RFC: Remove `subpath` URLQueryParam from settings pages.

[tomalec]

(This is a follow-up from https://github.com/woocommerce/google-listings-and-ads/pull/1025#discussion_r717420234)

Changes proposed in this Pull Request:

Remove subpath URLQueryParam from settings pages. Use WC navigation features instead.

This way we have

• routing unified with the WC stack
• less noise in URLs & track events
• more intuitive URL & track event props, as the entire path is in a single param, not divided into a number of chunks
• could get closer to simplify .~/utils/url.js, as we no longer need to construct a query object, but just use path param.
• remove the source of problems like the one discussed at https://github.com/woocommerce/google-listings-and-ads/pull/1025#discussion_r717420234, TL;DR: "what if subpath is empty?"

What's left/missing/to be done later:

• [ ] Update track event README
• [ ] Try to simplify wc_admin_register_page calls in src/Menu/Settings.php
• [ ] :scroll: extrapolate for all other pages using subpath or similar param.
• (edit) ~[ ] 📜(not sure if possible in WC-plaform) DRY/reduce duplication, of pages configs in src/Menu/*.phps, js/src/index.js and js/src/utils/url.js~ -> https://github.com/woocommerce/google-listings-and-ads/issues/1037

Screenshots:

Detailed test instructions:

1. Go to Settings page /wp-admin/admin.php?page=wc-admin&path=%2Fgoogle%2Fsettings
2. Navigate into phone & address pages - "Edit" buttons
3. Navigate away and around observing how URL changes, and what track events are fired. (full page reloads instead of SPA-morph, is an unrelated issue https://github.com/woocommerce/google-listings-and-ads/issues/1027)

Changelog entry

Make all settings pages use only path for navigation.

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//cc @eason9487 @ecgan

[ecgan]

@tomalec , the reason why we use subpath is to make the pages work with the new WC Navigation beta feature. Refer to the following links:

• https://github.com/woocommerce/google-listings-and-ads/pull/605#issuecomment-847288673
• https://github.com/woocommerce/google-listings-and-ads/issues/665
• https://github.com/woocommerce/google-listings-and-ads/pull/743 (This has video demo.)

You can enable the WC Navigation feature in WC Settings > Advanced > Features.

[tomalec]

I managed to achieve that by using matchExpression property

It was quite hidden in the docs, so I found it by debugging it live :man_facepalming: But I hope it's stable enough and desired usage.

[tomalec]

Highlighting the subpages in legacy menu is covered by https://github.com/woocommerce/google-listings-and-ads/pull/1038

[findingsimple]

Mental note - before we go merging will this impact any funnels we have set up or direct links we may have (in the codebase or docs)

[tomalec]

will this impact any funnels we have set up or direct links we may have (in the codebase or docs)

Yes, it will. All path=/google/settings&subpath={subpath} will become path=/google/settings/{subpath}.

So the url, path and subpath event props will change respectively.

That's why I still have on my todo list:

Update track event README

[tomalec]

@jconroy does the above make it a no-go? or maybe it's ok, but we should change everything at once, to update the docs and funnels only once, to minimize the inconvenience, for users of those.

[eason9487]

Thanks for proposing the RFC, @tomalec! After several years of iteration, the new WooCommerce Navigation has been deprecated (see #2406). The stale PRs related to it will likely require reassessment for appropriate solutions, so I am closing this PR.