As a test I removed the following as the note describes, recompiled and watch is working again.
# TODO: Remove when dart-sass will exit when stdin is closed.
# Link: https://github.com/sass/dart-sass/pull/1411
path =
if "--watch" in args and platform() != :windows do
[script_path() | path]
else
path
end
This is now a much shorter message than the one I had written about watch not working for dart-sass >= 1.50.0
https://github.com/CargoSense/dart_sass/blob/main/lib/dart_sass.ex#L189
As a test I removed the following as the note describes, recompiled and watch is working again.
https://github.com/sass/dart-sass/releases/tag/1.50.0
It looks like you can go ahead and make these changes for watch now.
Thanks