fix: correct order, when renaming attribute with an identity (#533)

Author: artiom

lib/migration_generator/migration_generator.ex

@@ -1474,6 +1474,21 @@ defmodule AshPostgres.MigrationGenerator do
     false
   end
 
+  defp after?(
+         %Operation.RenameAttribute{
+           old_attribute: %{source: source},
+           table: table,
+           schema: schema
+         },
+         %Operation.RemoveUniqueIndex{
+           identity: %{keys: keys},
+           table: table,
+           schema: schema
+         }
+       ) do
+    source in List.wrap(keys)
+  end
+
   defp after?(
          %Operation.RemoveUniqueIndex{table: table, schema: schema},
          %{table: table, schema: schema}
@@ -1701,6 +1716,19 @@ defmodule AshPostgres.MigrationGenerator do
     destination_attribute in keys
   end
 
+  defp after?(
+         %Operation.AlterAttribute{
+           old_attribute: %{
+             source: source
+           },
+           table: table,
+           schema: schema
+         },
+         %Operation.RemoveUniqueIndex{identity: %{keys: keys}, table: table, schema: schema}
+       ) do
+    source in List.wrap(keys)
+  end
+
   defp after?(
          %Operation.AlterAttribute{
            new_attribute: %{references: %{table: table, destination_attribute: source}}

test/migration_generator_test.exs

@@ -1062,6 +1062,83 @@ defmodule AshPostgres.MigrationGeneratorTest do
       assert File.read!(file2) =~ ~S[rename table(:posts), :subject, to: :title]
     end
 
+    test "when renaming a field with an identity, it asks which field you are renaming it to, and updates indexes in the correct order" do
+      defposts do
+        identities do
+          identity(:subject, [:subject])
+        end
+
+        attributes do
+          uuid_primary_key(:id)
+          attribute(:subject, :string, public?: true)
+        end
+      end
+
+      defdomain([Post])
+
+      send(self(), {:mix_shell_input, :yes?, true})
+      send(self(), {:mix_shell_input, :prompt, "subject"})
+
+      AshPostgres.MigrationGenerator.generate(Domain,
+        snapshot_path: "test_snapshots_path",
+        migration_path: "test_migration_path",
+        quiet: true,
+        format: false
+      )
+
+      assert [_file1, file2] =
+               Enum.sort(Path.wildcard("test_migration_path/**/*_migrate_resources*.exs"))
+               |> Enum.reject(&String.contains?(&1, "extensions"))
+
+      contents = File.read!(file2)
+      [up_side, down_side] = String.split(contents, "def down", parts: 2)
+
+      up_side_parts =
+        String.split(up_side, "\n", trim: true)
+        |> Enum.map(&String.trim/1)
+
+      drop_index =
+        Enum.find_index(up_side_parts, fn x ->
+          x == "drop_if_exists unique_index(:posts, [:title], name: \"posts_title_index\")"
+        end)
+
+      rename_table =
+        Enum.find_index(up_side_parts, fn x ->
+          x == "rename table(:posts), :title, to: :subject"
+        end)
+
+      create_index =
+        Enum.find_index(up_side_parts, fn x ->
+          x == "create unique_index(:posts, [:subject], name: \"posts_subject_index\")"
+        end)
+
+      assert drop_index < rename_table
+      assert rename_table < create_index
+
+      down_side_parts =
+        String.split(down_side, "\n", trim: true)
+        |> Enum.map(&String.trim/1)
+
+      drop_index =
+        Enum.find_index(down_side_parts, fn x ->
+          x ==
+            "drop_if_exists unique_index(:posts, [:subject], name: \"posts_subject_index\")"
+        end)
+
+      rename_table =
+        Enum.find_index(down_side_parts, fn x ->
+          x == "rename table(:posts), :subject, to: :title"
+        end)
+
+      create_index =
+        Enum.find_index(down_side_parts, fn x ->
+          x == "create unique_index(:posts, [:title], name: \"posts_title_index\")"
+        end)
+
+      assert drop_index < rename_table
+      assert rename_table < create_index
+    end
+
     test "when renaming a field, it asks which field you are renaming it to, and adds it if you arent" do
       defposts do
         attributes do