`mach try` now uses the new lando instance

[Olivier (shtrom) Mehani]

Hi all,

tl;dr: No action needed, this should be transparent. Do report any issue, and bypass with `LANDO_TRY_CONFIG=lando-prod ./mach try`.

As you may be aware, we switched to a new version of Lando just before we started using GitHub for Firefox. Until now, however, all Try pushes were still going through the old Lando instance.

I have just landed some logic that now makes `mach try` use the implementation of Try in new Lando. You don't need to do anything about this.

As added benefits, it should provide better support for patches with weird Unicode characters, a more detailed JSON status API (e.g., https://lando.moz.tools/landing_jobs/36216), and the ability to see the landing queue ahead of your own job, like for normal landing jobs (e.g., https://lando.moz.tools/landings/36216; it is linked as `url` in the JSON status data). The latter still needs a bit of polish, but is essentially functional.

This should be a completely transparent change. However, if you do notice any issue, please report this to https://matrix.to/#/#conduit:mozilla.org (`mach` will remind you of this on every push for some time; so much for transparency, heh).

If you come across a situation where you want to resort to the true-and-tested old Lando for your Try push, you can still force its use by setting `LANDO_TRY_CONFIG=lando-prod` in your environment. For example

    LANDO_TRY_CONFIG=lando-prod ./mach try

We'll soak-test this for a couple of weeks and, barring any major issue, this will become the default-for-good.

CAVEATS:

* This is only for autoland / main for now; we'll backport to ESRs in the `default-for-good` period.

* `mach try perf` still uses the old Lando instance (you may see more Auth0 reauthentication screens when you switch from `try` to `try perf` in the interim; “transparent”, he said).

Enjoy (hopefully)!

--

Olivier Mehani [:shtrom] <ome...@mozilla.com>

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[Olivier (shtrom) Mehani]

Hi all,

More updates on try and new lando.

On Thu, 16 Apr 2026 at 16:35, Olivier (shtrom) Mehani <ome...@mozilla.com> wrote:

* `mach try perf` still uses the old Lando instance (you may see more Auth0 reauthentication screens when you switch from `try` to `try perf` in the interim; “transparent”, he said).

`mach try perf` is now using the new Lando instance by default (thanks to Sparky and Aryx)

This means you shouldn't have to fiddle with LANDO_TRY_CONFIG or removing your `~/.mozbuild/lando_auth0_user_token.json` anymore.

While LANDO_TRY_CONFIG is still supported, we are planning to retire the old lando worker next week.

Please chime in if you have any concern other than `mach try perf` that forced you to rely on LANDO_TRY_CONFIG to hit the old instance.

Thanks!