[CmdPal] Fast first paint: render deterministic results before slow fallbacks#49194
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[CmdPal] Fast first paint: render deterministic results before slow fallbacks#49194michaeljolley wants to merge 5 commits into
michaeljolley wants to merge 5 commits into
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…allbacks Defer scoring of global/special fallbacks from keystroke time to the render path (GetSearchViewItems) so slow, asynchronously-resolved fallback titles fold into the already-rendered list with fresh scores from the same ranker, instead of a score frozen against a stale title. Deterministic in-proc results (top-level commands + apps) are unchanged and never wait on the async fallback work, so first paint stays fast. Fallbacks remain pinned at the FallbackFloor tier, so the deferred re-score only reorders them among themselves and can never leapfrog deterministic command/app matches. A superseding keystroke atomically replaces the snapshot (sources + query) and the existing per-keystroke cancellation token drops stale async fallback callbacks. Extract ScoreDeferredFallbacks as an internal static helper and add guardrail unit tests covering deterministic-only first paint, late fallback fold-in with a fresh score, no leapfrog, and supersession by snapshot replacement. Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>
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- ClearResults now also resets _globalFallbackQuery so the snapshot pair (_globalFallbackSources + _globalFallbackQuery) is cleared symmetrically. Behavior is unchanged since ScoreDeferredFallbacks short-circuits on a null source list; this just avoids a confusing leftover value. - Rename the superseding-query test to ReScoreUsesLatestSnapshot_StaleStrongMatchNotApplied and document that it exercises the render-path re-score at the helper level, while the true atomic field swap is guaranteed by the lock in UpdateSearchTextCore / GetItems. Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>
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Warning
This PR is one in a series of PRs focused on rearchitecting the search/scoring logic of the
MainListPage. An explanation of the entire search/scoring logic can be found in the first PR of the change (#49189).This PR should not be merged until PR #49195 is merged into it.
Summary
Phase 4 of the CmdPal search overhaul (stacked on dev/mjolley/provider-weighting). Makes search FEEL fast by ensuring first paint renders deterministic in-proc results (top-level commands + installed apps) immediately, and only folds in slow, out-of-proc fallback contributions asynchronously as they resolve, without re-blocking the UI or letting late fallbacks jarringly reorder deterministic results.
Finding
The typing path (MainListPage.UpdateSearchTextCore) was ALREADY async with respect to slow fallback work:
UpdateQuerycalls.CancellationTokenandFallbackUpdateManagerguards its change callback on that token.The one remaining coupling (the concrete win)
Global/special fallbacks were scored EAGERLY at keystroke time with
FilterListWithScores, freezing the integer score against the fallback's stale (not-yet-resolved) title. When the dynamic title resolved asynchronously, the live Title updated but the frozen score did not.Fix: defer global-fallback scoring to the render path (GetSearchViewItems) so slow fallback results fold into the already-rendered list with fresh scores from the SAME ranker. First paint is unchanged (deterministic commands + apps never depend on this). Only within-floor ordering of fallbacks updates; no cross-tier movement.
Threading / cancellation approach
ScoreDeferredFallbackshelper, always reflecting the latest snapshot._onFallbackChanged -> RequestRefresh(false)path, which is guarded by the per-keystroke cancellation token, so stale slow results are dropped.Tests
New
FastFirstPaintTests(6 tests) covering: deterministic-only first paint with no fallback contribution, unresolved fallback absent at first paint, slow fallback folds in when its title resolves, re-score reflects the current title (not a frozen value), superseding query replaces the snapshot (stale strong match not applied), and late fallback merges below deterministic matches (no leapfrog). Uses a fake mutable-title source; no dependency on real extensions.Build & test
*.UnitTestspass (x64 host). ViewModels: 163/163. Only non-green is the known pre-existing WindowWalker 'Zero tests ran'.