[5.0.x] Fixed #35050 -- Fixed prefixing field names in FilteredRelation().

Thanks Mark Zorn for the report.

Regression in 59f475470494ce5b8cbff816b1e5dafcbd10a3a3.

Backport of 14917c9ae272f47d23401100faa6cefa8e1728bf from main

4 files changed, 45 insertions, 2 deletions

diff --git a/django/db/models/sql/query.py b/django/db/models/sql/query.py
index f04b1c4cc3..3320f91fa1 100644
--- a/django/db/models/sql/query.py
+++ b/django/db/models/sql/query.py
@@ -94,14 +94,16 @@ def get_child_with_renamed_prefix(prefix, replacement, child):
         return rename_prefix_from_q(prefix, replacement, child)
     if isinstance(child, tuple):
         lhs, rhs = child
-        lhs = lhs.replace(prefix, replacement, 1)
+        if lhs.startswith(prefix + LOOKUP_SEP):
+            lhs = lhs.replace(prefix, replacement, 1)
         if not isinstance(rhs, F) and hasattr(rhs, "resolve_expression"):
             rhs = get_child_with_renamed_prefix(prefix, replacement, rhs)
         return lhs, rhs
 
     if isinstance(child, F):
         child = child.copy()
-        child.name = child.name.replace(prefix, replacement, 1)
+        if child.name.startswith(prefix + LOOKUP_SEP):
+            child.name = child.name.replace(prefix, replacement, 1)
     elif hasattr(child, "resolve_expression"):
         child = child.copy()
         child.set_source_expressions(
diff --git a/docs/releases/5.0.1.txt b/docs/releases/5.0.1.txt
index 592454e893..15b735b42e 100644
--- a/docs/releases/5.0.1.txt
+++ b/docs/releases/5.0.1.txt
@@ -29,3 +29,6 @@ Bugfixes
   overflow the page and become non-interactive (:ticket:`35012`).
 
 * Added compatibility for ``oracledb`` 2.0.0 (:ticket:`35054`).
+
+* Fixed a regression in Django 5.0 where querysets referenced incorrect field
+  names from ``FilteredRelation()`` (:ticket:`35050`).
diff --git a/tests/filtered_relation/models.py b/tests/filtered_relation/models.py
index d34a86305f..765d4956e2 100644
--- a/tests/filtered_relation/models.py
+++ b/tests/filtered_relation/models.py
@@ -36,6 +36,8 @@ class Book(models.Model):
         related_query_name="book",
     )
     editor = models.ForeignKey(Editor, models.CASCADE)
+    number_editor = models.IntegerField(default=-1)
+    editor_number = models.IntegerField(default=-2)
     generic_author = GenericRelation(Author)
     state = models.CharField(max_length=9, choices=STATES, default=AVAILABLE)
 
diff --git a/tests/filtered_relation/tests.py b/tests/filtered_relation/tests.py
index 5a21a47f36..19714e8443 100644
--- a/tests/filtered_relation/tests.py
+++ b/tests/filtered_relation/tests.py
@@ -792,6 +792,42 @@ class FilteredRelationTests(TestCase):
         ).filter(my_books__isnull=True)
         self.assertSequenceEqual(qs, [])
 
+    def test_conditional_expression_rhs_contains_relation_name(self):
+        qs = Book.objects.annotate(
+            rel=FilteredRelation(
+                "editor",
+                condition=Q(id=1 * F("number_editor")),
+            )
+        ).filter(rel__isnull=True)
+        self.assertSequenceEqual(qs, [])
+
+    def test_conditional_expression_rhs_startswith_relation_name(self):
+        qs = Book.objects.annotate(
+            rel=FilteredRelation(
+                "editor",
+                condition=Q(id=1 * F("editor_number")),
+            )
+        ).filter(rel__isnull=True)
+        self.assertSequenceEqual(qs, [])
+
+    def test_conditional_expression_lhs_startswith_relation_name(self):
+        qs = Book.objects.annotate(
+            rel=FilteredRelation(
+                "editor",
+                condition=Q(editor_number__gt=1),
+            )
+        ).filter(rel__isnull=True)
+        self.assertSequenceEqual(qs, [])
+
+    def test_conditional_expression_lhs_contains_relation_name(self):
+        qs = Book.objects.annotate(
+            rel=FilteredRelation(
+                "editor",
+                condition=Q(number_editor__gt=1),
+            )
+        ).filter(rel__isnull=True)
+        self.assertSequenceEqual(qs, [])
+
 
 class FilteredRelationAggregationTests(TestCase):
     @classmethod