Proposal: Allow Gatherers to Opt-out of Lighthouse Filtering about lighthouse

[connorjclark]

I believe we landed on this because it avoided landing a non-reversible change to the gatherer implementation that affects filtering, which is already kinda complex. But this doesn't help for custom gatherers.

We also have --disable-full-page-screenshot to exclude this logic for the FPS audit ... so a gatherer option called alwaysRun: true would be more like alwaysRunUnlessToldOtherwise :p Maybe runOnlyWhenRequested or runOnlyIfNeeded: false or supplementary: true ...

Is it an option for you to always include (via --only-audits) a hidden audit that depends on your custom artifact?

[alenaksu]

Yeah that's a valid point, adding such new property might end up making things even more complex.

In regards to the hidden audit, yes, that's what I tried when I found out that gatherers are filtered.

At first, I didn't get why it was not working, then I realised I needed to include the gatherer in an audit. So I implemented a fake audit, like the one in the example below, but I felt like it was not the best way to do it and I was wondering whether could be feasible to, in a way, decouple gatherers from audits.

class MyAudit extends Audit {
    static get meta() {
        return {
            id: 'my-audit',
            title: 'My Audit',
            failureTitle: 'Dummy failure title',
            description: 'Dummy description',
            requiredArtifacts: ['MyGatherer'],
        };
    }

    static audit() {
        return {
            score: 1
        };
    }
}

Thanks for your feedback, happy to discuss this further but feel free to close the issue.