From a098cde9683a560bfc4b22f9b2581cf8cedc7dab Mon Sep 17 00:00:00 2001
From: David Wobrock <david.wobrock@gmail.com>
Date: Wed, 11 May 2022 16:05:50 +0200
Subject: [PATCH] Refs #27064 -- Refactored out
 MigrationAutodetector.create_renamed_fields().

---
 django/db/migrations/autodetector.py | 84 +++++++++++++++++++---------
 1 file changed, 59 insertions(+), 25 deletions(-)

diff --git a/django/db/migrations/autodetector.py b/django/db/migrations/autodetector.py
index 0616ea4dbe..00e04fd799 100644
--- a/django/db/migrations/autodetector.py
+++ b/django/db/migrations/autodetector.py
@@ -122,6 +122,7 @@ class MigrationAutodetector:
         self.generated_operations = {}
         self.altered_indexes = {}
         self.altered_constraints = {}
+        self.renamed_fields = {}
 
         # Prepare some old/new state and model lists, separating
         # proxy models and ignoring unmigrated apps.
@@ -169,6 +170,11 @@ class MigrationAutodetector:
         self.generate_altered_options()
         self.generate_altered_managers()
 
+        # Create the renamed fields and store them in self.renamed_fields.
+        # They are used by create_altered_indexes(), generate_altered_fields(),
+        # generate_removed_altered_index/unique_together(), and
+        # generate_altered_index/unique_together().
+        self.create_renamed_fields()
         # Create the altered indexes and store them in self.altered_indexes.
         # This avoids the same computation in generate_removed_indexes()
         # and generate_added_indexes().
@@ -907,11 +913,12 @@ class MigrationAutodetector:
                 ),
             )
 
-    def generate_renamed_fields(self):
+    def create_renamed_fields(self):
         """Work out renamed fields."""
-        self.renamed_fields = {}
+        self.renamed_operations = []
+        old_field_keys = self.old_field_keys.copy()
         for app_label, model_name, field_name in sorted(
-            self.new_field_keys - self.old_field_keys
+            self.new_field_keys - old_field_keys
         ):
             old_model_name = self.renamed_models.get(
                 (app_label, model_name), model_name
@@ -922,7 +929,7 @@ class MigrationAutodetector:
             # Scan to see if this is actually a rename!
             field_dec = self.deep_deconstruct(field)
             for rem_app_label, rem_model_name, rem_field_name in sorted(
-                self.old_field_keys - self.new_field_keys
+                old_field_keys - self.new_field_keys
             ):
                 if rem_app_label == app_label and rem_model_name == model_name:
                     old_field = old_model_state.get_field(rem_field_name)
@@ -947,37 +954,64 @@ class MigrationAutodetector:
                         if self.questioner.ask_rename(
                             model_name, rem_field_name, field_name, field
                         ):
-                            # A db_column mismatch requires a prior noop
-                            # AlterField for the subsequent RenameField to be a
-                            # noop on attempts at preserving the old name.
-                            if old_field.db_column != field.db_column:
-                                altered_field = field.clone()
-                                altered_field.name = rem_field_name
-                                self.add_operation(
+                            self.renamed_operations.append(
+                                (
+                                    rem_app_label,
+                                    rem_model_name,
+                                    old_field.db_column,
+                                    rem_field_name,
                                     app_label,
-                                    operations.AlterField(
-                                        model_name=model_name,
-                                        name=rem_field_name,
-                                        field=altered_field,
-                                    ),
+                                    model_name,
+                                    field,
+                                    field_name,
                                 )
-                            self.add_operation(
-                                app_label,
-                                operations.RenameField(
-                                    model_name=model_name,
-                                    old_name=rem_field_name,
-                                    new_name=field_name,
-                                ),
                             )
-                            self.old_field_keys.remove(
+                            old_field_keys.remove(
                                 (rem_app_label, rem_model_name, rem_field_name)
                             )
-                            self.old_field_keys.add((app_label, model_name, field_name))
+                            old_field_keys.add((app_label, model_name, field_name))
                             self.renamed_fields[
                                 app_label, model_name, field_name
                             ] = rem_field_name
                             break
 
+    def generate_renamed_fields(self):
+        """Generate RenameField operations."""
+        for (
+            rem_app_label,
+            rem_model_name,
+            rem_db_column,
+            rem_field_name,
+            app_label,
+            model_name,
+            field,
+            field_name,
+        ) in self.renamed_operations:
+            # A db_column mismatch requires a prior noop AlterField for the
+            # subsequent RenameField to be a noop on attempts at preserving the
+            # old name.
+            if rem_db_column != field.db_column:
+                altered_field = field.clone()
+                altered_field.name = rem_field_name
+                self.add_operation(
+                    app_label,
+                    operations.AlterField(
+                        model_name=model_name,
+                        name=rem_field_name,
+                        field=altered_field,
+                    ),
+                )
+            self.add_operation(
+                app_label,
+                operations.RenameField(
+                    model_name=model_name,
+                    old_name=rem_field_name,
+                    new_name=field_name,
+                ),
+            )
+            self.old_field_keys.remove((rem_app_label, rem_model_name, rem_field_name))
+            self.old_field_keys.add((app_label, model_name, field_name))
+
     def generate_added_fields(self):
         """Make AddField operations."""
         for app_label, model_name, field_name in sorted(