Improve Live progressive responsiveness

Add transactional progressive publication, durable cancellation, responsive accept cleanup, and framework-safe Svelte and Nuxt previews.\n\nAI-assisted: OpenAI Codex.

skill/scripts/live/session-store.mjs

@@ -3,6 +3,13 @@ import path from 'node:path';
 import { getLegacyLiveSessionsDir, getLiveSessionsDir } from '../lib/impeccable-paths.mjs';
 
 const COMPLETED_PHASES = new Set(['completed', 'discarded']);
+const GENERATION_FENCED_PHASES = new Set([
+  'accept_requested',
+  'discard_requested',
+  'carbonize_required',
+  'completed',
+  'discarded',
+]);
 
 export function createLiveSessionStore({ cwd = process.cwd(), sessionId } = {}) {
   const rootDir = getLiveSessionsDir(cwd);
@@ -38,7 +45,10 @@ export function createLiveSessionStore({ cwd = process.cwd(), sessionId } = {})
       if (!fs.existsSync(journalPath) && fs.existsSync(legacyJournalPath)) {
         fs.copyFileSync(legacyJournalPath, journalPath);
       }
-      const prior = loadCachedOrRebuild(normalized.id);
+      // Publisher/complete helpers can append from a separate process while
+      // the server is alive. Rebuild here so sequence numbers and phase
+      // fences never come from a stale in-memory cache.
+      const prior = rebuildSnapshotFromJournal(getReadableJournalPath(normalized.id), normalized.id);
       const seq = prior.nextSeq;
       const entry = {
         seq,
@@ -119,6 +129,14 @@ function baseSnapshot(id) {
     activeOwner: null,
     sourceMarkers: {},
     fallbackMode: null,
+    generationPhase: null,
+    generationTimings: {},
+    generationEpoch: 1,
+    publishedRevision: 0,
+    deliveredVariants: {},
+    generationCanceled: false,
+    generationCanceledAt: null,
+    cancelReason: null,
     annotationArtifacts: [],
     diagnostics: [],
     updatedAt: null,
@@ -158,6 +176,8 @@ function applyEvent(snapshot, entry, inheritedDiagnostics = []) {
     ...snapshot,
     paramValues: { ...(snapshot.paramValues || {}) },
     sourceMarkers: { ...(snapshot.sourceMarkers || {}) },
+    generationTimings: { ...(snapshot.generationTimings || {}) },
+    deliveredVariants: { ...(snapshot.deliveredVariants || {}) },
     annotationArtifacts: [...(snapshot.annotationArtifacts || [])],
     diagnostics: [...(snapshot.diagnostics || [])],
     updatedAt: entry.ts || new Date().toISOString(),
@@ -170,14 +190,66 @@ function applyEvent(snapshot, entry, inheritedDiagnostics = []) {
   switch (event.type) {
     case 'generate':
       next.phase = 'generate_requested';
+      next.generationEpoch = Number(event.generationEpoch || next.generationEpoch || 1);
       next.pageUrl = event.pageUrl ?? next.pageUrl;
       next.expectedVariants = event.count ?? next.expectedVariants;
       next.pendingEventSeq = entry.seq ?? next.pendingEventSeq;
       next.pendingEvent = toPendingEvent(event);
       if (event.screenshotPath) upsertArtifact(next.annotationArtifacts, { type: 'screenshot', path: event.screenshotPath });
       break;
+    case 'variant_published':
+      if (next.generationCanceled || GENERATION_FENCED_PHASES.has(next.phase)) {
+        next.diagnostics.push({
+          error: 'late_generation_event_ignored',
+          type: event.type,
+          phase: next.phase,
+          revision: event.revision ?? null,
+        });
+        break;
+      }
+      if (Number(event.generationEpoch || 0) !== Number(next.generationEpoch || 1)) {
+        next.diagnostics.push({
+          error: 'stale_generation_epoch_ignored',
+          epoch: event.generationEpoch ?? null,
+          expectedEpoch: next.generationEpoch || 1,
+        });
+        break;
+      }
