fix: allow non canonical values for Enums

Author: azmeuk

doc/changelog.rst

@@ -1,6 +1,13 @@
 Changelog
 =========
 
+[0.4.3] - Unreleased
+--------------------
+
+Fixed
+^^^^^
+- Allow non canonical values for enums. :issue:`34`
+
 [0.4.2] - 2025-08-05
 --------------------
 

scim2_models/attributes.py

@@ -1,9 +1,15 @@
+from enum import Enum
 from inspect import isclass
 from typing import Annotated
 from typing import Any
 from typing import Optional
 from typing import get_origin
 
+try:
+    from typing import Self
+except ImportError:
+    from typing_extensions import Self
+
 from pydantic import Field
 
 from .annotations import Mutability
@@ -13,6 +19,35 @@
 from .reference import Reference
 
 
+class ExtensibleStringEnum(str, Enum):
+    """String enum that accepts arbitrary values while preserving canonical ones.
+
+    This enum allows both predefined canonical values and arbitrary string values,
+    conforming to :rfc:`RFC 7643 <7643>` which permits service providers to accept
+    additional type values beyond the recommended set.
+    """
+
+    def __str__(self) -> str:
+        """Return just the string value, not the enum representation."""
+        return str(self.value)
+
+    @classmethod
+    def _missing_(cls, value: Any) -> Self:
+        """Handle unknown enum values by creating dynamic instances.
+
+        :param value: The value to create an enum instance for
+        :return: A new enum instance for the given value
+        :raises ValueError: If value is not a string
+        """
+        if isinstance(value, str):
+            # Create a pseudo enum member for unknown string values
+            obj = str.__new__(cls, value)
+            obj._name_ = value
+            obj._value_ = value
+            return obj
+        raise ValueError(f"{value} is not a valid string value for {cls.__name__}")
+
+
 class ComplexAttribute(BaseModel):
     """A complex attribute as defined in :rfc:`RFC7643 §2.3.8 <7643#section-2.3.8>`."""
 

scim2_models/resources/user.py

@@ -1,4 +1,3 @@
-from enum import Enum
 from typing import Annotated
 from typing import ClassVar
 from typing import Literal
@@ -14,6 +13,7 @@
 from ..annotations import Returned
 from ..annotations import Uniqueness
 from ..attributes import ComplexAttribute
+from ..attributes import ExtensibleStringEnum
 from ..attributes import MultiValuedComplexAttribute
 from ..reference import ExternalReference
 from ..reference import Reference
@@ -49,7 +49,7 @@ class Name(ComplexAttribute):
 
 
 class Email(MultiValuedComplexAttribute):
-    class Type(str, Enum):
+    class Type(ExtensibleStringEnum):
         work = "work"
         home = "home"
         other = "other"
@@ -70,7 +70,7 @@ class Type(str, Enum):
 
 
 class PhoneNumber(MultiValuedComplexAttribute):
-    class Type(str, Enum):
+    class Type(ExtensibleStringEnum):
         work = "work"
         home = "home"
         mobile = "mobile"
@@ -97,7 +97,7 @@ class Type(str, Enum):
 
 
 class Im(MultiValuedComplexAttribute):
-    class Type(str, Enum):
+    class Type(ExtensibleStringEnum):
         aim = "aim"
         gtalk = "gtalk"
         icq = "icq"
@@ -125,7 +125,7 @@ class Type(str, Enum):
 
 
 class Photo(MultiValuedComplexAttribute):
-    class Type(str, Enum):
+    class Type(ExtensibleStringEnum):
         photo = "photo"
         thumbnail = "thumbnail"
 
@@ -145,7 +145,7 @@ class Type(str, Enum):
 
 
 class Address(MultiValuedComplexAttribute):
-    class Type(str, Enum):
+    class Type(ExtensibleStringEnum):
         work = "work"
         home = "home"
         other = "other"

tests/test_user.py

@@ -1,12 +1,15 @@
 import datetime
 
+import pytest
+
 from scim2_models import Address
 from scim2_models import Email
 from scim2_models import Im
 from scim2_models import PhoneNumber
 from scim2_models import Photo
 from scim2_models import Reference
 from scim2_models import User
+from scim2_models.attributes import ExtensibleStringEnum
 
 
 def test_minimal_user(load_sample):
@@ -124,3 +127,64 @@ def test_full_user(load_sample):
         obj.meta.location
         == "https://example.com/v2/Users/2819c223-7f76-453a-919d-413861904646"
     )
+
+
+def test_extensible_enum_canonical_values():
+    """Test that canonical enum values work as expected."""
+
+    class TestEnum(ExtensibleStringEnum):
+        foo = "foo"
+        bar = "bar"
+
+    assert TestEnum.foo == "foo"
+    assert TestEnum.bar == "bar"
+    assert str(TestEnum.foo) == "foo"
+
+
+def test_extensible_enum_arbitrary_values():
+    """Test that arbitrary string values are accepted."""
+
+    class TestEnum(ExtensibleStringEnum):
+        foo = "foo"
+        bar = "bar"
+
+    # Create instances with arbitrary values
+    custom = TestEnum("custom_value")
+    another = TestEnum("another_value")
+
+    assert str(custom) == "custom_value"
+    assert str(another) == "another_value"
+    assert custom == "custom_value"
+    assert another == "another_value"
+
+
+def test_extensible_enum_non_string_rejected():
+    """Test that non-string values are rejected."""
+
+    class TestEnum(ExtensibleStringEnum):
+        foo = "foo"
+
+    with pytest.raises(ValueError, match="is not a valid string value"):
+        TestEnum(123)
+
+    with pytest.raises(ValueError, match="is not a valid string value"):
+        TestEnum(None)
+
+
+def test_complex_attribute_extensible_types():
+    """Test that complex attribute types support RFC 7643 extensibility."""
+    # Test with Email - canonical and arbitrary types
+    email_canonical = Email(value="[email protected]", type=Email.Type.work)
+    assert str(email_canonical.type) == "work"
+
+    email_custom = Email(value="[email protected]", type="company")  # Issue #34 case
+    assert str(email_custom.type) == "company"
+
+    # Test serialization works correctly
+    data = email_custom.model_dump()
+    assert data["type"] == "company"
+
+    # Test round-trip serialization
+    restored = Email.model_validate(data)
+    assert str(restored.type) == "company"
+    assert restored.value == "[email protected]"