LocalStorage boundary audit: native writer values and peer publication#

This self-review challenged the intersection of the LocalStorage guide's two promises: an active same-tab Collection receives a peer's successful write at the persistence receipt, and a default-JSON writer retains its authored JavaScript value until that Collection restores. The primary executable owner is packages/db/tests/local-storage-peer-oracle.test.ts; the mutation-order owner remains local-storage-order-oracle.test.ts.

Confirmed defect and repair#

An active Collection authored a row containing Date. A same-tab peer then inserted a disjoint row. The first Collection received that new row, but its own Date became an ISO string without restoring. The previous Date witness stopped at the first writer receipt; the peer histories used JSON-native values. Neither crossed these two legal operations.

The peer oracle now compares the writer, peer, durable bytes, and fresh restore at the second write's receipt. It also edits the Date row through the peer to prove that a real same-key change still reaches the original writer. On 256fbd0d9b258ee60ec489c1d171c8b89abb4f16, the new disjoint-write witness failed at the writer's public Date observation: it saw the ISO string. After the repair, it passes. The repair keeps a same-token default-JSON row in its authored representation when its serialized content is unchanged; it still publishes changed content and every new-version row. Custom-parser comparisons retain their previous behavior.

The violated law is bounded here to an active default-JSON writer, two Collections sharing one Storage object and key, an authored Date field, a disjoint successful peer write, and the second persistence receipt. The same-key control and existing parser-normalization histories reject the plausible overcorrection of ignoring all peer content changes. Other native values, arbitrary toJSON side effects, many-operation histories, native browser scheduling, distinct Storage wrappers, and simultaneous cross-tab read-modify-write races are not established by this controlled host.

Negative control#

A separate peer-oracle witness installs a writer subscriber that throws only after Storage contains the accepted row. The callback ran, and the persistence receipt still fulfilled. The writer, peer, durable bytes, and fresh restore contained the row. This experiment did not reveal a product defect; it checks that application observation cannot revoke an accepted Storage write.

Verification and code weight#

The focused LocalStorage owners and examples passed 141 tests with no type errors. The full database runtime suite passed 235 files and 11,393 tests. Standalone source and test TypeScript checks, changed-file lint, package build, and formatting passed. The production repair adds eight lines and removes one; the oracle and contract record are counted separately.