au run --watch doesn't detect file changes in some cases

[Gimly]

I'm submitting a bug report

• Library Version:
  Aurelia cli 0.32.0

Please tell us about your environment:

• Operating System:
  Linux (Debian Jessie inside Docker container), Windows 10 (Docker Host)

• Node Version:
  8.9.1

• NPM Version:
  5.5.1

• Browser:
  all

• Language:
  TypeScript 2.6

• Loader/bundler:
  RequireJS

Current behavior:
I'm testing Aurelia, and since I didn't want to install too much things directly on my machine, I decided to try to create a Docker image for development with Aurelia. I based it upon Debian Jessie and installed all the necessary dependencies to get Aurelia CLI working (Git, NodeJs, NPM).

I have linked the ports (9000 and 3001) of the Docker image to the same ports on my Windows 10 host, and created a volume in the Docker image that is linked to a local folder in the host. I then created a new Aurelia project using au new inside of the volume used by the Docker image. This way, I can access the app code from my local machine as well as from the Docker image.

When I start the app with au run --env dev --watch, it builds and I can access it fine by going to localhost:9000 from my local machine. If I modify a file directly from the Docker image (using vi for example), it detects that the file changed and triggers a rebuild, and I see the changes in the page directly.

However, if I change the files from the host, the watcher doesn't see that a file has changed and doesn't trigger the build. I can see that the file has changed on the Docker image, and that the "modified date" was updated, but the watcher doesn't see it. If I simply touch filename, then the watcher triggers a rebuilds and serves the new file.

• What is the expected behavior?

I would expect the watcher to detect the file change, even if it's coming from the host.

[JeroenVinke]

Could you provide a repository that has this setup? That would make it easier to start debugging

[ccrd]

I had a similar issue observing file changes in a samba mount. Adding usePolling to gulp.watch configuration solved it.

...
gulp.watch(project.transpiler.source, { 
        usePolling: true // Polling enables file watching on samba shares  
}, refresh).on('change', onChange);  
...

[3cp]

This is likely a limitation from chokidar (which gulp-watch uses) instead of aurelia-cli.

paulmillr/chokidar#242

The solution is similar to @ccrd suggested, just use polling.

[Alexander-Taran]

documentation
help_needed

edge case with watching not real file system

[JeroenVinke]

added this to #787