diff options
| -rw-r--r-- | Lib/dataclasses.py | 37 | ||||
| -rwxr-xr-x | Lib/test/test_dataclasses.py | 86 | ||||
| -rw-r--r-- | Misc/NEWS.d/next/Library/2018-10-17-02-15-23.bpo-33947.SRuq3T.rst | 1 |
3 files changed, 118 insertions, 6 deletions
diff --git a/Lib/dataclasses.py b/Lib/dataclasses.py index 28e9f75..71d9896 100644 --- a/Lib/dataclasses.py +++ b/Lib/dataclasses.py @@ -5,6 +5,9 @@ import types import inspect import keyword import builtins +import functools +import _thread + __all__ = ['dataclass', 'field', @@ -337,6 +340,27 @@ def _tuple_str(obj_name, fields): return f'({",".join([f"{obj_name}.{f.name}" for f in fields])},)' +# This function's logic is copied from "recursive_repr" function in +# reprlib module to avoid dependency. +def _recursive_repr(user_function): + # Decorator to make a repr function return "..." for a recursive + # call. + repr_running = set() + + @functools.wraps(user_function) + def wrapper(self): + key = id(self), _thread.get_ident() + if key in repr_running: + return '...' + repr_running.add(key) + try: + result = user_function(self) + finally: + repr_running.discard(key) + return result + return wrapper + + def _create_fn(name, args, body, *, globals=None, locals=None, return_type=MISSING): # Note that we mutate locals when exec() is called. Caller @@ -497,12 +521,13 @@ def _init_fn(fields, frozen, has_post_init, self_name): def _repr_fn(fields): - return _create_fn('__repr__', - ('self',), - ['return self.__class__.__qualname__ + f"(' + - ', '.join([f"{f.name}={{self.{f.name}!r}}" - for f in fields]) + - ')"']) + fn = _create_fn('__repr__', + ('self',), + ['return self.__class__.__qualname__ + f"(' + + ', '.join([f"{f.name}={{self.{f.name}!r}}" + for f in fields]) + + ')"']) + return _recursive_repr(fn) def _frozen_get_del_attr(cls, fields): diff --git a/Lib/test/test_dataclasses.py b/Lib/test/test_dataclasses.py index 6efe785..ff6060c 100755 --- a/Lib/test/test_dataclasses.py +++ b/Lib/test/test_dataclasses.py @@ -3169,6 +3169,92 @@ class TestReplace(unittest.TestCase): replace(c, x=3) c = replace(c, x=3, y=5) self.assertEqual(c.x, 15) + + def test_recursive_repr(self): + @dataclass + class C: + f: "C" + + c = C(None) + c.f = c + self.assertEqual(repr(c), "TestReplace.test_recursive_repr.<locals>.C(f=...)") + + def test_recursive_repr_two_attrs(self): + @dataclass + class C: + f: "C" + g: "C" + + c = C(None, None) + c.f = c + c.g = c + self.assertEqual(repr(c), "TestReplace.test_recursive_repr_two_attrs" + ".<locals>.C(f=..., g=...)") + + def test_recursive_repr_indirection(self): + @dataclass + class C: + f: "D" + + @dataclass + class D: + f: "C" + + c = C(None) + d = D(None) + c.f = d + d.f = c + self.assertEqual(repr(c), "TestReplace.test_recursive_repr_indirection" + ".<locals>.C(f=TestReplace.test_recursive_repr_indirection" + ".<locals>.D(f=...))") + + def test_recursive_repr_indirection_two(self): + @dataclass + class C: + f: "D" + + @dataclass + class D: + f: "E" + + @dataclass + class E: + f: "C" + + c = C(None) + d = D(None) + e = E(None) + c.f = d + d.f = e + e.f = c + self.assertEqual(repr(c), "TestReplace.test_recursive_repr_indirection_two" + ".<locals>.C(f=TestReplace.test_recursive_repr_indirection_two" + ".<locals>.D(f=TestReplace.test_recursive_repr_indirection_two" + ".<locals>.E(f=...)))") + + def test_recursive_repr_two_attrs(self): + @dataclass + class C: + f: "C" + g: "C" + + c = C(None, None) + c.f = c + c.g = c + self.assertEqual(repr(c), "TestReplace.test_recursive_repr_two_attrs" + ".<locals>.C(f=..., g=...)") + + def test_recursive_repr_misc_attrs(self): + @dataclass + class C: + f: "C" + g: int + + c = C(None, 1) + c.f = c + self.assertEqual(repr(c), "TestReplace.test_recursive_repr_misc_attrs" + ".<locals>.C(f=..., g=1)") + ## def test_initvar(self): ## @dataclass ## class C: diff --git a/Misc/NEWS.d/next/Library/2018-10-17-02-15-23.bpo-33947.SRuq3T.rst b/Misc/NEWS.d/next/Library/2018-10-17-02-15-23.bpo-33947.SRuq3T.rst new file mode 100644 index 0000000..bf08bac --- /dev/null +++ b/Misc/NEWS.d/next/Library/2018-10-17-02-15-23.bpo-33947.SRuq3T.rst @@ -0,0 +1 @@ +dataclasses now handle recursive reprs without raising RecursionError. |