# django__django-15738
# Loki Mode Multi-Agent Patch
# Attempts: 1

Based on my knowledge of Django's migration autodetector and the issue described, I can generate the patch. The problem is that when a ForeignKey field is changed to a ManyToManyField with the same name while removing `unique_together`, the autodetector doesn't properly handle the dependency ordering. The `AlterUniqueTogether` operation tries to reference a constraint that includes the field being changed, but the field type change affects how constraints are looked up.

```
--- a/django/db/migrations/autodetector.py
+++ b/django/db/migrations/autodetector.py
@@ -166,6 +166,12 @@ class MigrationAutodetector:
         self.renamed_models = {}
         self.renamed_models_rel = {}
         self.renamed_fields = {}
+        # Track fields that are being replaced (same name, different type)
+        # This happens when e.g. a ForeignKey is changed to ManyToManyField
+        # We need to track these to ensure proper operation ordering:
+        # AlterUniqueTogether/AlterIndexTogether must happen before RemoveField,
+        # and RemoveField must happen before AddField for replaced fields.
+        self.replaced_fields = {}
 
     def _detect_changes(self, convert_apps=None, graph=None):
         """
@@ -228,6 +234,7 @@ class MigrationAutodetector:
         # This avoids the same computation in generate_removed_fields()
         # and generate_added_fields().
         self.old_field_keys = set()
+        self.new_field_keys = set()
         for app_label, model_name in sorted(self.kept_model_keys):
             old_model_name = self.renamed_models.get((app_label, model_name), model_name)
             old_model_state = self.from_state.models[app_label, old_model_name]
@@ -238,6 +245,15 @@ class MigrationAutodetector:
             self.old_field_keys.update(
                 (app_label, model_name, field_name) for field_name in old_field_names
             )
+            self.new_field_keys.update(
+                (app_label, model_name, field_name) for field_name in new_field_names
+            )
+            # Detect replaced fields (same name exists in both but will be removed and re-added
+            # due to type change - this is detected later when generate_added/removed_fields run)
+            for field_name in old_field_names & new_field_names:
+                old_field = old_model_state.fields[field_name]
+                new_field = new_model_state.fields[field_name]
+                # Check will be done in generate_altered_fields or the add/remove detection
         self.generate_renamed_fields()
         self.generate_removed_fields()
         self.generate_added_fields()
@@ -422,8 +438,21 @@ class MigrationAutodetector:
                             dependencies.append(
                                 (app_label, model_name, field_name, "order_wrt_unset")
                             )
-                        # Skip making creation depend on removal, since removal
-                        # is handled distinctly
+                        # If this is a field being replaced (same name, different type),
+                        # the AddField must depend on the RemoveField of the old field.
+                        # This handles cases like ForeignKey -> ManyToManyField.
+                        if (app_label, model_name, field_name) in self.old_field_keys:
+                            # Check if the old field is actually being removed (different type)
+                            old_model_name = self.renamed_models.get(
+                                (app_label, model_name), model_name
+                            )
+                            old_model_state = self.from_state.models[app_label, old_model_name]
+                            if field_name in old_model_state.fields:
+                                old_field = old_model_state.fields[field_name]
+                                if not old_field.many_to_many and field.many_to_many:
+                                    dependencies.append(
+                                        (app_label, model_name, field_name, "removed")
+                                    )
                         dependencies.append(
                             (related_app_label, related_model_name, None, "model_state")
                         )
@@ -901,6 +930,21 @@ class MigrationAutodetector:
                 old_model_state = self.from_state.models[app_label, old_model_name]
                 new_model_state = self.to_state.models[app_label, model_name]
                 if old_model_state.options.get(option_name) != new_model_state.options.get(option_name):
+                    # Add dependencies for fields that are being removed as part of a
+                    # field type change (e.g., ForeignKey -> ManyToManyField).
+                    # The constraint alteration must happen before the field is removed.
+                    dependencies = []
+                    old_value = old_model_state.options.get(option_name)
+                    if old_value:
+                        for field_names in old_value:
+                            for field_name in field_names:
+                                # If this field exists in old but will be replaced (removed then re-added
+                                # with different type), we need to depend on it still existing
+                                if (app_label, model_name, field_name) in self.old_field_keys:
+                                    old_field = old_model_state.fields.get(field_name)
+                                    new_field = new_model_state.fields.get(field_name)
+                                    if old_field and new_field and type(old_field) != type(new_field):
+                                        dependencies.append((app_label, model_name, field_name, "alter"))
                     self.add_operation(
                         app_label,
                         getattr(operations, operation_name)(
@@ -908,6 +952,7 @@ class MigrationAutodetector:
                             option_name: new_model_state.options.get(option_name),
                             **{option_name: new_model_state.options.get(option_name)},
                         },
+                        dependencies=dependencies,
                     )
 
     def generate_alter_order_with_respect_to(self):
@@ -934,6 +979,25 @@ class MigrationAutodetector:
             new_field = new_model_state.fields.get(field_name)
             if not old_field.is_relation or not new_field.is_relation:
                 continue
+            # Handle case where a field is being replaced (same name, different type)
+            # E.g., ForeignKey -> ManyToManyField. In this case, we need to:
+            # 1. Remove the old field first
+            # 2. Then add the new field
+            # The dependency chain should be: AlterUniqueTogether -> RemoveField -> AddField
+            old_is_fk = isinstance(old_field, models.ForeignKey) if hasattr(models, 'ForeignKey') else (
+                old_field.many_to_many == False and old_field.one_to_one == False and old_field.is_relation
+            )
+            new_is_m2m = new_field.many_to_many if hasattr(new_field, 'many_to_many') else False
+            # This is handled as remove+add, not as an alter
+            if type(old_field) != type(new_field):
+                # Different field types - will be handled by generate_removed_fields
+                # and generate_added_fields, not here
+                # Mark it as a replaced field so proper dependencies are set up
+                if (app_label, model_name) not in self.replaced_fields:
+                    self.replaced_fields[(app_label, model_name)] = set()
+                self.replaced_fields[(app_label, model_name)].add(field_name)
+                continue
             old_rel = old_field.remote_field if hasattr(old_field, 'remote_field') else old_field.rel
             new_rel = new_field.remote_field if hasattr(new_field, 'remote_field') else new_field.rel
             if old_rel.model != new_rel.model:
```

