We've had a few bugs filed /IRC debugging sessions over the months that turned out to be due to people's Vagrant environment not being up to date (ie `vagrant provision` not run recently; eg bug 1420918). Sadly Vagrant doesn't have any in-built functionality for warning if provision hasn't been run recently, but perhaps we could make our own in the bash profile login script (or even just run provision automatically if > N days/weeks). (It's worth noting this is another pain point that we wouldn't have if we were using Docker/Docker Compose - bug 1169263)

I've had a look into doing this, but the options aren't great - we should just do bug 1169263.

Joel hit this again today. I had an idea - let's just update the docs to always say to use `vagrant up --provision` rather than just `vagrant up`. Whilst the former is redundant for new users, it's likely those returning after a gap will refer back to those docs and end up running provision without needing to remember to :-)

Commit pushed to master at https://github.com/mozilla/treeherder https://github.com/mozilla/treeherder/commit/70e9cdc91d227bcf25fc0f38783728e892e7dfae Bug 1420941 - Docs: Encourage users to run Vagrant provision (#3539) The `--provision` flag is unnecessary for new instances, since Vagrant runs `provision` as part of the initial `up` regardless. However by including `--provision` in the suggested command, it will mean returning contributors will re-run provision when they re-use the same steps. An alternative approach would be to mark the provision block in `Vagrantfile` as `run: "always"`, however that would slow down the `vagrant up` of core developers too (by 40s), with no way to opt-out.