I'm pulling it off the stack.
buildscript {
def root = file('.').toString();
// We have to seek through, since groovy/gradle introduces
// a lot of abstraction that we see in the trace as extra frames.
// Fortunately, the first frame in the build dir is always going
// to be this script.
buildscript.metaClass.__script__ = file(
Thread.currentThread().stackTrace.find { ste ->
ste.fileName?.startsWith root
}.fileName
)
// later, still in buildscript
def libDir = "${buildscript.__script__.parent}/lib"
classpath files("${libDir}/custom-plugin.jar")
}
// This is important to do if you intend to use this path outside of
// buildscript{}, since everything else is pretty asynchronous, and
// they all share the buildscript object.
def __buildscripts__ = buildscript.__script__.parent;
Compact version for those who don't like clutter:
String r = file('.').toString();
buildscript.metaClass.__script__ = file(Thread.currentThread().stackTrace*.fileName?.find { it.startsWith r })