[Python-checkins] bpo-33947: dataclasses no longer can raise RecursionError in repr (GF9916) (#9970)
Eric V. Smith
webhook-mailer at python.org
Fri Oct 19 13:28:34 EDT 2018
https://github.com/python/cpython/commit/b9182aa7dad8991fc8768ae494b45b5f7c316aca
commit: b9182aa7dad8991fc8768ae494b45b5f7c316aca
branch: 3.7
author: Miss Islington (bot) <31488909+miss-islington at users.noreply.github.com>
committer: Eric V. Smith <ericvsmith at users.noreply.github.com>
date: 2018-10-19T13:28:30-04:00
summary:
bpo-33947: dataclasses no longer can raise RecursionError in repr (GF9916) (#9970)
The reprlib code was copied here instead of importing reprlib. I'm not sure if we really need to avoid the import, but since I expect dataclasses to be more common that reprlib, it seems wise. Plus, the code is small.
(cherry picked from commit dd13c88b5371e13fc16b84e2f9b8715d917de269)
Co-authored-by: Srinivas Thatiparthy (శ్రీనివాస్ తాటిపర్తి) <srinivasreddy at users.noreply.github.com>
files:
A Misc/NEWS.d/next/Library/2018-10-17-02-15-23.bpo-33947.SRuq3T.rst
M Lib/dataclasses.py
M Lib/test/test_dataclasses.py
diff --git a/Lib/dataclasses.py b/Lib/dataclasses.py
index 28e9f75127b1..71d9896a1052 100644
--- a/Lib/dataclasses.py
+++ b/Lib/dataclasses.py
@@ -5,6 +5,9 @@
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 6efe785bc328..ff6060c6d283 100755
--- a/Lib/test/test_dataclasses.py
+++ b/Lib/test/test_dataclasses.py
@@ -3169,6 +3169,92 @@ def __post_init__(self, y):
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 000000000000..bf08bac13cc7
--- /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.
More information about the Python-checkins
mailing list