Bugzilla

You'll need to make sure your task:
A) Has a `variants` key that includes "fission"
B) Sets `fission-run-on-projects` (this is the same as `run-on-projects` but only applies to fission tasks)

Is remote(pup) a `test` task? If so enabling the fission variant will pass:
```
            'mozharness': {
                'extra-options': ['--setpref=fission.autostart=true',
                                  '--setpref=dom.serviceWorkers.parent_intercept=true',
                                  '--setpref=browser.tabs.documentchannel=true'],
            },
```

Note this goes into mozharness not the mach command. If your harness supports `--setpref` I'd recommend making `--enable-fission` a simple alias to the above, and then updating your internal logic to look for the `fission.autostart` pref to determine whether or not it is running with fission.

If your harness doesn't support `--setpref` or it is not a `test` kind, you're off the beaten path and will need to figure out some other way of hooking it all up properly.

Is remote(pup) a `test` task? If so you'll need to make sure your task:
A) Has a `variants` key that includes "fission"
B) Sets `fission-run-on-projects` (this is the same as `run-on-projects` but only applies to fission tasks)

Enabling the fission variant will pass:
```
            'mozharness': {
                'extra-options': ['--setpref=fission.autostart=true',
                                  '--setpref=dom.serviceWorkers.parent_intercept=true',
                                  '--setpref=browser.tabs.documentchannel=true'],
            },
```

Note this goes into mozharness not the mach command. If your harness supports `--setpref` I'd recommend making `--enable-fission` a simple alias to the above, and then updating your internal logic to look for the `fission.autostart` pref to determine whether or not it is running with fission.

If your harness doesn't support `--setpref` or it is not a `test` kind, you're off the beaten path and will need to figure out some other way of hooking it all up properly.