model_json_schema export with Annotated types misses 'required' parameters

[LouisGobert]

Change Summary

When using an Annotation with a FieldInfo and an Ellipsis, the Ellipsis was considered as a default value. Therefore, the field was not considered mandatory.

Related issue number

fix #8780
fix #8634

Checklist

• The pull request title is a good summary of the changes - it will be used in the changelog
• Unit tests for the changes exist
• Tests pass on CI
• Documentation reflects the changes where applicable
• My PR is ready to review, please add a comment including the phrase "please review" to assign reviewers

Selected Reviewer: @lig

[codspeed-hq]

CodSpeed Performance Report

Merging #8793 will not alter performance

_{Comparing LouisGobert:fix-annotation-with-field (093d05c) with main (832225b)}

Summary

✅ 10 untouched benchmarks

[LouisGobert]

please review

First open source contribution 🤞

[sydney-runkle]

Looks great overall, just 2 quick change requests. Thanks!

[sydney-runkle]

Suggested change

	"""Check if the ellipsis in the signature is considered as a required field."""
	"""Ensure field specified with Annotated in create_model call is still marked as required."""

[sydney-runkle]

Could you include this example as well? baz=(Annotated[int, Field(..., description="Baz description")], ...),

[sydney-runkle]

Maybe with this model:

Model = create_model(
    'test_model',
    foo=(int, ...),
    bar=(Annotated[int, Field(description="Bar description")], ...),
    baz=(Annotated[int, Field(..., description="Baz description")], ...),
)

[LouisGobert]

Done 😄

[sydney-runkle]

So, with a slight modification to the logic in your PR, we can actually fix many related issues. My proposal is the following:

diff --git a/pydantic/fields.py b/pydantic/fields.py
index e369b52d..58332d79 100644
--- a/pydantic/fields.py
+++ b/pydantic/fields.py
@@ -402,6 +402,13 @@ class FieldInfo(_repr.Representation):
             # No merging necessary, but we still need to make a copy and apply the overrides
             field_info = copy(field_infos[0])
             field_info._attributes_set.update(overrides)
+
+            default_override = overrides.pop('default', PydanticUndefined)
+            if default_override is Ellipsis:
+                default_override = PydanticUndefined
+            if field_info.default is not PydanticUndefined and default_override is not PydanticUndefined:
+                field_info.default = default_override
+
             for k, v in overrides.items():
                 setattr(field_info, k, v)
             return field_info  # type: ignore

Which fixes:

• model_json_schema export with Annotated types misses 'required' parameters #8780 (the original issue for which you started on a fix)
• Ellipsis does not mark annotated field as required in create_model #8634

Would you be willing to add a test for the second issue as well? Thanks for your contribution!

[LouisGobert]

if field_info.default is not PydanticUndefined and default_override is not PydanticUndefined:
    field_info.default = default_override

I think this was the wrong proposal because if a field is initialized with a default = PydanticUndefined, the overide won't work 😄

My modification:

if default_override is not PydanticUndefined:
    field_info.default = default_override

[sydney-runkle]

Looks great, thanks for the help with the fix!