+      next.phase = 'variants_progress';
+      next.publishedRevision = Math.max(next.publishedRevision || 0, Number(event.revision || 0));
+      next.arrivedVariants = Math.max(next.arrivedVariants || 0, Number(event.arrivedVariants || 0));
+      next.expectedVariants = Number(event.expectedVariants || next.expectedVariants || 0);
+      next.sourceFile = event.sourceFile ?? next.sourceFile;
+      next.previewFile = event.previewFile ?? next.previewFile;
+      next.previewMode = event.previewMode ?? next.previewMode;
+      if (event.revision) {
+        next.deliveredVariants[String(event.revision)] = {
+          digest: event.digest || null,
+          arrivedVariants: Number(event.arrivedVariants || 0),
+          publishedAt: event.at || null,
+        };
+      }
+      break;
+    case 'agent_phase':
+      next.generationPhase = event.phase ?? next.generationPhase;
+      if (event.phase) {
+        next.generationTimings[event.phase] = {
+          at: event.at ?? (Date.parse(entry.ts || '') || null),
+          durationMs: event.durationMs ?? null,
+        };
+      }
+      break;
     case 'variants_ready':
     case 'agent_done':
+      if ((next.generationCanceled || GENERATION_FENCED_PHASES.has(next.phase))
+          && !(event.type === 'agent_done' && event.carbonize === true && next.phase === 'accept_requested')) {
+        next.diagnostics.push({
+          error: 'late_generation_event_ignored',
+          type: event.type,
+          phase: next.phase,
+        });
+        break;
+      }
       next.phase = event.carbonize === true ? 'carbonize_required' : 'variants_ready';
       next.sourceFile = event.sourceFile ?? event.file ?? next.sourceFile;
       next.previewFile = event.previewFile ?? next.previewFile;
@@ -194,7 +266,7 @@ function applyEvent(snapshot, entry, inheritedDiagnostics = []) {
       }
       break;
     case 'checkpoint':
-      if (COMPLETED_PHASES.has(next.phase)) {
+      if (next.generationCanceled || GENERATION_FENCED_PHASES.has(next.phase)) {
         next.diagnostics.push({ error: 'checkpoint_after_terminal_ignored', phase: event.phase ?? null, revision: event.revision ?? null });
         break;
       }
@@ -215,6 +287,9 @@ function applyEvent(snapshot, entry, inheritedDiagnostics = []) {
     case 'accept':
     case 'accept_intent':
       next.phase = 'accept_requested';
+      next.generationCanceled = true;
+      next.generationCanceledAt = event.at ?? (Date.parse(entry.ts || '') || Date.now());
+      next.cancelReason = 'accept';
       next.visibleVariant = Number(event.variantId ?? next.visibleVariant);
       if (event.paramValues) next.paramValues = { ...event.paramValues };
       next.pendingEventSeq = entry.seq ?? next.pendingEventSeq;
@@ -243,6 +318,9 @@ function applyEvent(snapshot, entry, inheritedDiagnostics = []) {
       break;
     case 'discard':
       next.phase = 'discard_requested';
+      next.generationCanceled = true;
+      next.generationCanceledAt = event.at ?? (Date.parse(entry.ts || '') || Date.now());
+      next.cancelReason = 'discard';
       next.pendingEventSeq = entry.seq ?? next.pendingEventSeq;
       next.pendingEvent = toPendingEvent(event);
       break;
@@ -260,6 +338,10 @@ function applyEvent(snapshot, entry, inheritedDiagnostics = []) {
       next.pendingEvent = null;
       break;
     case 'agent_error':
+      if (next.generationCanceled && event.sourceEventType === 'generate') {
+        next.diagnostics.push({ error: 'late_generation_event_ignored', type: event.type, phase: next.phase });
+        break;
+      }
       next.phase = 'agent_error';
       next.pendingEventSeq = null;
       next.pendingEvent = null;