tl;dr
https://hg.mozilla.org/mozilla-central/rev/71075a6e5d4d needs to
be in your tree or buildbot builds will soon fail.
https://bugzilla.mozilla.org/show_bug.cgi?id=748490 created the concept
"testing JS modules." These are JavaScript files that can be
loaded/imported as modules but are only available in testing code, not
in released packages. While I'm mentioning it, I should say that you
should consider using this instead of "head" files to provide common
functionality to your test code because it is an architecturally
superior solution.
https://developer.mozilla.org/en/Developing_Tests#JavaScript_Test-Only_Modules
has more.
To support this new feature, we need to package these test files in the
tests archive produced during packaging. And, we need to configure
buildbot to extract this directory when it runs tests.
Unfortunately, because of the way things work, if the "modules"
directory is missing from the tests package and buildbot tries to
extract this directory, the command will return a non-0 exit code and
the build step will fail. In
https://bugzilla.mozilla.org/show_bug.cgi?id=755339, we added an empty
"modules" directory to the tests archive. And, that trivial changeset
(
https://hg.mozilla.org/mozilla-central/rev/71075a6e5d4d) has been
pushed out to central, inbound, aurora, beta, esr, and release.
Sometime in the near future, buildbot will be updated
(
https://bugzilla.mozilla.org/show_bug.cgi?id=757460). Once it is, if
the tree being built does not produce test archives with the "modules"
directory, things will fail when extracting the tests archive.
So, to prevent build breakage, you'll need to ensure your tree picks up
71075a6e5d4d from mozilla-central. If you do nothing, your tree may
appear to break randomly (when buildbot updated are deployed).
Yes, everyone realizes this is a silly hoop to jump through. There are
comments in bug 757460 regarding how this could be eliminated in the
future. They are out of scope for this task, however.
If you have any questions, please direct them to bug 757460.
Gregory/gps