don't misuse ast.Constant() in the inspect module

Author: skirpichev

Lib/inspect.py

@@ -2209,7 +2209,7 @@ def wrap_value(s):
 
         if isinstance(value, (str, int, float, bytes, bool, type(None),
                               sentinel)):
-            return ast.Constant(value)
+            return ast.parse(s)
         raise ValueError
 
     class RewriteSymbolics(ast.NodeTransformer):
@@ -2230,28 +2230,20 @@ def visit_Name(self, node):
                 raise ValueError()
             return wrap_value(node.id)
 
-        def visit_BinOp(self, node):
-            # Support constant folding of a couple simple binary operations
-            # commonly used to define default values in text signatures
-            left = self.visit(node.left)
-            right = self.visit(node.right)
-            if not isinstance(left, ast.Constant) or not isinstance(right, ast.Constant):
-                raise ValueError
-            if isinstance(node.op, ast.Add):
-                return ast.Constant(left.value + right.value)
-            elif isinstance(node.op, ast.Sub):
-                return ast.Constant(left.value - right.value)
-            elif isinstance(node.op, ast.BitOr):
-                return ast.Constant(left.value | right.value)
-            raise ValueError
-
     def p(name_node, default_node, default=empty):
         name = parse_name(name_node)
         if default_node and default_node is not _empty:
             try:
                 default_node = RewriteSymbolics().visit(default_node)
-                default = ast.literal_eval(default_node)
-            except ValueError:
+                default_source = ast.unparse(default_node)
+                try:
+                    default = eval(default_source, module_dict)
+                except NameError:
+                    try:
+                        default = eval(default_source, sys_module_dict)
+                    except NameError:
+                        raise ValueError
+            except ValueError as exc:
                 raise ValueError("{!r} builtin has invalid signature".format(obj)) from None
         parameters.append(Parameter(name, kind, default=default, annotation=empty))
 

Lib/test/test_inspect/test_inspect.py

@@ -6287,9 +6287,9 @@ def test_operator_module_has_signatures(self):
         self._test_module_has_signatures(operator)
 
     def test_os_module_has_signatures(self):
-        unsupported_signature = {'chmod', 'utime'}
+        unsupported_signature = {'utime'}
         unsupported_signature |= {name for name in
-            ['get_terminal_size', 'link', 'register_at_fork', 'startfile']
+            ['get_terminal_size', 'register_at_fork', 'startfile']
             if hasattr(os, name)}
         self._test_module_has_signatures(os, unsupported_signature=unsupported_signature)
 
@@ -6339,9 +6339,7 @@ def test_threading_module_has_signatures(self):
     def test_thread_module_has_signatures(self):
         import _thread
         no_signature = {'RLock'}
-        unsupported_signature = {'interrupt_main'}
-        self._test_module_has_signatures(_thread, no_signature,
-                                         unsupported_signature)
+        self._test_module_has_signatures(_thread, no_signature)
 
     def test_time_module_has_signatures(self):
         no_signature = {