From 4970f5d6590cda345ee286ced85871532aa27846 Mon Sep 17 00:00:00 2001 From: AlexWaygood Date: Wed, 10 May 2023 19:36:05 +0100 Subject: [PATCH 1/3] Optimise `dataclasses.asdict` for the common case Co-authored-by: David Ellis --- Lib/dataclasses.py | 17 ++++++++++++----- ...23-05-10-19-33-36.gh-issue-103000.j0KSfD.rst | 2 ++ 2 files changed, 14 insertions(+), 5 deletions(-) create mode 100644 Misc/NEWS.d/next/Library/2023-05-10-19-33-36.gh-issue-103000.j0KSfD.rst diff --git a/Lib/dataclasses.py b/Lib/dataclasses.py index b0b8a773b7594f..3eacba840db426 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 00000000000000..e88481495c2208 --- /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`. From 29231d5a6537a499e605f497754d55b074c2a0d3 Mon Sep 17 00:00:00 2001 From: Alex Waygood Date: Wed, 10 May 2023 19:45:15 +0100 Subject: [PATCH 2/3] Update 2023-05-10-19-33-36.gh-issue-103000.j0KSfD.rst --- .../next/Library/2023-05-10-19-33-36.gh-issue-103000.j0KSfD.rst | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) 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 index e88481495c2208..aeaba2b55e5661 100644 --- 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 @@ -1,2 +1,2 @@ Improve performance of :func:`dataclasses.asdict` for the common case where -`dict_factory` is `dict`. +`dict_factory` is `dict`. Patch by David C Ellis. From 4e01d46cfaf9c797a940efc48c29db11a1bf7fcd Mon Sep 17 00:00:00 2001 From: Alex Waygood Date: Wed, 10 May 2023 19:48:02 +0100 Subject: [PATCH 3/3] this isn't markdown --- .../next/Library/2023-05-10-19-33-36.gh-issue-103000.j0KSfD.rst | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) 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 index aeaba2b55e5661..f84ec5c8b3caf6 100644 --- 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 @@ -1,2 +1,2 @@ Improve performance of :func:`dataclasses.asdict` for the common case where -`dict_factory` is `dict`. Patch by David C Ellis. +*dict_factory* is ``dict``. Patch by David C Ellis. pFad - Phonifier reborn

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