Fix type checker errors in on_tool_use call

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

src/crewai/tools/tool_usage.py

@@ -141,7 +141,8 @@ class ToolUsage:
                     self._printer.print(content=f"\n\n{error}\n", color="red")
                 return error
 
-        return f"{self._use(tool_string=tool_string, tool=tool, calling=calling)}"
+        result = self._use(tool_string=tool_string, tool=tool, calling=calling)
+        return f"{result}"
 
     def _use(
         self,
@@ -149,9 +150,9 @@ class ToolUsage:
         tool: CrewStructuredTool,
         calling: Union[ToolCalling, InstructorToolCalling],
     ) -> str:
-        if self._check_tool_repeated_usage(calling=calling):  # type: ignore # _check_tool_repeated_usage of "ToolUsage" does not return a value (it only ever returns None)
+        if self._check_tool_repeated_usage(calling=calling):
             try:
-                result = self._i18n.errors("task_repeated_usage").format(
+                repeated_result = self._i18n.errors("task_repeated_usage").format(
                     tool_names=self.tools_names
                 )
                 self._telemetry.tool_repeated_usage(
@@ -159,8 +160,8 @@ class ToolUsage:
                     tool_name=tool.name,
                     attempts=self._run_attempts,
                 )
-                result = self._format_result(result=result)  # type: ignore #  "_format_result" of "ToolUsage" does not return a value (it only ever returns None)
-                return result  # type: ignore # Fix the return type of this function
+                repeated_result = self._format_result(result=repeated_result)
+                return repeated_result
 
             except Exception:
                 if self.task:
@@ -168,13 +169,15 @@ class ToolUsage:
 
         started_at = time.time()
         from_cache = False
-        result = None  # type: ignore
+        result: Optional[str] = None
 
         if self.tools_handler and self.tools_handler.cache:
-            result = self.tools_handler.cache.read(
+            cache_result = self.tools_handler.cache.read(
                 tool=calling.tool_name, input=calling.arguments
-            )  # type: ignore
-            from_cache = result is not None
+            )
+            if cache_result is not None:
+                result = cache_result
+                from_cache = True
 
         available_tool = next(
             (
@@ -236,31 +239,32 @@ class ToolUsage:
                         self._printer.print(
                             content=f"\n\n{error_message}\n", color="red"
                         )
-                    return error  # type: ignore # No return value expected
+                    return error
 
                 if self.task:
                     self.task.increment_tools_errors()
-                return self.use(calling=calling, tool_string=tool_string)  # type: ignore # No return value expected
+                return self.use(calling=calling, tool_string=tool_string)
 
             if self.tools_handler:
                 should_cache = True
-                if (
+                if available_tool is not None and (
                     hasattr(available_tool, "cache_function")
-                    and available_tool.cache_function  # type: ignore # Item "None" of "Any | None" has no attribute "cache_function"
+                    and available_tool.cache_function
                 ):
-                    should_cache = available_tool.cache_function(  # type: ignore # Item "None" of "Any | None" has no attribute "cache_function"
+                    should_cache = available_tool.cache_function(
                         calling.arguments, result
                     )
 
+                output_result = "" if result is None else result
                 self.tools_handler.on_tool_use(
-                    calling=calling, output=result, should_cache=should_cache
+                    calling=calling, output=output_result, should_cache=should_cache
                 )
         self._telemetry.tool_usage(
             llm=self.function_calling_llm,
             tool_name=tool.name,
             attempts=self._run_attempts,
         )
-        result = self._format_result(result=result)  # type: ignore # "_format_result" of "ToolUsage" does not return a value (it only ever returns None)
+        result = self._format_result(result=result)
         data = {
             "result": result,
             "tool_name": tool.name,
@@ -275,12 +279,13 @@ class ToolUsage:
             result=result,
         )
 
