Fix issue on checking variable assignment for code verification (#337)

The previous check accidently forbids complex assignment, which should
be allowd.

See this issue:
#277

taskweaver/code_interpreter/code_verification.py

@@ -42,6 +42,9 @@ def _is_allowed_function_call(self, func_name: str) -> bool:
         return True
 
     def visit_Call(self, node):
+        if self.allowed_functions is None and self.blocked_functions is None:
+            return
+
         if isinstance(node.func, ast.Name):
             function_name = node.func.id
         elif isinstance(node.func, ast.Attribute):
@@ -67,6 +70,9 @@ def _is_allowed_module_import(self, mod_name: str) -> bool:
         return True
 
     def visit_Import(self, node):
+        if self.allowed_modules is None and self.blocked_modules is None:
+            return
+
         for alias in node.names:
             if "." in alias.name:
                 module_name = alias.name.split(".")[0]
@@ -80,6 +86,9 @@ def visit_Import(self, node):
                 )
 
     def visit_ImportFrom(self, node):
+        if self.allowed_modules is None and self.blocked_modules is None:
+            return
+
         if "." in node.module:
             module_name = node.module.split(".")[0]
         else:
@@ -99,21 +108,23 @@ def _is_allowed_variable(self, var_name: str) -> bool:
         return True
 
     def visit_Assign(self, node: ast.Assign):
+        if self.allowed_variables is None:
+            return
+
         for target in node.targets:
+            variable_names = []
             if isinstance(target, ast.Name):
-                variable_name = target.id
+                variable_names.append(target.id)
             else:
-                self.errors.append(
-                    f"Error on line {node.lineno}: {self.lines[node.lineno - 1]} "
-                    "=> Complex assignments are not allowed.",
-                )
-                continue
-
-            if not self._is_allowed_variable(variable_name):
-                self.errors.append(
-                    f"Error on line {node.lineno}: {self.lines[node.lineno - 1]} "
-                    f"=> Assigning to {variable_name} is not allowed.",
-                )
+                for name in ast.walk(target):
+                    if isinstance(name, ast.Name):
+                        variable_names.append(name.id)
+            for variable_name in variable_names:
+                if not self._is_allowed_variable(variable_name):
+                    self.errors.append(
+                        f"Error on line {node.lineno}: {self.lines[node.lineno - 1]} "
+                        f"=> Assigning to {variable_name} is not allowed.",
+                    )
 
     def generic_visit(self, node):
         super().generic_visit(node)

tests/unit_tests/test_code_verification.py

@@ -212,6 +212,16 @@ def test_allow_variable():
     print("---->", code_verify_errors)
     assert len(code_verify_errors) == 0
 
+    code_snippet = "name, age = 'John', 25\n" "print(f'Hello, {name}! You are {age} years old.')\n"
+    allowed_variables = ["name", "age"]
+    code_verify_errors = code_snippet_verification(
+        code_snippet,
+        code_verification_on=True,
+        allowed_variables=allowed_variables,
+    )
+    print("---->", code_verify_errors)
+    assert len(code_verify_errors) == 0
+
 
 def test_magic_code():
     code_snippet = (