1 files changed, 47 insertions, 6 deletions
diff --git a/Lib/dataclasses.py b/Lib/dataclasses.py
index 0f7dc9ae6b8..86d29df0639 100644
--- a/Lib/dataclasses.py
+++ b/Lib/dataclasses.py
@@ -244,6 +244,10 @@ _ATOMIC_TYPES = frozenset({
     property,
 })
 
+# Any marker is used in `make_dataclass` to mark unannotated fields as `Any`
+# without importing `typing` module.
+_ANY_MARKER = object()
+
 
 class InitVar:
     __slots__ = ('type', )
@@ -1591,7 +1595,7 @@ def make_dataclass(cls_name, fields, *, bases=(), namespace=None, init=True,
     for item in fields:
         if isinstance(item, str):
             name = item
-            tp = 'typing.Any'
+            tp = _ANY_MARKER
         elif len(item) == 2:
             name, tp, = item
         elif len(item) == 3:
@@ -1610,15 +1614,49 @@ def make_dataclass(cls_name, fields, *, bases=(), namespace=None, init=True,
         seen.add(name)
         annotations[name] = tp
 
+    # We initially block the VALUE format, because inside dataclass() we'll
+    # call get_annotations(), which will try the VALUE format first. If we don't
+    # block, that means we'd always end up eagerly importing typing here, which
+    # is what we're trying to avoid.
+    value_blocked = True
+
+    def annotate_method(format):
+        def get_any():
+            match format:
+                case annotationlib.Format.STRING:
+                    return 'typing.Any'
+                case annotationlib.Format.FORWARDREF:
+                    typing = sys.modules.get("typing")
+                    if typing is None:
+                        return annotationlib.ForwardRef("Any", module="typing")
+                    else:
+                        return typing.Any
+                case annotationlib.Format.VALUE:
+                    if value_blocked:
+                        raise NotImplementedError
+                    from typing import Any
+                    return Any
+                case _:
+                    raise NotImplementedError
+        annos = {
+            ann: get_any() if t is _ANY_MARKER else t
+            for ann, t in annotations.items()
+        }
+        if format == annotationlib.Format.STRING:
+            return annotationlib.annotations_to_string(annos)
+        else:
+            return annos
+
     # Update 'ns' with the user-supplied namespace plus our calculated values.
     def exec_body_callback(ns):
         ns.update(namespace)
         ns.update(defaults)
-        ns['__annotations__'] = annotations
 
     # We use `types.new_class()` instead of simply `type()` to allow dynamic creation
     # of generic dataclasses.
     cls = types.new_class(cls_name, bases, {}, exec_body_callback)
+    # For now, set annotations including the _ANY_MARKER.
+    cls.__annotate__ = annotate_method
 
     # For pickling to work, the __module__ variable needs to be set to the frame
     # where the dataclass is created.
@@ -1634,10 +1672,13 @@ def make_dataclass(cls_name, fields, *, bases=(), namespace=None, init=True,
         cls.__module__ = module
 
     # Apply the normal provided decorator.
-    return decorator(cls, init=init, repr=repr, eq=eq, order=order,
-                     unsafe_hash=unsafe_hash, frozen=frozen,
-                     match_args=match_args, kw_only=kw_only, slots=slots,
-                     weakref_slot=weakref_slot)
+    cls = decorator(cls, init=init, repr=repr, eq=eq, order=order,
+                    unsafe_hash=unsafe_hash, frozen=frozen,
+                    match_args=match_args, kw_only=kw_only, slots=slots,
+                    weakref_slot=weakref_slot)
+    # Now that the class is ready, allow the VALUE format.
+    value_blocked = False
+    return cls
 
 
 def replace(obj, /, **changes):