-        if (
+        if available_tool is not None and (
             hasattr(available_tool, "result_as_answer")
-            and available_tool.result_as_answer  # type: ignore # Item "None" of "Any | None" has no attribute "cache_function"
+            and available_tool.result_as_answer
         ):
-            result_as_answer = available_tool.result_as_answer  # type: ignore # Item "None" of "Any | None" has no attribute "result_as_answer"
-            data["result_as_answer"] = result_as_answer  # type: ignore
+            result_as_answer = available_tool.result_as_answer
+            if isinstance(result_as_answer, bool):
+                data["result_as_answer"] = result_as_answer
 
         if self.agent and hasattr(self.agent, "tools_results"):
             self.agent.tools_results.append(data)
@@ -448,7 +453,7 @@ class ToolUsage:
                     self.task.increment_tools_errors()
                 if self.agent and self.agent.verbose:
                     self._printer.print(content=f"\n\n{e}\n", color="red")
-                return ToolUsageErrorException(  # type: ignore # Incompatible return value type (got "ToolUsageErrorException", expected "ToolCalling | InstructorToolCalling")
+                return ToolUsageErrorException(
                     f"{self._i18n.errors('tool_usage_error').format(error=e)}\nMoving on then. {self._i18n.slice('format').format(tool_names=self.tools_names)}"
                 )
             return self._tool_calling(tool_string)

tests/test_code_interpreter_tool.py

@@ -0,0 +1,71 @@
+from typing import Any, Dict, List, Optional, Union
+from unittest.mock import MagicMock, patch
+
+import pytest
+
+from crewai import Agent, Crew, Task
+from crewai.agents.tools_handler import ToolsHandler
+from crewai.tasks.task_output import TaskOutput
+from crewai.tools import BaseTool
+from crewai.tools.structured_tool import CrewStructuredTool
+from crewai.tools.tool_calling import InstructorToolCalling, ToolCalling
+from crewai.tools.tool_usage import ToolUsage
+
+
+class TestCodeInterpreterTool(BaseTool):
+    name: str = "Test Code Interpreter"
+    description: str = "A test tool that simulates code execution."
+    result_as_answer: bool = False
+    execution_called: bool = False
+    
+    def _run(self, code: str = "", libraries_used: List[str] = []) -> str:
+        self.execution_called = True
+        return f"Code executed: {code}"
+
+
+def test_direct_tool_execution():
+    """Test that the tool can be executed directly."""
+    test_tool = TestCodeInterpreterTool()
+    result = test_tool.run("print('Hello World')")
+    assert "Code executed" in result
+    assert test_tool.execution_called
+
+
+
+
+def test_tool_usage_return_types():
+    """Test that the ToolUsage methods return the correct types."""
+    agent_mock = MagicMock()
+    task_mock = MagicMock()
+    task_mock.used_tools = 0
+    tools_handler_mock = MagicMock()
+    
+    tool_usage = ToolUsage(
+        tools_handler=tools_handler_mock,
+        tools=[],
+        task=task_mock,
+        function_calling_llm=None,
+        agent=agent_mock,
+        action=None
+    )
+    
+    i18n_mock = MagicMock()
+    i18n_mock.slice.return_value.format.return_value = "Tool description"
+    tool_usage._i18n = i18n_mock
+    
+    result = "test result"
+    formatted_result = tool_usage._format_result(result)
+    assert formatted_result is not None, "_format_result should return the result"
+    assert isinstance(formatted_result, str), "_format_result should return a string"
+    
+    result = tool_usage._should_remember_format()
+    assert isinstance(result, bool), "_should_remember_format should return a boolean"
+    
+    result = "test result"
+    remembered_result = tool_usage._remember_format(result)
+    assert remembered_result is not None, "_remember_format should return the result"
+    assert isinstance(remembered_result, str), "_remember_format should return a string"
+    
+    tool_calling_mock = MagicMock()
+    result = tool_usage._check_tool_repeated_usage(tool_calling_mock)
+    assert isinstance(result, bool), "_check_tool_repeated_usage should return a boolean"