RFR: JDK-8143296: javac-server/sjavac not compatible with LogFailures on Windows

[Magnus Ihse Bursie]

On 2015-11-19 12:10, Erik Joelsson wrote:
> On Windows, when trying to use the new javac-server mode (or sjavac), 
> each java compilation process that spawns a javac server ends up 
> waiting for that server to shut down before shutting down itself. This 
> behavior is caused by the new LogFailure feature, where each javac 
> invocation is wrapped with our logger.sh script, which in turn uses 
> "tee" to record output to special log files.
>
> It has been a long standing known issue that sjavac on windows has not 
> been compatible with having the automatic build log feature active, 
> for the same reason. This old problem was worked around by simply 
> disabling logging to file when using sjavac on windows. For the 
> LogFailures feature, I would definitely prefer not having to disable it.
>
> It seems that spawning a completely detached background process on 
> Windows can be a bit tricky, especially from java. You need to launch 
> a process with certain flags and settings to the native 
> CreateProcess() call and java.lang.ProcessBuilder is not providing an 
> interface where those flags can be set.
>
> The solution then is to put another native program between the server 
> java and the client java process. We already have one such program, 
> fixpath, and we might as well add a new feature there. I have 
> experimented and found a solution that works by adding a new optional 
> parameter to fixpath "--detach". It launches the child process in 
> detached mode as well as not inheriting handles. It also causes 
> fixpath to exit right after spawning the process instead waiting for 
> an exit code.
>
> Bug: https://bugs.openjdk.java.net/browse/JDK-8143296
> Webrev: http://cr.openjdk.java.net/~erikj/8143296/webrev.01/

The sjavac code is a bit tricky to follow, but your changes look good to me.

/Magnus