fix(desktop): keep bottom pins through virtualizer settle#1328
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Co-authored-by: Tyler Longwell <tlongwell@block.xyz> Signed-off-by: Tyler Longwell <tlongwell@block.xyz>
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…oexists in two communities Conformance matrix row `channels_membership` (re-routed from Mari to Quinn at Eva's call — Mari's #1328 scroll-fix is still landing on main, and the row's substrate is the same same-UUID-in-two-communities shape I already used as the setup for `search_fts`). Fills the `pending_lane("buzz-db", ...)` stub at `crates/buzz-test-client/tests/conformance_multitenant.rs::mod channels_membership`. The row's scope is the **positive arm** of the same `is_member_cached` scope branch that `row_zero_host_binding`'s `#h` override-attempt row exercises as the **negative arm**. Sibling-not-replacement, per the frame Dawn established when cold-reading row_zero (b): row_zero proves the override-attempt fails closed against `get_channel(A, U) == None`; this row proves the coexistence positive — when U exists in *both* A and B (legal under the `(community_id, id)` PK), `get_channel` finds the right per-community row and each community's posts land in its own instance. A bug that resolves `get_channel`/`is_member_cached` against the claimed community instead of the host-derived one would pass row_zero (b)'s negative-arm test (rejection still happens for some reason) but fail this row's positive-arm test (A's post might land in B's channel or be returned to B's query). So this row catches a class of bugs row_zero (b) structurally cannot, even though both share the `is_member_cached` scope branch. Shape: 1. One keypair shared across both communities — proves the fence is `community_id`, not `pubkey`. 2. Same channel UUID `U` created in both A and B via REST kind:9007. 3. Same key posts kind:9 with community-distinct content to U on each WS-AUTH'd connection ("A message in shared-UUID channel" / "B message in shared-UUID channel"). Distinct content per the named setup-equivalence-vacuity lesson in `landed-on-head-discipline` — without it, distinct rows would collide on Nostr event id (hash includes content; community is server-side provenance, not in the hash) and a leak would be indistinguishable from the honest path on the wire. 4. REST `POST /query` with `{kinds:[9], #h:[U]}` against each host. 5. Each side: count == 1, content == own community's. A leak surfaces as count == 2 (both rows returned through shared `#h: U` filter) OR content mismatch on count == 1. Bar (by my own hands against the live `:3100` harness, PR head `6aa0cec4a`): Clean → GREEN. Mutate (single fence — single-fence-per-path topology here, unlike search_fts's defense-in-depth): - crates/buzz-db/src/event.rs:266-270 — `query_events` non-p-tag branch `WHERE community_id = ` → `WHERE TRUE` (using the `let _ = q.community_id;` pattern Eva established on row_zero, one of the three honest sidesteps for the param-count trap I flagged in my prior message; the other two are renumbering and `( IS NOT NULL)`). → RED on `hits_a.len() == 1` with the failure message listing both contents: ["B message in shared-UUID channel", "A message in shared-UUID channel"] Distinct content makes the leak observable as B's message surfacing inside A's wire response. Restore → diff empty → GREEN. Bar checklist: - `cargo fmt -p buzz-test-client -- --check`: exit 0. - `cargo clippy -p buzz-test-client --tests -- -D warnings`: clean. - `cargo test -p buzz-test-client --tests`: full package non-ignored green (4 nip42_host_binding_live tests are #[ignore]'d by design). - Strict-FF onto PR head: this is +1 on `6aa0cec4a`, verified by `git merge-base --is-ancestor` + `git rev-list --count`. - Trailers preserved as single pair via initial `--trailer` flag (not `--amend --trailer`, which doubled them earlier in the session). - Live two-host harness on `:3100`: my clean (post-restore) binary, recipe per RESEARCH/CONFORMANCE_MATRIX_STATUS_2026-06-27.md v3. Conformance lane: this row is one of fourteen in the file; per Eva's row-ownership contract, this commit touches only the `channels_membership` module. No other rows modified. Co-authored-by: Tyler Longwell <tlongwell@block.xyz> Signed-off-by: Tyler Longwell <tlongwell@block.xyz>
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Summary
Fixes the desktop timeline bottom-pin race where programmatic bottom jumps could be reclassified as a message anchor while the virtualizer was still settling row measurements.
Changes:
Validation
cd desktop && pnpm typecheck✅cd desktop && pnpm exec biome check src/features/messages/ui/useAnchoredScroll.ts src/features/messages/ui/useAnchoredScroll.test.mjs✅cd desktop && pnpm test -- src/features/messages/ui/useAnchoredScroll.test.mjs✅ (runs desktop unit suite; 1196 passed including new tests)pnpm exec playwright test --project=integration stream.spec.ts -g "stays pinned after you send a message|keeps scroll position when new messages arrive above the fold" --repeat-each=5 --retries=0 --reporter=list✅ 10/10Mutate → red → restore
Mutated
settleProgrammaticBottomPinback to the old behavior: no floor-chasingscrollTo, and clear based on looseisAtBottomNowinstead of strict physical-bottom check.Result: the new deterministic unit tests went red:
settleProgrammaticBottomPin chases the physical floor before clearingfailed because no scroll write happened.settleProgrammaticBottomPin keeps settling when the floor is still out of reachfailed because the loose threshold returned true with a 2px physical gap.Restored the helper and re-ran typecheck/biome/unit suite green.