[6.0.x] Fixed #35453 -- Made ManyToManyField.concrete False.

ManyToManyField was already excluded from fields, concrete_fields,
and local_concrete_fields in Options.

Backport of f9a44cc0fac653f8e0c2ab1cdfb12b2cc5c63fc2 from main

3 files changed, 13 insertions, 23 deletions

diff --git a/tests/composite_pk/test_update.py b/tests/composite_pk/test_update.py
index 8d786e8afb..4f3068f228 100644
--- a/tests/composite_pk/test_update.py
+++ b/tests/composite_pk/test_update.py
@@ -172,7 +172,7 @@ class CompositePKUpdateTests(TestCase):
     def test_cant_update_relation(self):
         msg = (
             "Cannot update model field <django.db.models.fields.related.ForeignObject: "
-            "user> (only non-relations and foreign keys permitted)"
+            "user> (only concrete fields are permitted)"
         )
 
         with self.assertRaisesMessage(FieldError, msg):
diff --git a/tests/model_fields/test_field_flags.py b/tests/model_fields/test_field_flags.py
index 33f3334567..778a43eb63 100644
--- a/tests/model_fields/test_field_flags.py
+++ b/tests/model_fields/test_field_flags.py
@@ -6,6 +6,7 @@ from .models import AllFieldsModel
 
 NON_CONCRETE_FIELDS = (
     models.ForeignObject,
+    models.ManyToManyField,
     GenericForeignKey,
     GenericRelation,
 )
@@ -209,7 +210,7 @@ class FieldFlagsTests(test.SimpleTestCase):
     def test_model_and_reverse_model_should_equal_on_relations(self):
         for field in AllFieldsModel._meta.get_fields():
             is_concrete_forward_field = field.concrete and field.related_model
-            if is_concrete_forward_field:
+            if is_concrete_forward_field or field.many_to_many:
                 reverse_field = field.remote_field
                 self.assertEqual(field.model, reverse_field.related_model)
                 self.assertEqual(field.related_model, reverse_field.model)
diff --git a/tests/update/tests.py b/tests/update/tests.py
index af5939a2ef..eb5d80219c 100644
--- a/tests/update/tests.py
+++ b/tests/update/tests.py
@@ -157,43 +157,32 @@ class AdvancedTests(TestCase):
         self.assertEqual(bar_qs[0].foo_id, b_foo.target)
 
     def test_update_m2m_field(self):
-        msg = (
-            "Cannot update model field "
-            "<django.db.models.fields.related.ManyToManyField: m2m_foo> "
-            "(only non-relations and foreign keys permitted)."
-        )
+        rel = "<django.db.models.fields.related.ManyToManyField: m2m_foo>"
+        msg = f"Cannot update model field {rel} (only concrete fields are permitted)."
         with self.assertRaisesMessage(FieldError, msg):
             Bar.objects.update(m2m_foo="whatever")
 
     def test_update_reverse_m2m_descriptor(self):
-        msg = (
-            "Cannot update model field <ManyToManyRel: update.bar> "
-            "(only non-relations and foreign keys permitted)."
-        )
+        rel = "<ManyToManyRel: update.bar>"
+        msg = f"Cannot update model field {rel} (only concrete fields are permitted)."
         with self.assertRaisesMessage(FieldError, msg):
             Foo.objects.update(m2m_foo="whatever")
 
     def test_update_reverse_fk_descriptor(self):
-        msg = (
-            "Cannot update model field <ManyToOneRel: update.bar> "
-            "(only non-relations and foreign keys permitted)."
-        )
+        rel = "<ManyToOneRel: update.bar>"
+        msg = f"Cannot update model field {rel} (only concrete fields are permitted)."
         with self.assertRaisesMessage(FieldError, msg):
             Foo.objects.update(bar="whatever")
 
     def test_update_reverse_o2o_descriptor(self):
-        msg = (
-            "Cannot update model field <OneToOneRel: update.bar> "
-            "(only non-relations and foreign keys permitted)."
-        )
+        rel = "<OneToOneRel: update.bar>"
+        msg = f"Cannot update model field {rel} (only concrete fields are permitted)."
         with self.assertRaisesMessage(FieldError, msg):
             Foo.objects.update(o2o_bar="whatever")
 
     def test_update_reverse_mti_parent_link_descriptor(self):
-        msg = (
-            "Cannot update model field <OneToOneRel: update.uniquenumberchild> "
-            "(only non-relations and foreign keys permitted)."
-        )
+        rel = "<OneToOneRel: update.uniquenumberchild>"
+        msg = f"Cannot update model field {rel} (only concrete fields are permitted)."
         with self.assertRaisesMessage(FieldError, msg):
             UniqueNumber.objects.update(uniquenumberchild="whatever")