feat: Support string[] as condition value for the IN operator

Author: khvn26

flag_engine/context/types.py

@@ -1,10 +1,10 @@
 # generated by datamodel-codegen:
-#   filename:  https://raw.githubusercontent.com/Flagsmith/flagsmith/chore/features-contexts-in-eval-context-schema/sdk/evaluation-context.json  # noqa: E501
-#   timestamp: 2025-08-11T18:17:29+00:00
+#   filename:  https://raw.githubusercontent.com/Flagsmith/flagsmith/chore/support-str-array-for-in-condition/sdk/evaluation-context.json
+#   timestamp: 2025-08-25T11:10:31+00:00
 
 from __future__ import annotations
 
-from typing import Any, Dict, List, Optional, TypedDict, Union
+from typing import Any, Dict, List, Literal, Optional, TypedDict, Union
 
 from typing_extensions import NotRequired
 
@@ -27,12 +27,21 @@ class IdentityContext(TypedDict):
     traits: NotRequired[Dict[str, Optional[Union[str, float, bool]]]]
 
 
-class SegmentCondition(TypedDict):
-    property: NotRequired[str]
+class SegmentCondition1(TypedDict):
+    property: str
     operator: ConditionOperator
     value: str
 
 
+class SegmentCondition2(TypedDict):
+    property: str
+    operator: Literal["IN"]
+    value: List[str]
+
+
+SegmentCondition = Union[SegmentCondition1, SegmentCondition2]
+
+
 class SegmentRule(TypedDict):
     type: RuleType
     conditions: NotRequired[List[SegmentCondition]]

flag_engine/segments/evaluator.py

@@ -17,6 +17,7 @@
     SegmentContext,
     SegmentRule,
 )
+from flag_engine.context.types import SegmentCondition1 as StrValueSegmentCondition
 from flag_engine.environments.models import EnvironmentModel
 from flag_engine.identities.models import IdentityModel
 from flag_engine.identities.traits.types import ContextValue, is_trait_value
@@ -235,6 +236,29 @@ def context_matches_condition(
         else None
     )
 
+    if condition["operator"] == constants.IN:
+        if isinstance(segment_value := condition["value"], list):
+            in_values = segment_value
+        else:
+            try:
+                in_values = json.loads(segment_value)
+                # Only accept JSON lists.
+                # Ideally, we should use something like pydantic.TypeAdapter[list[str]],
+                # but we aim to ditch the pydantic dependency in the future.
+                if not isinstance(in_values, list):
+                    raise ValueError
+            except ValueError:
+                in_values = segment_value.split(",")
+        in_values = [str(value) for value in in_values]
+        # Guard against comparing boolean values to numeric strings.
+        if isinstance(context_value, int) and not any(
+            context_value is x for x in (False, True)
+        ):
+            context_value = str(context_value)
+        return context_value in in_values
+
+    condition = typing.cast(StrValueSegmentCondition, condition)
+
     if condition["operator"] == constants.PERCENTAGE_SPLIT:
         if context_value is not None:
             object_ids = [segment_key, context_value]
@@ -270,7 +294,7 @@ def get_context_value(
 
 
 def _matches_context_value(
-    condition: SegmentCondition,
+    condition: StrValueSegmentCondition,
     context_value: ContextValue,
 ) -> bool:
     if matcher := MATCHERS_BY_OPERATOR.get(condition["operator"]):
@@ -316,29 +340,6 @@ def _evaluate_modulo(
     return context_value % divisor == remainder
 
