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Documentation / @etherfold/processor-entities / StateStoreCapabilities

Type Alias: StateStoreCapabilities ​

StateStoreCapabilities = object

Defined in: packages/state-store/dist/capabilities.d.ts:61

What a store declares about itself, available before migrate and before any read.

Properties ​

asOf ​

readonly asOf: boolean

Defined in: packages/state-store/dist/capabilities.d.ts:71

Whether the store answers as-of reads AT ALL.

Separate from retention because they fail differently: a store with a window answers inside it and refuses outside it, while a store that cannot reconstruct history refuses everywhere. A revert-only store therefore reports asOf: false, and a caller that needs history knows at startup.

retention ​

readonly retention: Retention

Defined in: packages/state-store/dist/capabilities.d.ts:62

singleWriter ​

readonly singleWriter: boolean

Defined in: packages/state-store/dist/capabilities.d.ts:99

Whether a SECOND writer on this store's storage is refused rather than allowed to corrupt it.

true means every mutating path carries a writer token checked in the same atomic unit as the write it guards, so a writer whose claim has been taken over is refused with StoreWriterChangedError and writes nothing (writer.ts, ADR-0075).

It is REPORTED rather than assumed because not every backend can hold a meaningful guard, and pretending otherwise produces a vacuous test. MemoryStateStore and the patch store keep their storage in instance fields, so no second writer can reach it and a token there could only ever be compared with itself: green, tested, and meaningless. They report false honestly, and the conformance suite selects the contention cases on this claim.

It is a fact about one unit of STORAGE and not about a process, a tab or an origin: two stores addressed apart (a second databaseName, a second table namespace) never contend, which is what keeps two generations of one indexer writing at once.

Distinct from the ONE-WRITER RULE on the stream keeper, which says only the indexing generation APPENDS TO A STREAM and is structural (a follower is handed a read-only view, ADR-0044). Same words, different seam: that one decides who may write, this one enforces that whoever does is alone.