[ixuz]

What and why

Solid Memo wrote up to seven type index registrations per instance: its own sm:Instance one, plus one for each class of the instance's data (dcat:Catalog, sm:Deck, sm:Card, sm:ReviewState, sm:Answer, and sm:Deck again for the drafts). The issue points out that Solid apps register the library a user owns and reach what's inside through their own links. The type index proposal also asks for coarse library types, not every class an app writes. Nothing read the extra registrations, Solid Memo included, and users were left to clean them up by hand.

Only the instance is registered

• Creating an instance, and moving a guest's study into the pod, write only the sm:Instance registration.
• The format update no longer writes anything outside the instance. Until now it added registrations back after every update, including ones the user had removed.
• "Findable by other apps / Register what is missing" is gone from Preferences, along with its strings.

Existing pods

• Removing, deleting and renaming an instance still recognize the registrations earlier versions wrote. Those are removed with the instance, and renaming retitles them.
• Preferences has a new "Old registrations" section. It lists the old entries still there for the open instance and removes them when the user asks.
  • It shows nothing when there are none, and isn't offered to a guest.
  • An entry is removed only when its class, its exact target in the instance and the #sm-…- id the app gave it in that index document all match.
  • The instance's own registration and other apps' entries are left as they are. A registration that also names something else keeps it.
  • It never runs on its own, neither when an instance is opened nor during a format update.

Contract

• This is a breaking change, released as a major version. Other apps can no longer find an instance's catalog, decks, cards, review states, answers or drafts by their class in the type index; they find the instance by sm:Instance and its data from there.
• api/pod-layout.txt now lists only the sm:Instance registration. The first commit says it breaks (! and a BREAKING CHANGE: footer), and check:breaking accepts it.

Checks

• npm run check, lint:reuse and lint:commits pass.
• The pod integration tests cover three cases:
  • a new instance gets one registration;
  • a format update leaves the type index byte for byte unchanged;
  • old entries, another app's entry and an unprefixed lookalike are seeded, and only ours are removed.

Closes: #644