simplify Lib/inspect.py

Author: skirpichev

Lib/inspect.py

@@ -2215,9 +2215,11 @@ def wrap_value(s):
             except NameError:
                 raise ValueError
 
-        if isinstance(value, (str, int, float, bytes, bool, type(None),
-                              sentinel)):
-            return ast.parse(s, mode='eval').body
+        if isinstance(value, (str, int, float, bytes, bool, type(None))):
+            return ast.Constant(value)
+        elif isinstance(value, sentinel):
+            return ast.Call(func=ast.Name(id='sentinel'),
+                            args=[ast.Constant(value.__name__)])
         raise ValueError
 
     class RewriteSymbolics(ast.NodeTransformer):
@@ -2238,23 +2240,28 @@ 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_source = ast.unparse(default_node)
-                try:
-                    default = ast.literal_eval(default_source)
-                except ValueError:
-                    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:
+                default = ast.literal_eval(default_node)
+            except ValueError:
                 raise ValueError("{!r} builtin has invalid signature".format(obj)) from None
         parameters.append(Parameter(name, kind, default=default, annotation=empty))