☂️ 👣 Breaking changes for v5

[paulirish]

A la #6202 and #4333, the items we are thinking of changing in the next major rls

• Kill rawValue Remove rawValue from Audit.Result #6199 (PRs core: require score in audit product; make rawValue numeric only #8343, core: replace rawValue with numericValue in audit result #8385, core: replace remaining rawValue with numericValue #8421)
• Remove disableDeviceEmulation flag before v5 Remove disableDeviceEmulation flag before v5 #7044 (PR core: remove disableDeviceEmulation flag #8289)
• (minor) Inconsistent format of screenshot-thumbnails and final-screenshot (minor) Inconsistent format of screenshot-thumbnails and final-screenshot #7092 (PR core(screenshots): match format of final-screenshot #8299)
• Switch to a different name for LH.Audit.Details.Diagnostic. "Diagnostic" is too overloaded in LH. (PR core: rename diagnostics to debugData #8298)
• Move to minimum Node 10 Move to Node 10 #7215 (PR misc: drop support for Node before 10.13 (LTS) #8117)
• Lantern FCP improvements (PR core(lantern): FCP improvements #7513)
• Collect only elements in body for dom-size (PR core(dom-size): collect only body nodes for DOM stats #7241)
• New a11y audit weights? (PR core(a11y): update scoring weights based on severity #8823)
• Turn on advanced LR network timings (PR clients(lr): apply Lightrider timings to NetworkRequests #8109)
  • Reverted in PR clients(lr): revert Lightrider timings applied to NetworkRequests #8752

Maybe:

Punted: 🏈

• benchmarkIndex => CPU throttling core(throttling): add option to slowdown to a device class #6162
• Consider always filtering configs Consider always filtering configs to allow extra gatherers that won't run by default #7787

No:

• Expose page functions to custom gatherers Expose page functions to custom gatherers #7317
• drop null from SharedFlagsSettings properties drop null from SharedFlagsSettings properties #7788

Please add any additional above.

[brendankenny]

one bullet point might be to decide on our v5 public interface, at least the start of one. This could also involve finally publishing the our public types :)

I bring this up because

Expose page functions to custom gatherers #7317

Right now we're reluctant to call even artifacts a public interface since it will make some (even minor) changes a lot harder. We should be judicious in what we expose because we can't tweak or take them back later.

Page functions are short enough (and usually self contained enough) that they could be a good candidate for a list of "useful functions you might want to copy/paste" if we didn't want to commit to their current form, for instance.

[benschwarz]

Thanks for posting. We'll be tracking against this.

[exterkamp]

Are we going to touch rawValues at all for v5?

[patrickhulce]

oh yeah let's make the .details.timeInMs or whatever a thing :)

[exterkamp]

benchmarkIndex => CPU throttling #6162

This is out, right?

[patrickhulce]

@exterkamp ya, I'll go ahead and close the PR actually.

[brendankenny]

These are complete! Any further breaking changes we come across we should add to #8331.

If you retroactively realize we already added a breaking change, please also add those to #8331 so they will be easier to document in the 5.0 changelog.