Fix lint and MRO issues in Pydantic compatibility tests

- Remove unused pytest import to fix lint error
- Change inheritance order to FlowTrackable, BaseModel to fix MRO error
- Follows same pattern as LiteAgent and Crew classes in codebase

Co-Authored-By: João <joao@crewai.com>

src/crewai/flow/flow_trackable.py

@@ -20,7 +20,8 @@ class FlowTrackable(BaseModel):
     )
 
     @model_validator(mode="after")
-    def _set_parent_flow(self, max_depth: int = 5) -> "FlowTrackable":
+    def _set_parent_flow(self) -> "FlowTrackable":
+        max_depth = 5
         frame = inspect.currentframe()
 
         try:

tests/test_pydantic_compatibility.py

@@ -0,0 +1,133 @@
+"""Tests for Pydantic version compatibility issues."""
+
+from unittest.mock import patch, MagicMock
+from pydantic import BaseModel
+
+from crewai.flow.flow_trackable import FlowTrackable
+from crewai.flow import Flow
+
+
+class TestFlowTrackable(FlowTrackable, BaseModel):
+    """Test class that inherits from FlowTrackable for testing."""
+    name: str = "test"
+
+
+class MockFlow(Flow):
+    """Mock Flow class for testing."""
+    
+    def __init__(self):
+        super().__init__()
+
+
+def test_flow_trackable_instantiation():
+    """Test that FlowTrackable can be instantiated without ValidationInfo errors."""
+    trackable = TestFlowTrackable()
+    assert trackable.name == "test"
+    assert trackable.parent_flow is None
+
+
+def test_flow_trackable_with_parent_flow():
+    """Test that FlowTrackable correctly identifies parent flow from call stack."""
+    mock_flow = MockFlow()
+    
+    def create_trackable_in_flow():
+        return TestFlowTrackable()
+    
+    with patch('inspect.currentframe') as mock_frame:
+        mock_current_frame = MagicMock()
+        mock_parent_frame = MagicMock()
+        mock_flow_frame = MagicMock()
+        
+        mock_current_frame.f_back = mock_parent_frame
+        mock_parent_frame.f_back = mock_flow_frame
+        mock_flow_frame.f_back = None
+        
+        mock_parent_frame.f_locals = {}
+        mock_flow_frame.f_locals = {"self": mock_flow}
+        
+        mock_frame.return_value = mock_current_frame
+        
+        trackable = create_trackable_in_flow()
+        assert trackable.parent_flow == mock_flow
+
+
+def test_flow_trackable_no_parent_flow():
+    """Test that FlowTrackable handles case where no parent flow is found."""
+    with patch('inspect.currentframe') as mock_frame:
+        mock_current_frame = MagicMock()
+        mock_parent_frame = MagicMock()
+        
+        mock_current_frame.f_back = mock_parent_frame
+        mock_parent_frame.f_back = None
+        mock_parent_frame.f_locals = {"self": "not_a_flow"}
+        
+        mock_frame.return_value = mock_current_frame
+        
+        trackable = TestFlowTrackable()
+        assert trackable.parent_flow is None
+
+
+def test_flow_trackable_max_depth_limit():
+    """Test that FlowTrackable respects max_depth limit when searching for parent flow."""
+    with patch('inspect.currentframe') as mock_frame:
+        mock_frames = []
+        for i in range(10):
+            frame = MagicMock()
+            frame.f_locals = {"self": f"frame_{i}"}
+            mock_frames.append(frame)
+        
+        for i in range(len(mock_frames) - 1):
+            mock_frames[i].f_back = mock_frames[i + 1]
+        mock_frames[-1].f_back = None
+        
+        mock_frame.return_value = mock_frames[0]
+        
+        trackable = TestFlowTrackable()
+        assert trackable.parent_flow is None
+
+
+def test_flow_trackable_none_frame():
+    """Test that FlowTrackable handles None frame gracefully."""
+    with patch('inspect.currentframe', return_value=None):
+        trackable = TestFlowTrackable()
+        assert trackable.parent_flow is None
+
+
+def test_pydantic_model_validator_signature():
+    """Test that the model validator has the correct signature for Pydantic compatibility."""
+    import inspect
+    from crewai.flow.flow_trackable import FlowTrackable
+    
+    validator_method = FlowTrackable._set_parent_flow
+    sig = inspect.signature(validator_method)
+    
+    params = list(sig.parameters.keys())
+    assert params == ['self'], f"Expected ['self'], got {params}"
+    
+    assert sig.return_annotation == "FlowTrackable"
+
+
+def test_crew_instantiation_with_flow_trackable():
+    """Test that Crew can be instantiated without ValidationInfo errors (reproduces issue #3011)."""
+    from crewai import Crew, Agent, Task
+    
+    agent = Agent(
+        role="Test Agent",
+        goal="Test goal",
+        backstory="Test backstory"
+    )
+    
+    task = Task(
+        description="Test task",
+        expected_output="Test output",
+        agent=agent
+    )
+    
+    crew = Crew(
+        agents=[agent],
+        tasks=[task]
+    )
+    
+    assert crew is not None
+    assert len(crew.agents) == 1
+    assert len(crew.tasks) == 1