I have a Windows master node and Mac slave node.

I installed Mercurial 2.3 myself on the Mac. The installer outputs the binaries into /usr/local/bin which is on my PATH. Invoking "hg" in a local terminal or over SSH (from Windows) works fine. However, when I run a task on the Mac that uses Mercurial I get:

Building remotely on MacOS X 10.7 in workspace <workspace> JDK installation skipped: Unknown CPU name: mac os x $ hg clone --rev default --noupdate <repository> <workspace>
ERROR: Failed to clone <repository> because hg could not be found; check that you've properly configured your Mercurial installation
ERROR: Failed to clone <repository>

I suspect this is failing because Jenkins is configured to auto-install Mercurial to "INSTALLATION/bin/hg" and run it from there but it does not because (apparently) Mercurial auto-installation is not supported for OSX.

Expected behavior: Invoke "hg" off the PATH on platforms that do not support auto-installer.