[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

2 files changed, 8 insertions, 4 deletions

diff --git a/django/db/backends/base/schema.py b/django/db/backends/base/schema.py
index cc33740195..96d555f862 100644
--- a/django/db/backends/base/schema.py
+++ b/django/db/backends/base/schema.py
@@ -1660,7 +1660,9 @@ class BaseDatabaseSchemaEditor:
         return output
 
     def _field_should_be_altered(self, old_field, new_field, ignore=None):
-        if not old_field.concrete and not new_field.concrete:
+        if (not (old_field.concrete or old_field.many_to_many)) and (
+            not (new_field.concrete or new_field.many_to_many)
+        ):
             return False
         ignore = ignore or set()
         _, old_path, old_args, old_kwargs = old_field.deconstruct()
@@ -1692,8 +1694,10 @@ class BaseDatabaseSchemaEditor:
         ):
             old_kwargs.pop("db_default")
             new_kwargs.pop("db_default")
-        return self.quote_name(old_field.column) != self.quote_name(
-            new_field.column
+        return (
+            old_field.concrete
+            and new_field.concrete
+            and (self.quote_name(old_field.column) != self.quote_name(new_field.column))
         ) or (old_path, old_args, old_kwargs) != (new_path, new_args, new_kwargs)
 
     def _field_should_be_indexed(self, model, field):
diff --git a/django/db/backends/sqlite3/schema.py b/django/db/backends/sqlite3/schema.py
index ac6ae5efbd..077a53bf55 100644
--- a/django/db/backends/sqlite3/schema.py
+++ b/django/db/backends/sqlite3/schema.py
@@ -144,7 +144,7 @@ class DatabaseSchemaEditor(BaseDatabaseSchemaEditor):
             # Choose a default and insert it into the copy map
             if (
                 not create_field.has_db_default()
-                and not (create_field.many_to_many or create_field.generated)
+                and not create_field.generated
                 and create_field.concrete
             ):
                 mapping[create_field.column] = self.prepare_default(