Recently, builds that poll Bitbucket using mercurial stopped working. The polling never triggers a build. Triggering these builds manually works no problem, so mercurial is working.

The poll line looks like:

H/5 * * * *

The poll log says the following:

Started on Oct 4, 2013 12:06:35 PM
Polling SCM changes on master
[staging] $ hg pull --rev staging
remote: /bin/sh: ssh: command not found
abort: no suitable response from remote hg!
[staging] $ hg log --rev staging --template

[staging] $ hg log --rev staging --template

Done. Took 0.48 sec
No changes

This machine absolutely has SSH and Mercurial installed (manual builds work).

Jenkins 1.533
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