I think we should consider this: http://github.com/djspiewak/buildr/commit/51280abe5d37c2800ae53828bc0bb3ba5b51d946
The reason being that JRuby's Kernel#system method is fundamentally broken (because it is based on java.lang.Runtime.exec). They've managed to piece things together so that it's rarely an issue, but problems do surface when doing things like the following: system 'scala' If you run this from JRuby, your terminal will freeze and refuse to accept any input (except for escape sequences like Ctrl+C). This limitation in Kernel#system basically prevents any sort of working REPL support (git:// github.com/djspiewak/buildr.git / interactive-shell). In order to get around this, I propose that Buildr should rewrite the Kernel#system method *when running under JRuby* so that it uses the platform's native `system` function (from the C stdlib). The commit linked above (51280ab) contains the necessary implementation. Note that this commit is basically untested, but it seems to work on Mac for everything I've tried so far. Advantages: Buildr's external process dispatch on JRuby will be more predictable and basically in line with what happens on MRI. This will probably resolve/avoid some bugs and certainly opens up a whole new series of possibilities (like the interactive shell support). Disadvantages: It introduces a new gem dependency on JRuby (ffi-0.3.2) and actually overwrites a core Ruby method. It's the latter that has me the most concerned. Kernel#system is quite foundational to Buildr and Ruby in general, so casually monkey-patching in a new implementation is not a step which should be taken lightly. Thoughts? Daniel
