Projects in the mounted WSL filesystem

[stellerex]

Latest versions of Mill doesn't support projects located in the mounted WSL filesystem. The core issue is microsoft/WSL#5762.

java.io.IOException: Incorrect function
        at java.base/sun.nio.ch.FileDispatcherImpl.lock0(Native Method)
        at java.base/sun.nio.ch.FileDispatcherImpl.lock(FileDispatcherImpl.java:107)
        at java.base/sun.nio.ch.FileChannelImpl.tryLock(FileChannelImpl.java:1529)
        at java.base/java.nio.channels.FileChannel.tryLock(FileChannel.java:1360)
        at mill.main.client.lock.FileLock.tryLock(FileLock.java:24)
        at mill.main.client.ServerLauncher.acquireLocksAndRun(ServerLauncher.java:99)
        at mill.runner.client.MillClientMain.main(MillClientMain.java:65)

It would be nice to add an option to skip locking.

[lefou]

Or we support alternative location for lock files.

[lihaoyi]

@stellerex does passing in the flag --no-build-lock work around the problem?

[stellerex]

@stellerex does passing in the flag --no-build-lock work around the problem?

Yes, in combination with --no-server. Thank you!

[lihaoyi]

Great! I had overlooked --no-server, which is necessary because Mill uses file locks for mutex as part of starting up the background daemon to ensure only one daemon gets spawned

I think you may also be able to override MILL_OUTPUT_DIR to move the out folder somewhere else not on the mounted filesystem, which would also workaround the problem since the locks are placed within the out folder. That may allow you to avoid the performance hit of using --no-server all the time