fix: exclude-identities-when-traits-is-undefined (#96)

Author: Zaimwa9

.gitmodules

@@ -1,4 +1,4 @@
 [submodule "spec/engine-test-data"]
 	path = spec/engine-test-data
 	url = [email protected]:Flagsmith/engine-test-data.git
-	branch = main
+	branch = v3.5.0

Gemfile.lock

@@ -73,7 +73,7 @@ GEM
     ruby-progressbar (1.13.0)
     semantic (1.6.1)
     unicode-display_width (2.5.0)
-    uri (0.13.2)
+    uri (1.1.1)
 
 PLATFORMS
   ruby

lib/flagsmith/engine/segments/evaluator.rb

@@ -157,8 +157,18 @@ def traits_match_segment_condition_from_context(condition, segment_key, context)
         end
 
         def handle_percentage_split(condition, segment_key, context)
-          context_value_key = get_context_value(condition[:property], context) || get_identity_key_from_context(context)
-          hashed_percentage = hashed_percentage_for_object_ids([segment_key, context_value_key])
+          split_key = if condition[:property].nil? || condition[:property].empty?
+                        # No property specified - use identity key
+                        get_identity_key_from_context(context)
+                      else
+                        # Property specified - must exist in context
+                        get_context_value(condition[:property], context)
+                      end
+
+          # If split_key is nil, condition doesn't match
+          return false if split_key.nil?
+
+          hashed_percentage = hashed_percentage_for_object_ids([segment_key, split_key])
           hashed_percentage <= condition[:value].to_f
         end