diff options
| -rw-r--r-- | Lib/dataclasses.py | 16 | ||||
| -rw-r--r-- | Misc/NEWS.d/next/Library/2018-01-07-11-32-42.bpo-32506.MaT-zU.rst | 2 |
2 files changed, 10 insertions, 8 deletions
diff --git a/Lib/dataclasses.py b/Lib/dataclasses.py index 9e186c3..d800549 100644 --- a/Lib/dataclasses.py +++ b/Lib/dataclasses.py @@ -1,7 +1,6 @@ import sys import types from copy import deepcopy -import collections import inspect __all__ = ['dataclass', @@ -448,11 +447,11 @@ def _set_attribute(cls, name, value): def _process_class(cls, repr, eq, order, hash, init, frozen): - # Use an OrderedDict because: - # - Order matters! - # - Derived class fields overwrite base class fields, but the - # order is defined by the base class, which is found first. - fields = collections.OrderedDict() + # Now that dicts retain insertion order, there's no reason to use + # an ordered dict. I am leveraging that ordering here, because + # derived class fields overwrite base class fields, but the order + # is defined by the base class, which is found first. + fields = {} # Find our base classes in reverse MRO order, and exclude # ourselves. In reversed order so that more derived classes @@ -612,7 +611,8 @@ def fields(class_or_instance): except AttributeError: raise TypeError('must be called with a dataclass type or instance') - # Exclude pseudo-fields. + # Exclude pseudo-fields. Note that fields is sorted by insertion + # order, so the order of the tuple is as the fields were defined. return tuple(f for f in fields.values() if f._field_type is _FIELD) @@ -735,7 +735,7 @@ def make_dataclass(cls_name, fields, *, bases=(), namespace=None, init=True, # Copy namespace since we're going to mutate it. namespace = namespace.copy() - anns = collections.OrderedDict() + anns = {} for item in fields: if isinstance(item, str): name = item diff --git a/Misc/NEWS.d/next/Library/2018-01-07-11-32-42.bpo-32506.MaT-zU.rst b/Misc/NEWS.d/next/Library/2018-01-07-11-32-42.bpo-32506.MaT-zU.rst new file mode 100644 index 0000000..e524769 --- /dev/null +++ b/Misc/NEWS.d/next/Library/2018-01-07-11-32-42.bpo-32506.MaT-zU.rst @@ -0,0 +1,2 @@ +Now that dict is defined as keeping insertion order, drop OrderedDict and +just use plain dict. |