Rename migration files when renaming migration class

lib/ruby_lsp/ruby_lsp_rails/addon.rb

@@ -16,6 +16,7 @@
 require_relative "definition"
 require_relative "rails_test_style"
 require_relative "completion"
+require_relative "rename"
 require_relative "indexing_enhancement"
 
 module RubyLsp
@@ -138,6 +139,14 @@ def create_completion_listener(response_builder, node_context, dispatcher, uri)
         Completion.new(@rails_runner_client, response_builder, node_context, dispatcher, uri)
       end
 
+      # @override
+      #: (String fully_qualified_name, String new_name, Array[(Interface::RenameFile | Interface::TextDocumentEdit)] document_changes) -> void
+      def collect_file_renames(fully_qualified_name, new_name, document_changes)
+        return unless @global_state
+
+        Rename.new(@global_state.index, fully_qualified_name, new_name, document_changes)
+      end
+
       #: (Array[{uri: String, type: Integer}] changes) -> void
       def workspace_did_change_watched_files(changes)
         if changes.any? { |c| c[:uri].end_with?("db/schema.rb") || c[:uri].end_with?("structure.sql") }

lib/ruby_lsp/ruby_lsp_rails/rename.rb

@@ -0,0 +1,41 @@
+# typed: strict
+# frozen_string_literal: true
+
+module RubyLsp
+  module Rails
+    class Rename
+      #: (RubyIndexer::Index index, String fully_qualified_name, String new_name, Array[(Interface::RenameFile | Interface::TextDocumentEdit)] document_changes) -> void
+      def initialize(index, fully_qualified_name, new_name, document_changes)
+        index[fully_qualified_name]&.each do |entry|
+          file_path = entry.uri.full_path
+          next unless file_path
+
+          next unless file_path.include?("/db/migrate/")
+
+          old_file_name = entry.file_name
+          old_snake = file_from_constant_name(entry.name.split("::").last)
+
+          next unless old_file_name.match?(/\A\d+_#{Regexp.escape(old_snake)}\.rb\z/)
+
+          timestamp_prefix = old_file_name.delete_suffix("_#{old_snake}.rb")
+          new_snake = file_from_constant_name(new_name.split("::").last)
+
+          new_uri = URI::Generic.from_path(
+            path: File.join(File.dirname(file_path), "#{timestamp_prefix}_#{new_snake}.rb"),
+          ).to_s
+
+          document_changes << Interface::RenameFile.new(kind: "rename", old_uri: entry.uri.to_s, new_uri: new_uri)
+        end
+      end
+
+      private
+
+      #: (String constant_name) -> String
+      def file_from_constant_name(constant_name)
+        constant_name
+          .gsub(/([a-z])([A-Z])|([A-Z])([A-Z][a-z])/, '\1\3_\2\4')
+          .downcase
+      end
+    end
+  end
+end

test/ruby_lsp_rails/rename_test.rb

@@ -0,0 +1,65 @@
+# typed: true
+# frozen_string_literal: true
+
+require "test_helper"
+
+module RubyLsp
+  module Rails
+    class RenameTest < ActiveSupport::TestCase
+      test "renames migration file to match new class name" do
+        document_changes = collect_file_renames(
+          "#{dummy_root}/db/migrate/20210901000000_create_foos.rb",
+          "class CreateFoos < ActiveRecord::Migration[7.0]; end",
+          "CreateFoos",
+          "CreateBars",
+        )
+
+        assert_equal(1, document_changes.size)
+        rename = document_changes.first
+        assert_instance_of(Interface::RenameFile, rename)
+        assert_equal(
+          URI::Generic.from_path(path: "#{dummy_root}/db/migrate/20210901000000_create_foos.rb").to_s,
+          rename.old_uri,
+        )
+        assert_equal(
+          URI::Generic.from_path(path: "#{dummy_root}/db/migrate/20210901000000_create_bars.rb").to_s,
+          rename.new_uri,
+        )
+      end
+
+      test "does nothing for non-migration files" do
+        document_changes = collect_file_renames(
+          "#{dummy_root}/app/models/foo.rb",
+          "class Foo < ApplicationRecord; end",
+          "Foo",
+          "Bar",
+        )
+
+        assert_empty(document_changes)
+      end
+
+      test "does nothing when file name does not match class name" do
+        document_changes = collect_file_renames(
+          "#{dummy_root}/db/migrate/20210901000000_something_else.rb",
+          "class CreateFoos < ActiveRecord::Migration[7.0]; end",
+          "CreateFoos",
+          "CreateBars",
+        )
+
+        assert_empty(document_changes)
+      end
+
+      private
+
+      def collect_file_renames(file_path, source, old_name, new_name)
+        index = RubyIndexer::Index.new
+        uri = URI::Generic.from_path(path: file_path)
+        index.index_single(uri, source)
+
+        document_changes = []
+        Rename.new(index, old_name, new_name, document_changes)
+        document_changes
+      end
+    end
+  end
+end