Validate explicit empty field overrides in attack executor

pyrit/executor/attack/core/attack_executor.py

@@ -183,7 +183,7 @@ async def execute_attack_from_seed_groups_async(
         if not seed_groups:
             raise ValueError("At least one seed_group must be provided")
 
-        if field_overrides and len(field_overrides) != len(seed_groups):
+        if field_overrides is not None and len(field_overrides) != len(seed_groups):
             raise ValueError(
                 f"field_overrides length ({len(field_overrides)}) must match seed_groups length ({len(seed_groups)})"
             )
@@ -197,7 +197,7 @@ async def execute_attack_from_seed_groups_async(
         async def build_params(i: int, sg: SeedAttackGroup) -> AttackParameters:
             async with semaphore:
                 combined_overrides = dict(broadcast_fields)
-                if field_overrides:
+                if field_overrides is not None:
                     combined_overrides.update(field_overrides[i])
                 return await params_type.from_seed_group_async(
                     seed_group=sg,
@@ -248,7 +248,7 @@ async def execute_attack_async(
         if not objectives:
             raise ValueError("At least one objective must be provided")
 
-        if field_overrides and len(field_overrides) != len(objectives):
+        if field_overrides is not None and len(field_overrides) != len(objectives):
             raise ValueError(
                 f"field_overrides length ({len(field_overrides)}) must match objectives length ({len(objectives)})"
             )
@@ -262,7 +262,7 @@ async def execute_attack_async(
             fields = dict(broadcast_fields)
 
             # Apply per-objective overrides
-            if field_overrides:
+            if field_overrides is not None:
                 fields.update(field_overrides[i])
 
             # Add objective

tests/unit/executor/attack/core/test_attack_executor.py

@@ -173,6 +173,19 @@ async def test_validates_field_overrides_length(self):
                 field_overrides=[{}],  # Wrong length
             )
 
+    @pytest.mark.asyncio
+    async def test_validates_explicit_empty_field_overrides(self):
+        """Test that explicit empty field_overrides still validate length."""
+        attack = create_mock_attack()
+        executor = AttackExecutor()
+
+        with pytest.raises(ValueError, match="field_overrides length .* must match"):
+            await executor.execute_attack_async(
+                attack=attack,
+                objectives=["Obj1", "Obj2"],
+                field_overrides=[],
+            )
+
     @pytest.mark.asyncio
     async def test_concurrency_control(self):
         """Test that concurrency is properly limited."""
@@ -322,6 +335,21 @@ async def capture_from_seed_group_async(*, seed_group, **kwargs):
             # Restore the original to prevent test pollution in parallel test runs
             attack.params_type.from_seed_group_async = original_from_seed_group_async
 
+    @pytest.mark.asyncio
+    async def test_validates_explicit_empty_field_overrides_for_seed_groups(self):
+        """Test that explicit empty field_overrides still validate seed group length."""
+        attack = create_mock_attack()
+        executor = AttackExecutor()
+        sg1 = create_seed_group("Objective 1")
+        sg2 = create_seed_group("Objective 2")
+
+        with pytest.raises(ValueError, match="field_overrides length .* must match"):
+            await executor.execute_attack_from_seed_groups_async(
+                attack=attack,
+                seed_groups=[sg1, sg2],
+                field_overrides=[],
+            )
+
 
 @pytest.mark.usefixtures("patch_central_database")
 class TestPartialFailureHandling: