fix(explorer): dedupe temporal snapshot requests and apply latest-wins
The temporal snapshot effect fetched /api/temporal/snapshot with no
idempotency or ordering guards. Upstream churn (timeline recreation
while bounds settle, play ticks resetting the playhead, drag events)
could re-request the same `at` repeatedly, and with variable network
latency an older position's response could land after a newer one's,
overwriting the active-node count, so the chip visibly lagged the
scrubber.
Add a small stateful guard module (temporalSnapshotGuards.ts) built
around a per-position cache, keyed by the debounced timestamp's
primitive millisecond value rather than the Date object, so upstream
object-identity churn cannot defeat the dedup on its own:
- at most one in-flight request per scrubber position, so identical
`at` values arriving while a request is pending are dropped instead
of firing a fresh fetch, breaking the idle/play polling loop;
- successful snapshots are cached per position and re-applied when the
scrubber returns to it (play wrap-around, back-scrubbing) without a
network round trip;
- a response is applied only while the scrubber is still on the
position it was requested for, so an out-of-order response can never
clobber a newer position's count;
- failed, cancelled, or superseded requests release their position so
it can be fetched again the next time it's visited, rather than
stalling it permanently;
- reset() drops all cached and in-flight state when the underlying
graph summary changes (reload/retry), since snapshots cached against
the previous graph no longer describe anything real. Keyed on the
summary query's data identity, which react-query keeps stable
(staleTime: Infinity plus structural sharing) unless the graph data
itself was replaced, so reset fires exactly on a real reload and not
on cosmetic re-renders.
The snapshot effect is wired through the guards end to end: begin()
returns either a fresh sequence number to fetch under or a cached
snapshot to reapply directly; the same shouldApply()/apply() gate
handles both the network and cached-reapply paths so they can't drift
apart; finish() runs from both the fetch's failure branch and its
cleanup function, so a cancelled or failed request is always retryable
on the next visit instead of leaving its position stuck in-flight.
16 unit tests cover dedup, independent positions, revisit re-apply,
play wrap-around, failure retry, stale-sequence protection (a late
response or a late release from a superseded request cannot act on a
newer request's position), reset-on-reload, and cache-bound eviction.
Closes#1128
MarkdownContentViewer.tsx exported the isSafeUrl helper alongside the
component so it could be unit tested, which tripped
react-refresh/only-export-components.
Move the helper into a sibling pure module, markdownUrlSafety.ts,
following the existing GraphWorkspace convention for testable non-component
logic (graphAnalytics.ts, pluginRegistryPredicates.ts,
temporalLifecyclePredicates.ts). The function body is moved verbatim — the
scheme allowlist, protocol-relative rejection, whitespace-only guard and
malformed-URL handling are unchanged — so the existing URL-safety tests pass
untouched apart from the import path.
The component module now exports only its component and prop type, clearing
the lint error without any change to the lint configuration.
Co-authored-by: Pravit Ampapathini <pravit.amp@gmail.com>
Explorer was firing temporal requests before the graph even loaded.
When the backend is down, /api/graph/nodes fails but the temporal
bounds and snapshot effects didn't care , they fired anyway, off in
their own corner, ignoring whether the graph actually came up. Every
page load with no backend meant three failed requests instead of one,
and a scrubber that had nothing to scrub.
Added two small predicate functions and gated the temporal effects on
them. Basically: don't ask for time-based data until you know the
graph itself loaded. An empty graph still counts as loaded, so that
case isn't broken.
Confirmed with the backend down, before and after: three failing
requests down to one.
Fixes#982.
- pluginRegistryPredicates.ts: consolidate 8-line JSDoc to 5 lines,
removing redundant detail that restated implementation mechanics
already obvious from the code.
- GraphWorkspace.tsx: shorten the lastScrubberMsRef comment from 5 lines
to 2; trim the handleDiagnosticsChange block comment by removing the
'rather than bailing out' implementation-alternative sentence; tighten
the distanceVisual inline comment.
- pluginRegistry.temporal.test.mjs: replace 17-line file-level JSDoc
with 9 lines focused on the invariant rather than the root-cause
narrative (already covered in pluginRegistryPredicates.ts); remove
two tsx loader implementation-detail comments; tighten two test-level
inline comments.
No logic, types, or test assertions changed. All 42 tests pass.
Two issues addressed:
1. Plugin-loading useEffect unnecessarily depended on temporalState.
After the #830 fix, no shouldLoad predicate reads temporalState, but
the effect's dep array still included it, causing extra re-runs on
every scrubber update. Removed temporalState from the dep array and
the shouldLoad call site. Made temporalState optional in the
LazyPluginRegistryEntry shouldLoad context type to match.
2. Regression test imported a local copy of shouldLoad instead of the
production predicate. Extracted all three shouldLoad predicates into
pluginRegistryPredicates.ts (pure module, no React/DOM dependencies),
wired GraphWorkspace.tsx to use the imported functions, and updated
the test to import and exercise the real production code via tsx.
Verified: introducing the old broken condition causes the test to fail;
the correct implementation passes all 7 assertions.
temporalDiffState.ts belongs to feat/793-temporal-diff-ui and should not
appear in the #830 diff. Remove it from this branch's tracked files.
Add the pluginRegistry.temporal.test.mjs regression test that covers the
shouldLoad fix committed in the main #830 commit (it was never committed).
Add test:plugin-registry script to package.json so the regression test
can be run via npm run test:plugin-registry.
- Fix `import.meta.env.DEV` crash in graphSceneState.ts that broke the
entire test:graph-workspace suite (module load fails in Node.js/tsx)
- Export `resolveGroupedDisplayNodeId` from graphSceneState.ts and
remove the identical copy in GraphWorkspace.tsx
- Add `checkGroupedViewAvailability` helper (Louvain only, no centrality)
so grouped view availability can be checked cheaply on every graph change
- Gate full community graph build (`groupedDisplayCandidate`) on
`viewMode === 'grouped'` to avoid running Louvain + centrality on every
graph version tick when the user is not in grouped view
- Remove dead ternary in `focusNode` where both branches returned `nodeId`
- Add 7 new tests covering resolveGroupedDisplayNodeId,
resolveGroupedDisplayStateSnapshot, and checkGroupedViewAvailability
Co-Authored-By: ZohaibHassan16 <109234410+ZohaibHassan16@users.noreply.github.com>
Co-Authored-By: KaifAhmad1 <mohammadk78600@gmail.com>
Aldrin Joseph