Differentiate by Mill version when selecting a server worker

[lefou]

In older Mill versions, we tried to detect when the Mill version changed. In that case, we stopped the server process and started a new one. This server stopping worked unrelieble and is currently not working at all.

This pragmatic change simply does not try to re-use a mill server process when the Mill version does not match. Instead, we only choose between instances with the exact version or start a new instance. This is identical to the beavior, when we run with a differnet JVM.

Resource wise, we potentially increase the amount of running processes, but we do this anyways in other situations. Also, idle Mill servers stop themselves after a some time span.

[lihaoyi]

Looks fine. Should we leave the mill version un-hashes? Might make it easier to inspect and see what's going on if the mill version was in plaintext as part lf the file path

[lefou]

Looks fine. Should we leave the mill version un-hashes? Might make it easier to inspect and see what's going on if the mill version was in plaintext as part lf the file path

Would be fine by me. That was actually my first approach, but the resulting name was rather long. For more insights, we could also leave some info as file in the directory, e.g. start time, Mill version, Java details, maybe even a history of executed tasks.

[lefou]

For some reasons, I always get an exception, when I include the plain Mill version in the Mill worker directory:

-        String versionAndJvmHomeEncoding = Util.sha1Hash(BuildInfo.millVersion + System.getProperty("java.home"));
+        final String versionAndJvmHomeEncoding = BuildInfo.millVersion + "-" + Util.sha1Hash(System.getProperty("java.home"));
+        System.err.println("==> " + versionAndJvmHomeEncoding);

MILL_VERSION=0.11.1-3-d55c29-DIRTY34f18ee7 mill resolve _
==> 0.11.1-3-d55c29-DIRTY34f18ee7-jI8OnFgMTiLMP+r5K66NDMQ65lc=
Exception in thread "main" java.net.SocketException: Datei oder Verzeichnis nicht gefunden
        at org.newsclub.net.unix.NativeUnixSocket.bind(Native Method)
        at org.newsclub.net.unix.AFSocketImpl.bind(AFSocketImpl.java:336)
        at org.newsclub.net.unix.AFServerSocket.bind(AFServerSocket.java:257)
        at java.base/java.net.ServerSocket.bind(ServerSocket.java:349)
        at org.newsclub.net.unix.AFServerSocket.bindOn(AFServerSocket.java:176)
        at org.newsclub.net.unix.AFUNIXServerSocket.bindOn(AFUNIXServerSocket.java:87)
        at mill.runner.Server.$anonfun$run$2(MillServerMain.scala:107)
        at scala.runtime.java8.JFunction0$mcV$sp.apply(JFunction0$mcV$sp.scala:18)
        at mill.runner.Server$.lockBlock(MillServerMain.scala:231)
        at mill.runner.Server.$anonfun$run$1(MillServerMain.scala:102)
        at scala.runtime.java8.JFunction0$mcV$sp.apply(JFunction0$mcV$sp.scala:18)
        at mill.runner.Server$.tryLockBlock(MillServerMain.scala:239)
        at mill.runner.Server.run(MillServerMain.scala:99)
        at mill.runner.MillServerMain$.main(MillServerMain.scala:60)
        at mill.runner.MillServerMain.main(MillServerMain.scala)
Exception in thread "main" java.lang.Exception: Failed to connect to server
        at mill.main.client.MillClientMain.run(MillClientMain.java:197)
        at mill.main.client.MillClientMain.main0(MillClientMain.java:123)
        at mill.main.client.MillClientMain.main(MillClientMain.java:71)
Caused by: java.net.SocketException: 
        at org.newsclub.net.unix.NativeUnixSocket.connect(Native Method)
        at org.newsclub.net.unix.AFSocketImpl.connect0(AFSocketImpl.java:393)
        at org.newsclub.net.unix.AFSocket.connect0(AFSocket.java:267)
        at org.newsclub.net.unix.AFSocket.connect(AFSocket.java:236)
        at org.newsclub.net.unix.AFSocket.connect(AFSocket.java:231)
        at org.newsclub.net.unix.AFSocket.connectTo(AFSocket.java:179)
        at org.newsclub.net.unix.AFUNIXSocket.connectTo(AFUNIXSocket.java:109)
        at mill.main.client.MillClientMain.run(MillClientMain.java:189)
        ... 2 more

Maybe the dots. I don't know. To keep things simple, I will just keep it in the hashed form, which works as expected.