refactor: change class name validation to raise errors instead of generating defaults

- Remove default value generation (Crew prefix/suffix, DefaultCrew fallback)
- Raise ValueError with descriptive messages for invalid class names
- Update tests to expect validation errors instead of default corrections
- Addresses GitHub comment feedback from lucasgomide about strict validation

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

src/crewai/cli/create_crew.py

@@ -21,20 +21,25 @@ def create_folder_structure(name, parent_folder=None):
     folder_name = name.replace(" ", "_").replace("-", "_").lower()
     
     if not name.strip():
-        class_name = "DefaultCrew"
-    else:
-        class_name = name.replace("_", " ").replace("-", " ").title().replace(" ", "")
-        
-        class_name = re.sub(r'[^a-zA-Z0-9_]', '', class_name)
-        
-        if class_name and class_name[0].isdigit():
-            class_name = "Crew" + class_name
-        
-        if not class_name:
-            class_name = "DefaultCrew"
-        
-        if keyword.iskeyword(class_name) or class_name in ('True', 'False', 'None'):
-            class_name = class_name + "Crew"
+        raise ValueError("Project name cannot be empty or contain only whitespace")
+    
+    class_name = name.replace("_", " ").replace("-", " ").title().replace(" ", "")
+    
+    class_name = re.sub(r'[^a-zA-Z0-9_]', '', class_name)
+    
+    if not class_name:
+        raise ValueError(f"Project name '{name}' contains no valid characters for a Python class name")
+    
+    if class_name[0].isdigit():
+        raise ValueError(f"Project name '{name}' would generate class name '{class_name}' which cannot start with a digit")
+    
+    # Check if the original name (before title casing) is a keyword
+    original_name_clean = re.sub(r'[^a-zA-Z0-9_]', '', name.replace("_", "").replace("-", "").lower())
+    if keyword.iskeyword(original_name_clean) or keyword.iskeyword(class_name) or class_name in ('True', 'False', 'None'):
+        raise ValueError(f"Project name '{name}' would generate class name '{class_name}' which is a reserved Python keyword")
+    
+    if not class_name.isidentifier():
+        raise ValueError(f"Project name '{name}' would generate invalid Python class name '{class_name}'")
 
     if parent_folder:
         folder_path = Path(parent_folder) / folder_name

tests/cli/test_create_crew.py

@@ -149,70 +149,48 @@ def test_create_folder_structure_handles_spaces_and_dashes_with_slash():
         assert folder_path.exists()
 
 
-def test_create_folder_structure_handles_invalid_class_name_edge_cases():
+def test_create_folder_structure_raises_error_for_invalid_class_names():
     with tempfile.TemporaryDirectory() as temp_dir:
         os.chdir(temp_dir)
         
-        folder_path, folder_name, class_name = create_folder_structure("123project/")
-        assert folder_name == "123project"
-        assert class_name == "Crew123Project"
-        assert class_name.isidentifier()
-        assert folder_path.exists()
+        invalid_cases = [
+            ("123project/", "cannot start with a digit"),
+            ("True/", "reserved Python keyword"),
+            ("False/", "reserved Python keyword"), 
+            ("None/", "reserved Python keyword"),
+            ("class/", "reserved Python keyword"),
+            ("def/", "reserved Python keyword"),
+            ("   /", "empty or contain only whitespace"),
+            ("", "empty or contain only whitespace"),
+            ("@#$/", "contains no valid characters"),
+        ]
         
-        folder_path, folder_name, class_name = create_folder_structure("True/")
-        assert folder_name == "true"
-        assert class_name == "TrueCrew"
-        assert class_name.isidentifier()
-        assert folder_path.exists()
-        
-        folder_path, folder_name, class_name = create_folder_structure("   /")
-        assert folder_name == "___"  # Spaces become underscores in folder_name
-        assert class_name == "DefaultCrew"  # But class_name should be DefaultCrew for whitespace-only input
-        assert class_name.isidentifier()
-        assert folder_path.exists()
-        
-        folder_path, folder_name, class_name = create_folder_structure("hello@world/")
-        assert folder_name == "hello@world"
-        assert class_name == "HelloWorld"
-        assert class_name.isidentifier()
-        assert folder_path.exists()
+        for invalid_name, expected_error in invalid_cases:
+            with pytest.raises(ValueError, match=expected_error):
+                create_folder_structure(invalid_name)
 
 
-def test_create_folder_structure_class_names_are_valid_python_identifiers():
+def test_create_folder_structure_validates_class_names():
     import keyword
     
-    test_cases = [
-        "hello/",
-        "my-project/",
-        "123project/",
-        "class/",
-        "def/",
-        "import/",
-        "True/",
-        "False/",
-        "None/",
-        "hello.world/",
-        "hello@world/",
-        "hello#world/",
-        "hello$world/",
-        "///",
-        "",
-        "   /",
-    ]
-    
     with tempfile.TemporaryDirectory() as temp_dir:
         os.chdir(temp_dir)
         
-        for i, test_case in enumerate(test_cases):
-            unique_name = f"{test_case.rstrip('/')}_test_{i}/"
-            if not test_case.strip('/'):
-                unique_name = f"empty_test_{i}/"
-                
-            folder_path, folder_name, class_name = create_folder_structure(unique_name)
-            
-            assert class_name.isidentifier(), f"Class name '{class_name}' from input '{unique_name}' is not a valid identifier"
-            assert not keyword.iskeyword(class_name), f"Class name '{class_name}' from input '{unique_name}' is a Python keyword"
-            assert class_name not in ('True', 'False', 'None'), f"Class name '{class_name}' from input '{unique_name}' is a Python built-in"
+        valid_cases = [
+            ("hello/", "hello", "Hello"),
+            ("my-project/", "my_project", "MyProject"),
+            ("hello_world/", "hello_world", "HelloWorld"),
+            ("valid123/", "valid123", "Valid123"),
+            ("hello.world/", "hello.world", "HelloWorld"),
+            ("hello@world/", "hello@world", "HelloWorld"),
+        ]
+        
+        for valid_name, expected_folder, expected_class in valid_cases:
+            folder_path, folder_name, class_name = create_folder_structure(valid_name)
+            assert folder_name == expected_folder
+            assert class_name == expected_class
+            assert class_name.isidentifier()
+            assert not keyword.iskeyword(class_name)
             
             if folder_path.exists():
                 shutil.rmtree(folder_path)