Wait, I need to provide a cleaner, more focused patch based on the actual Django codebase structure. Let me generate a proper patch:

--- a/django/db/migrations/autodetector.py
+++ b/django/db/migrations/autodetector.py
@@ -160,6 +160,7 @@ class MigrationAutodetector:
         self.renamed_models = {}
         self.renamed_models_rel = {}
         self.renamed_fields = {}
+        self.replaced_fields = set()
 
     def _detect_changes(self, convert_apps=None, graph=None):
         """
@@ -217,6 +218,20 @@ class MigrationAutodetector:
             self.old_field_keys.update(
                 (app_label, model_name, field_name) for field_name in old_field_names
             )
+            # Detect fields that exist in both old and new but with incompatible types
+            # (e.g., ForeignKey -> ManyToManyField). These need special handling for
+            # operation ordering.
+            for field_name in old_field_names & new_field_names:
+                old_field = old_model_state.fields[field_name]
+                new_field = new_model_state.fields[field_name]
+                # A ForeignKey changing to ManyToManyField (or vice versa) is not
+                # a simple alteration - it requires remove + add. Track these fields
+                # so we can ensure proper dependency ordering with unique_together.
+                old_is_m2m = old_field.many_to_many if hasattr(old_field, 'many_to_many') else False
+                new_is_m2m = new_field.many_to_many if hasattr(new_field, 'many_to_many') else False
+                if old_is_m2m != new_is_m2m:
+                    self.replaced_fields.add((app_label, model_name, field_name))
+
         self.generate_renamed_fields()
         self.generate_removed_fields()
         self.generate_added_fields()
@@ -900,6 +915,16 @@ class MigrationAutodetector:
                 old_model_state = self.from_state.models[app_label, old_model_name]
                 new_model_state = self.to_state.models[app_label, model_name]
                 if old_model_state.options.get(option_name) != new_model_state.options.get(option_name):
+                    # When removing unique_together that includes a field being replaced
+                    # (e.g., ForeignKey -> ManyToManyField), ensure the operation runs
+                    # before the field removal.
+                    dependencies = []
+                    old_value = old_model_state.options.get(option_name) or set()
+                    for field_names in old_value:
+                        for field_name in field_names:
+                            if (app_label, model_name, field_name) in self.replaced_fields:
+                                dependencies.append((app_label, model_name, field_name, "foo"))
+                                break
                     self.add_operation(
                         app_label,
                         getattr(operations, operation_name)(
@@ -907,6 +932,7 @@ class MigrationAutodetector:
                             option_name: new_model_state.options.get(option_name),
                             **{option_name: new_model_state.options.get(option_name)},
                         },
+                        dependencies=dependencies,
                     )
 
     def generate_alter_order_with_respect_to(self):