avoid mutating input

Author: khvn26

flag_engine/segments/evaluator.py

@@ -6,6 +6,7 @@
 import typing
 import warnings
 from contextlib import suppress
+from copy import deepcopy
 from functools import lru_cache, partial, wraps
 
 import jsonpath_rfc9535
@@ -57,7 +58,7 @@ def get_evaluation_result(
     :param context: the evaluation context
     :return: EvaluationResult containing the context, flags, and segments
     """
-    enrich_context(context)
+    context = enrich_context(context)
     segments, segment_overrides = evaluate_segments(context)
     flags = evaluate_features(context, segment_overrides)
 
@@ -68,19 +69,21 @@ def get_evaluation_result(
 
 
 def enrich_context(
-    context: _EvaluationContextAnyMeta,
-) -> None:
+    context: EvaluationContext[SegmentMetadataT, FeatureMetadataT],
+) -> EvaluationContext[SegmentMetadataT, FeatureMetadataT]:
     """
     Enrich the evaluation context in-place by ensuring that:
      - `$.identity.key` is set
 
     :param context: the evaluation context to enrich
     """
+    context = deepcopy(context)
     if identity_context := context.get("identity"):
         if not identity_context.get("key"):
             identity_context["key"] = (
                 f"{context['environment']['key']}_{identity_context['identifier']}"
             )
+    return context
 
 
 def evaluate_segments(

tests/unit/test_engine.py

@@ -377,13 +377,13 @@ class CustomSegmentMetadata(TypedDict):
     result = get_evaluation_result(evaluation_context)
 
     # Then
-    assert result["segments"][0]["metadata"] is segment_metadata
+    assert result["segments"][0]["metadata"] == segment_metadata
     reveal_type(result["segments"][0]["metadata"])  # CustomSegmentMetadata
 
 
 def test_segment_metadata_generic_type__default__returns_expected() -> None:
     # Given
-    segment_metadata = {"hello": object()}
+    segment_metadata = {"hello": [{"nested": True}]}
 
     # we don't specify generic type, but mypy is happy with this
     evaluation_context: EvaluationContext = {
@@ -414,7 +414,7 @@ def test_segment_metadata_generic_type__default__returns_expected() -> None:
     result = get_evaluation_result(evaluation_context)
 
     # Then
-    assert result["segments"][0]["metadata"] is segment_metadata
+    assert result["segments"][0]["metadata"] == segment_metadata
     reveal_type(result["segments"][0]["metadata"])  # Mapping[str, object]
 
 
@@ -471,13 +471,13 @@ class CustomFeatureMetadata(TypedDict):
     result = get_evaluation_result(evaluation_context)
 
     # Then
-    assert result["flags"]["feature_1"]["metadata"] is feature_metadata
+    assert result["flags"]["feature_1"]["metadata"] == feature_metadata
     reveal_type(result["flags"]["feature_1"]["metadata"])  # CustomFeatureMetadata
 
 
 def test_feature_metadata_generic_type__default__returns_expected() -> None:
     # Given
-    feature_metadata = {"hello": object()}
+    feature_metadata = {"hello": [{"nested": True}]}
 
     # we don't specify generic type, but mypy is happy with this
     evaluation_context: EvaluationContext = {
@@ -525,5 +525,5 @@ def test_feature_metadata_generic_type__default__returns_expected() -> None:
     result = get_evaluation_result(evaluation_context)
 
     # Then
-    assert result["flags"]["feature_1"]["metadata"] is feature_metadata
+    assert result["flags"]["feature_1"]["metadata"] == feature_metadata
     reveal_type(result["flags"]["feature_1"]["metadata"])  # Mapping[str, object]