feat: support polling instead of fs events when watching

Polling was added upstream in 3.1.0.

Suggested by #168

CHANGELOG.md

@@ -2,7 +2,8 @@
 ## Unreleased
 
 * Correctly handle paths with embedded spaces. [#184](https://github.com/rails/tailwindcss-rails/issues/184) by [@flavorjones](https://github.com/flavorjones)
-* Rake tasks accept a `debug` argument to generate unminified assets, e.g. `tailwindcss:build[debug]`. [#198](https://github.com/rails/tailwindcss-rails/pull/198) by [@flavorjones](https://github.com/flavorjones)
+* The `build` and `watch` tasks accept a `debug` argument to generate unminified assets: `rails tailwindcss:build[debug]` or `rails tailwindcss:watch[debug]`. [#198](https://github.com/rails/tailwindcss-rails/pull/198) by [@flavorjones](https://github.com/flavorjones)
+* The `watch` task accepts a `poll` argument to use polling instead of file system events: `rails tailwindcss:watch[poll]`. [#199](https://github.com/rails/tailwindcss-rails/pull/199) by [@flavorjones](https://github.com/flavorjones)
 
 
 ## v2.0.12 / 2022-08-10

README.md

@@ -40,10 +40,15 @@ While you're developing your application, you want to run Tailwind in "watch" mo
 
 If you are running `rails tailwindcss:watch` as a process in a Docker container, set `tty: true` in `docker-compose.yml` for the appropriate container to keep the watch process running.
 
+If you are running `rails tailwindcss:watch` on a system that doesn't fully support file system events, pass a `poll` argument to the task to instruct tailwindcss to instead use polling: `rails tailwindcss:watch[poll]`. If you use `bin/dev` then you should modify your `Procfile.dev`.
+
+
 ### Debugging with unminified assets
 
 If you want unminified assets, you can pass a `debug` argument to the rake task, i.e. `rails tailwindcss:build[debug]` or `rails tailwindcss:watch[debug]`.
 
+Note that you can combine task options, e.g. `rails tailwindcss:watch[debug,poll]`.
+
 
 ### Custom inputs or outputs
 

lib/tailwindcss/commands.rb

@@ -66,8 +66,11 @@ def compile_command(debug: false, **kwargs)
         end
       end
 
-      def watch_command(**kwargs)
-        compile_command(**kwargs) << "-w"
+      def watch_command(poll: false, **kwargs)
+        compile_command(**kwargs).tap do |command|
+          command << "-w"
+          command << "-p" if poll
+        end
       end
     end
   end

lib/tasks/build.rake

@@ -10,7 +10,8 @@ namespace :tailwindcss do
   desc "Watch and build your Tailwind CSS on file changes"
   task :watch do |_, args|
     debug = args.extras.include?("debug")
-    command = Tailwindcss::Commands.watch_command(debug: debug)
+    poll = args.extras.include?("poll")
+    command = Tailwindcss::Commands.watch_command(debug: debug, poll: poll)
     puts command.inspect
     system(*command)
   end

test/lib/tailwindcss/commands_test.rb

@@ -65,13 +65,22 @@ def mock_exe_directory(platform)
         assert_kind_of(Array, actual)
         assert_equal(executable, actual.first)
         assert_includes(actual, "-w")
+        refute_includes(actual, "-p")
         assert_includes(actual, "--minify")
 
         actual = Tailwindcss::Commands.watch_command(exe_path: dir, debug: true)
         assert_kind_of(Array, actual)
         assert_equal(executable, actual.first)
         assert_includes(actual, "-w")
+        refute_includes(actual, "-p")
         refute_includes(actual, "--minify")
+
+        actual = Tailwindcss::Commands.watch_command(exe_path: dir, poll: true)
+        assert_kind_of(Array, actual)
+        assert_equal(executable, actual.first)
+        assert_includes(actual, "-w")
+        assert_includes(actual, "-p")
+        assert_includes(actual, "--minify")
       end
     end
   end