diff --git a/Lib/dataclasses.py b/Lib/dataclasses.py
index 7a24f8a9e5ccee..881d2fa422d582 100644
--- a/Lib/dataclasses.py
+++ b/Lib/dataclasses.py
@@ -1,11 +1,7 @@
-import re
import sys
-import copy
import types
-import inspect
import keyword
import itertools
-import annotationlib
import abc
from reprlib import recursive_repr
@@ -219,7 +215,7 @@ def __repr__(self):
# String regex that string annotations for ClassVar or InitVar must match.
# Allows "identifier.identifier[" or "identifier[".
# https://bugs.python.org/issue33453 for details.
-_MODULE_IDENTIFIER_RE = re.compile(r'^(?:\s*(\w+)\s*\.)?\s*(\w+)')
+_MODULE_IDENTIFIER_RE = None
# Atomic immutable types which don't require any recursive handling and for which deepcopy
# returns the same object. We can provide a fast-path for these types in asdict and astuple.
@@ -747,6 +743,11 @@ def _is_type(annotation, cls, a_module, a_type, is_type_predicate):
# correct global and local namespaces. However that would involve
# a eval() penalty for every single field of every dataclass
# that's defined. It was judged not worth it.
+ global _MODULE_IDENTIFIER_RE
+
+ if _MODULE_IDENTIFIER_RE is None:
+ import re
+ _MODULE_IDENTIFIER_RE = re.compile(r'^(?:\s*(\w+)\s*\.)?\s*(\w+)')
match = _MODULE_IDENTIFIER_RE.match(annotation)
if match:
@@ -982,6 +983,7 @@ def _process_class(cls, init, repr, eq, order, unsafe_hash, frozen,
# actual default value. Pseudo-fields ClassVars and InitVars are
# included, despite the fact that they're not real fields. That's
# dealt with later.
+ import annotationlib
cls_annotations = annotationlib.get_annotations(
cls, format=annotationlib.Format.FORWARDREF)
@@ -1160,6 +1162,8 @@ def _process_class(cls, init, repr, eq, order, unsafe_hash, frozen,
if not getattr(cls, '__doc__'):
# Create a class doc-string.
+ import inspect
+
try:
# In some cases fetching a signature is not possible.
# But, we surely should not fail in this case.
@@ -1318,6 +1322,8 @@ def _add_slots(cls, is_frozen, weakref_slot, defined_fields):
# original class. We can break out of this loop as soon as we
# make an update, since all closures for a class will share a
# given cell.
+ import inspect
+
for member in newcls.__dict__.values():
# If this is a wrapped function, unwrap it.
member = inspect.unwrap(member)
@@ -1484,7 +1490,8 @@ def _asdict_inner(obj, dict_factory):
# generator
return obj_type(_asdict_inner(v, dict_factory) for v in obj)
else:
- return copy.deepcopy(obj)
+ from copy import deepcopy
+ return deepcopy(obj)
def astuple(obj, *, tuple_factory=tuple):
@@ -1544,7 +1551,8 @@ def _astuple_inner(obj, tuple_factory):
return obj_type((_astuple_inner(k, tuple_factory), _astuple_inner(v, tuple_factory))
for k, v in obj.items())
else:
- return copy.deepcopy(obj)
+ from copy import deepcopy
+ return deepcopy(obj)
def make_dataclass(cls_name, fields, *, bases=(), namespace=None, init=True,
diff --git a/Misc/NEWS.d/next/Library/2025-02-09-16-21-42.gh-issue-118761.ryMtuz.rst b/Misc/NEWS.d/next/Library/2025-02-09-16-21-42.gh-issue-118761.ryMtuz.rst
new file mode 100644
index 00000000000000..a4f850232e566b
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2025-02-09-16-21-42.gh-issue-118761.ryMtuz.rst
@@ -0,0 +1,2 @@
+Improve import time of :mod:`dataclasses` by lazy importing :mod:`re`,
+:mod:`copy`, :mod:`inspect` and :mod:`annotationlib`. Patch by Semyon Moroz.
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