Move pattern specification for BaseType.identifier to the annotation for the str type

[candleindark]

My guess of the intention for BaseType.identifier is an object either validates to an AnyHttpUrl or a str matching the pattern of r"^[a-zA-Z0-9-]+:[a-zA-Z0-9-/\._]+$". If my guess is correct, the type annotation should be corrected to the proposed change in this PR.

The current type annotation of BaseType.identifier has problems exhibited by the Foo.identifier from the following example (Baz.identifier exhibits the solution proposed by this PR).

from typing import Optional, Union
import json

from typing_extensions import Annotated

from pydantic import BaseModel, Field, AnyHttpUrl, StringConstraints, ValidationError

PATTERN = r"^[a-zA-Z0-9-]+:[a-zA-Z0-9-/\._]+$"


class Foo(BaseModel):
    identifier: Optional[Union[AnyHttpUrl, str]] = Field(None, pattern=PATTERN)


class Bar(BaseModel):
    identifier: Optional[
        Union[AnyHttpUrl, Annotated[str, StringConstraints(pattern=PATTERN)]]
    ] = None


class Baz(BaseModel):
    identifier: Optional[
        Annotated[
            Union[AnyHttpUrl, Annotated[str, StringConstraints(pattern=PATTERN)]],
            Field(union_mode="left_to_right"),
        ]
    ] = None

# Try inputting an AnyHttpUrl object
print("======= Interation 0 =======")
try:
    foo0 = Foo(identifier=AnyHttpUrl("https://example.com"))
except ValidationError as e:
    print(e)
    """
    1 validation error for Foo
    identifier
      Input should be a valid string [type=string_type, input_value=Url('https://example.com/'), input_type=Url]
        For further information visit https://errors.pydantic.dev/2.7/v/string_type
    """
else:
    raise RuntimeError("Expected a validation error")

bar0 = Bar(identifier=AnyHttpUrl("https://example.com"))
baz0 = Baz(identifier=AnyHttpUrl("https://example.com"))

# Try inputting a string object
print("\n======= Interation 1 =======")
try:
    foo1 = Foo(identifier="https://www.python.org/~guido?arg=1#frag")
except ValidationError as e:
    print(e)
    """
    1 validation error for Foo
    identifier
      String should match pattern '^[a-zA-Z0-9-]+:[a-zA-Z0-9-/\._]+$' [type=string_pattern_mismatch, input_value='https://www.python.org/~guido?arg=1#frag', input_type=str]
        For further information visit https://errors.pydantic.dev/2.7/v/string_pattern_mismatch
    """
else:
    raise RuntimeError("Expected a validation error")

bar1 = Bar(identifier="https://www.python.org/~guido?arg=1#frag")
print(f"type(bar1.identifier): {type(bar1.identifier)}")
"""type(bar1.identifier): <class 'pydantic_core._pydantic_core.Url'>"""

baz1 = Baz(identifier="https://www.python.org/~guido?arg=1#frag")
print(f"type(baz1.identifier): {type(baz1.identifier)}")
"""type(baz1.identifier): <class 'pydantic_core._pydantic_core.Url'>"""

# Try inputting a string object that are simple
print("\n======= Interation 2 =======")
bar2 = Bar(identifier="https://example.com")
print(f"type(bar2.identifier): {type(bar2.identifier)}")
"""type(bar2.identifier): <class 'str'>"""

baz2 = Baz(identifier="https://example.com")
print(f"type(baz2.identifier): {type(baz2.identifier)}")
"""type(baz2.identifier): <class 'pydantic_core._pydantic_core.Url'>"""

Essentially, the current annotation fails to validate any AnyHttpUrl object and any HTTP URL, as a str, that contains a special character.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 91.83%. Comparing base (be57e13) to head (2fdc912).

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Flag	BASE (be57e13)	HEAD (2fdc912)
unittests	151	30

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #247      +/-   ##
==========================================
- Coverage   97.74%   91.83%   -5.91%     
==========================================
  Files          16       16              
  Lines        1727     1727              
==========================================
- Hits         1688     1586     -102     
- Misses         39      141     +102     

Flag	Coverage Δ
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