First run of template project fails with WatchfilesRustInternalError

[bertbarabas]

Describe the bug
WatchfilesRustInternalError exception occurs immediately after the first init/run of the sidebar template.
Exception does not occur on subsequent runs
The exception doesn't stop the app from working. I.e. I can view the app at http://localhost:3000/

To Reproduce
Steps to reproduce the behavior:

• on a brand new folder
• install reflex
• reflex init (and pick sidebar template)
• reflex run
  EXCEPTION:
• _rust_notify.WatchfilesRustInternalError: error in underlying watcher: IO error for operation on /home/bert_barabas/reflexapp/.web/nocompile: No such file or directory (os error 2) about ["/home/bert_barabas/reflexapp/.web/nocompile"]

Expected behavior
No exception

Screenshots
If applicable, add screenshots to help explain your problem.

Specifics (please complete the following information):

• Python Version: 3.12.1
• Reflex Version: v0.4.3
• OS: WSL on Windows 11 (Ubuntu 22.04.4 LTS (GNU/Linux 5.15.133.1-microsoft-standard-WSL2 x86_64)
• Browser (Optional):

Additional context
Exception Stack.txt

Add any other context about the problem here.

[picklelo]

Thanks for reporting - so running it again solves the issue?

Seems like some misconfiguration in our uvicorn on Windows - we shouldn't be watching the .web folder, only the main app folder for reloads...

Perhaps we need to explicitly set the watch dir. If anyone has any ideas, would welcome a fix here

[bertbarabas]

Thanks for reporting - so running it again solves the issue?

Correct, the exception only happens on the first "Reflex run".

[bertbarabas]

Just saw the exception happen again but this time after it had been running a while. So it looks like while this exception happens every time when executing "reflex run" for the very first time on a project, it can also very rarely happen in other cases.

[tsdaemon]

Weird, but I am having the same error quite often on the latest version (0.5.9):

_rust_notify.WatchfilesRustInternalError: error in underlying watcher: IO error for operation on /home/tsdaemon/ascension/knw/.web/nocompile: No such file or directory (os error 2) about ["/home/tsdaemon/ascension/knw/.web/nocompile"]

[tsdaemon]

Ok, its not exactly the reflex problem. It can only be solved in uvicorn. See the class definition there:

class WatchFilesReload(BaseReload):
    def __init__(
        self,
        config: Config,
        target: Callable[[list[socket] | None], None],
        sockets: list[socket],
    ) -> None:
        super().__init__(config, target, sockets)
        self.reloader_name = "WatchFiles"
        self.reload_dirs = []
        for directory in config.reload_dirs:
            if Path.cwd() not in directory.parents:
                self.reload_dirs.append(directory)
        if Path.cwd() not in self.reload_dirs:
            self.reload_dirs.append(Path.cwd())

        self.watch_filter = FileFilter(config)
        import pdb

        pdb.set_trace()
        self.watcher = watch(
            *self.reload_dirs,
            watch_filter=None,
            stop_event=self.should_exit,
            # using yield_on_timeout here mostly to make sure tests don't
            # hang forever, won't affect the class's behavior
            yield_on_timeout=True,
        )

    def should_restart(self) -> list[Path] | None:
        self.pause()

        changes = next(self.watcher)
        if changes:
            unique_paths = {Path(c[1]) for c in changes}
            return [p for p in unique_paths if self.watch_filter(p)]
        return None

Even if you set excluded folders, it does not exclude them from watcher: it just ignores them. So if watcher fails, it fails. And for some reason it watches all files in the directory, even if you told it only to watch the code folder. It quite implicit, and bad approach IMHO.

[tsdaemon]

The problem is listed in uvicorn repository: encode/uvicorn#1785