add-PydanticUndefinedType (7bb97b9) will improve performances by 10.2%.

Summary

🔥 1 improvements
❌ 0 regressions
✅ 124 untouched benchmarks

🆕 0 new benchmarks
⁉️ 0 dropped benchmarks

Benchmarks breakdown

	Benchmark	main	feat/add-PydanticUndefinedType	Change
🔥	test_small_class_core_model	59 µs	53.5 µs	+10.2%

[davidhewitt]

Looks good to me 👍

[Kludex]

Ha! My first PR in rust. 😎