Fixed #33651 -- Added support for prefetching GenericForeignKey.

Co-authored-by: revanthgss <revanthgss@almabase.com>
Co-authored-by: Mariusz Felisiak <felisiak.mariusz@gmail.com>

django/db/models/query.py

@@ -33,6 +33,7 @@ from django.db.models.utils import (
     resolve_callables,
 )
 from django.utils import timezone
+from django.utils.deprecation import RemovedInDjango60Warning
 from django.utils.functional import cached_property, partition
 
 # The maximum number of results to fetch in a get() query.
@@ -2236,8 +2237,21 @@ class Prefetch:
         return to_attr, as_attr
 
     def get_current_queryset(self, level):
-        if self.get_current_prefetch_to(level) == self.prefetch_to:
-            return self.queryset
+        warnings.warn(
+            "Prefetch.get_current_queryset() is deprecated. Use "
+            "get_current_querysets() instead.",
+            RemovedInDjango60Warning,
+            stacklevel=2,
+        )
+        querysets = self.get_current_querysets(level)
+        return querysets[0] if querysets is not None else None
+
+    def get_current_querysets(self, level):
+        if (
+            self.get_current_prefetch_to(level) == self.prefetch_to
+            and self.queryset is not None
+        ):
+            return [self.queryset]
         return None
 
     def __eq__(self, other):
@@ -2425,9 +2439,9 @@ async def aprefetch_related_objects(model_instances, *related_lookups):
 def get_prefetcher(instance, through_attr, to_attr):
     """
     For the attribute 'through_attr' on the given instance, find
-    an object that has a get_prefetch_queryset().
+    an object that has a get_prefetch_querysets().
     Return a 4 tuple containing:
-    (the object with get_prefetch_queryset (or None),
+    (the object with get_prefetch_querysets (or None),
      the descriptor object representing this relationship (or None),
      a boolean that is False if the attribute was not found at all,
      a function that takes an instance and returns a boolean that is True if
@@ -2462,8 +2476,12 @@ def get_prefetcher(instance, through_attr, to_attr):
         attr_found = True
         if rel_obj_descriptor:
             # singly related object, descriptor object has the
-            # get_prefetch_queryset() method.
-            if hasattr(rel_obj_descriptor, "get_prefetch_queryset"):
+            # get_prefetch_querysets() method.
+            if (
+                hasattr(rel_obj_descriptor, "get_prefetch_querysets")
+                # RemovedInDjango60Warning.
+                or hasattr(rel_obj_descriptor, "get_prefetch_queryset")
+            ):
                 prefetcher = rel_obj_descriptor
                 # If to_attr is set, check if the value has already been set,
                 # which is done with has_to_attr_attribute(). Do not use the
@@ -2476,7 +2494,11 @@ def get_prefetcher(instance, through_attr, to_attr):
                 # the attribute on the instance rather than the class to
                 # support many related managers
                 rel_obj = getattr(instance, through_attr)
-                if hasattr(rel_obj, "get_prefetch_queryset"):
+                if (
+                    hasattr(rel_obj, "get_prefetch_querysets")
+                    # RemovedInDjango60Warning.
+                    or hasattr(rel_obj, "get_prefetch_queryset")
+                ):
                     prefetcher = rel_obj
                 if through_attr == to_attr:
 
@@ -2497,7 +2519,7 @@ def prefetch_one_level(instances, prefetcher, lookup, level):
     Return the prefetched objects along with any additional prefetches that
     must be done due to prefetch_related lookups found from default managers.
     """
-    # prefetcher must have a method get_prefetch_queryset() which takes a list
+    # prefetcher must have a method get_prefetch_querysets() which takes a list
     # of instances, and returns a tuple:
 
     # (queryset of instances of self.model that are related to passed in instances,
@@ -2510,14 +2532,34 @@ def prefetch_one_level(instances, prefetcher, lookup, level):
     # The 'values to be matched' must be hashable as they will be used
     # in a dictionary.
 
-    (
-        rel_qs,
-        rel_obj_attr,
-        instance_attr,
-        single,
-        cache_name,
-        is_descriptor,
-    ) = prefetcher.get_prefetch_queryset(instances, lookup.get_current_queryset(level))
+    if hasattr(prefetcher, "get_prefetch_querysets"):
+        (
+            rel_qs,
+            rel_obj_attr,
+            instance_attr,
+            single,
+            cache_name,
+            is_descriptor,
+        ) = prefetcher.get_prefetch_querysets(
+            instances, lookup.get_current_querysets(level)
+        )
+    else:
+        warnings.warn(
+            "The usage of get_prefetch_queryset() in prefetch_related_objects() is "
+            "deprecated. Implement get_prefetch_querysets() instead.",
+            RemovedInDjango60Warning,
+            stacklevel=2,
+        )
+        (
+            rel_qs,
+            rel_obj_attr,
+            instance_attr,
+            single,
+            cache_name,
+            is_descriptor,
+        ) = prefetcher.get_prefetch_queryset(
+            instances, lookup.get_current_querysets(level)
+        )
     # We have to handle the possibility that the QuerySet we just got back
     # contains some prefetch_related lookups. We don't want to trigger the
     # prefetch_related functionality by evaluating the query. Rather, we need