 
-def _evaluate_in(
-    segment_value: typing.Optional[str], context_value: ContextValue
-) -> bool:
-    if segment_value:
-        try:
-            in_values = json.loads(segment_value)
-            # Only accept JSON lists.
-            # Ideally, we should use something like pydantic.TypeAdapter[list[str]],
-            # but we aim to ditch the pydantic dependency in the future.
-            if not isinstance(in_values, list):
-                raise ValueError
-            in_values = [str(value) for value in in_values]
-        except ValueError:
-            in_values = segment_value.split(",")
-        # Guard against comparing boolean values to numeric strings.
-        if isinstance(context_value, int) and not any(
-            context_value is x for x in (False, True)
-        ):
-            context_value = str(context_value)
-        return context_value in in_values
-    return False
-
-
 def _context_value_typed(
     func: typing.Callable[..., bool],
 ) -> typing.Callable[[typing.Optional[str], ContextValue], bool]:
@@ -365,7 +366,6 @@ def inner(
     constants.NOT_CONTAINS: _evaluate_not_contains,
     constants.REGEX: _evaluate_regex,
     constants.MODULO: _evaluate_modulo,
-    constants.IN: _evaluate_in,
     constants.EQUAL: _context_value_typed(operator.eq),
     constants.GREATER_THAN: _context_value_typed(operator.gt),
     constants.GREATER_THAN_INCLUSIVE: _context_value_typed(operator.ge),

tests/unit/segments/fixtures.py

@@ -1,4 +1,4 @@
-from flag_engine.context.types import SegmentCondition, SegmentContext, SegmentRule
+from flag_engine.context.types import SegmentContext, SegmentRule
 from flag_engine.segments import constants
 
 trait_key_1 = "email"
@@ -19,7 +19,7 @@
         SegmentRule(
             type=constants.ALL_RULE,
             conditions=[
-                SegmentCondition(
+                dict(
                     operator=constants.EQUAL,
                     property=trait_key_1,
                     value=trait_value_1,
@@ -36,12 +36,12 @@
         SegmentRule(
             type=constants.ALL_RULE,
             conditions=[
-                SegmentCondition(
+                dict(
                     operator=constants.EQUAL,
                     property=trait_key_1,
                     value=trait_value_1,
                 ),
-                SegmentCondition(
+                dict(
                     operator=constants.EQUAL,
                     property=trait_key_2,
                     value=trait_value_2,
@@ -58,12 +58,12 @@
         SegmentRule(
             type=constants.ANY_RULE,
             conditions=[
-                SegmentCondition(
+                dict(
                     operator=constants.EQUAL,
                     property=trait_key_1,
                     value=trait_value_1,
                 ),
-                SegmentCondition(
+                dict(
                     operator=constants.EQUAL,
                     property=trait_key_2,
                     value=trait_value_2,
@@ -83,12 +83,12 @@
                 SegmentRule(
                     type=constants.ALL_RULE,
                     conditions=[
-                        SegmentCondition(
+                        dict(
                             operator=constants.EQUAL,
                             property=trait_key_1,
                             value=trait_value_1,
                         ),
-                        SegmentCondition(
+                        dict(
                             operator=constants.EQUAL,
                             property=trait_key_2,
                             value=trait_value_2,
@@ -98,7 +98,7 @@
                 SegmentRule(
                     type=constants.ALL_RULE,
                     conditions=[
-                        SegmentCondition(
+                        dict(
                             operator=constants.EQUAL,
                             property=trait_key_3,
                             value=trait_value_3,
@@ -117,7 +117,7 @@
         SegmentRule(
             type=constants.ALL_RULE,
             conditions=[
-                SegmentCondition(
+                dict(
                     operator=constants.EQUAL,
                     property=trait_key_1,
                     value=trait_value_1,
@@ -127,7 +127,7 @@
                 SegmentRule(
                     type=constants.ALL_RULE,
                     conditions=[
-                        SegmentCondition(
+                        dict(
                             operator=constants.EQUAL,
                             property=trait_key_2,
                             value=trait_value_2,
@@ -137,7 +137,7 @@
                 SegmentRule(
                     type=constants.ALL_RULE,
                     conditions=[
-                        SegmentCondition(
+                        dict(
                             operator=constants.EQUAL,
                             property=trait_key_3,
                             value=trait_value_3,