[danReynolds]

Follow-ups to #41 from its review and the comparison with #43, keeping views read-only. There is one commit per change so any of them can be dropped; each passes flutter analyze and the core suite on its own.

1. Dispose only the observers stream builders create (2bae11c). observe() on an observed document or query returns the same observer. A builder given one disposed the caller's observer when the builder was removed, closing it for every other listener, so a second builder sharing it silently stopped updating. Builders now dispose only observers they created. Disposing on a source switch had the same problem and predates Add live read-only subtype collection views #41; that is fixed too. test/core/stream_builder_test.dart covers both, and its caller-owned cases fail on Add live read-only subtype collection views #41.

2. Construct collection views only through view() (6d007f8). CollectionView<String>(animals) compiled and silently matched nothing. The constructor is now private, so view<S>(), which bounds S at compile time, is the only way to create a view.

3. Compare collection views by collection and subtype (0fb3f70). Views compared by identity, so a view created inline in build made QueryStreamBuilder observe and rescan the collection on every rebuild. Views of the same type over the same collection now compare equal, as collections compare by path and document views by path and type.

4. Give views their own stream builders (a033225). Add live read-only subtype collection views #41 changed the DocumentStreamBuilder and QueryStreamBuilder callbacks to read-only snapshots for every caller, so existing builders could no longer write through snap.doc, and Queryable.toQuery() changed type. Those builders keep their signatures from main. DocumentViewStreamBuilder and QueryViewStreamBuilder build from views, and also accept ordinary documents and queries through the read interfaces they implement. With this, the view layer only adds API: the example app is back to its main version, and 6.0.0 code that edits through snap.doc in a builder compiles unchanged. This is the one design change here; drop the commit to keep the unified builders.

5. Sort a view's projected snapshots instead of projecting in the comparator (2440e9d). The view keeps its sort and applies it to its projected snapshots, so comparisons no longer look up projections. In interleaved local runs over 2,000 matching documents, get(), reads after a write, and stream emissions were faster in every round, by roughly 2–2.7× at the median. The machine was under heavy load, so the absolute timings are not meaningful.

Validation

CI only runs for pull requests into main, so these ran locally at the branch head:

• 189 core and 90 native tests pass. The collection view and builder suites pass in Chrome (27), as does the web suite (42). Both CI benchmark workload checks pass, and flutter analyze reports no issues for the package or the example.
• Each commit passes flutter analyze and the core suite on its own.
• The review's randomized comparison of views against plain observers of the parent collection, 400 seeds × 40 batches, still finds no divergence after the sorting change.
• The new tests fail without their fixes: the caller-owned observer tests against Add live read-only subtype collection views #41's builders, and the equality and rebuild tests with the equality reverted.

🤖 Generated with Claude Code