diff options
| -rw-r--r-- | Lib/dataclasses.py | 17 | ||||
| -rw-r--r-- | Misc/NEWS.d/next/Library/2023-05-10-19-33-36.gh-issue-103000.j0KSfD.rst | 2 |
2 files changed, 14 insertions, 5 deletions
diff --git a/Lib/dataclasses.py b/Lib/dataclasses.py index b0b8a77..3eacba8 100644 --- a/Lib/dataclasses.py +++ b/Lib/dataclasses.py @@ -1324,11 +1324,18 @@ def _asdict_inner(obj, dict_factory): if type(obj) in _ATOMIC_TYPES: return obj elif _is_dataclass_instance(obj): - result = [] - for f in fields(obj): - value = _asdict_inner(getattr(obj, f.name), dict_factory) - result.append((f.name, value)) - return dict_factory(result) + # fast path for the common case + if dict_factory is dict: + return { + f.name: _asdict_inner(getattr(obj, f.name), dict) + for f in fields(obj) + } + else: + result = [] + for f in fields(obj): + value = _asdict_inner(getattr(obj, f.name), dict_factory) + result.append((f.name, value)) + return dict_factory(result) elif isinstance(obj, tuple) and hasattr(obj, '_fields'): # obj is a namedtuple. Recurse into it, but the returned # object is another namedtuple of the same type. This is diff --git a/Misc/NEWS.d/next/Library/2023-05-10-19-33-36.gh-issue-103000.j0KSfD.rst b/Misc/NEWS.d/next/Library/2023-05-10-19-33-36.gh-issue-103000.j0KSfD.rst new file mode 100644 index 0000000..f84ec5c --- /dev/null +++ b/Misc/NEWS.d/next/Library/2023-05-10-19-33-36.gh-issue-103000.j0KSfD.rst @@ -0,0 +1,2 @@ +Improve performance of :func:`dataclasses.asdict` for the common case where +*dict_factory* is ``dict``. Patch by David C Ellis. |