Stabilize transcript scrolling and Markdown surfaces / 稳定 transcript 滚动与 Markdown 展示

desktop/frontend/package.json

@@ -26,7 +26,7 @@
     "test:motion-browser": "PLAYWRIGHT_BROWSERS_PATH=.pw-browsers node bench/approval-animation.mjs",
     "test:theme-browser": "PLAYWRIGHT_BROWSERS_PATH=.pw-browsers node bench/theme-surface-contract.mjs",
     "test:diagnostics": "tsx src/__tests__/diagnostics-settings.test.tsx",
-    "test:transcript": "tsx src/__tests__/transcript-geometry-replay.test.ts && tsx src/__tests__/transcript-virtuoso-index.test.ts && tsx src/__tests__/transcript-row-geometry.test.ts && tsx src/__tests__/transcript-live-turn-stability.test.tsx && tsx src/__tests__/transcript-geometry-environment.test.ts && tsx src/__tests__/transcript-measured-sizes.test.ts && tsx src/__tests__/transcript-state-snapshot.test.ts && tsx src/__tests__/transcript-layout-recovery.test.ts && tsx src/__tests__/transcript-reader-extent-stability.test.ts && tsx src/__tests__/transcript-reader-extent-race.test.tsx && tsx src/__tests__/transcript-recovery-race.test.tsx && tsx src/__tests__/transcript-same-tab-tail-race.test.tsx && tsx src/__tests__/transcript-history-prepend-race.test.tsx && tsx src/__tests__/transcript-anchor-compensation-race.test.tsx && tsx src/__tests__/transcript-scroll-release.test.ts && tsx src/__tests__/transcript-tail-clamp-race.test.ts && tsx src/__tests__/transcript-scroll-writer.test.ts && tsx src/__tests__/transcript-scroll-diagnostics.test.ts && tsx src/__tests__/frontend-diagnostics.test.ts && tsx src/__tests__/project-tree-diagnostics.test.ts && tsx src/__tests__/transcript-native-scrollbar.test.ts && tsx src/__tests__/nested-scroll-handoff.test.ts && tsx src/__tests__/reasoning-scroll-follow.test.tsx && tsx src/__tests__/creation-transcript-scrollbar.test.ts && tsx src/__tests__/question-jump-bar.test.tsx && tsx src/__tests__/transcript-question-nav.test.ts && tsx src/__tests__/transcript-question-nav-integration.test.ts && tsx src/__tests__/markdown-table-virtual.test.tsx && tsx src/__tests__/typography-overflow-contract.test.ts && tsx src/__tests__/transcript-selection-retention.test.tsx && tsx src/__tests__/transcript-logical-selection.test.ts && tsx src/__tests__/transcript-selection-overlay.test.tsx && tsx src/__tests__/markdown-pipeline.test.tsx && tsx src/__tests__/message-selection-copy.test.ts && tsx src/__tests__/transcript-selection-menu.test.tsx && tsx src/__tests__/transcript-selection-rendering.test.ts && tsx src/__tests__/transcript-store.test.ts && tsx src/__tests__/transcript-virtualization.test.tsx && tsx src/__tests__/transcript-question-jump.test.tsx",
+    "test:transcript": "tsx src/__tests__/transcript-geometry-replay.test.ts && tsx src/__tests__/transcript-virtuoso-index.test.ts && tsx src/__tests__/transcript-row-geometry.test.ts && tsx src/__tests__/transcript-live-turn-stability.test.tsx && tsx src/__tests__/transcript-geometry-environment.test.ts && tsx src/__tests__/transcript-measured-sizes.test.ts && tsx src/__tests__/transcript-state-snapshot.test.ts && tsx src/__tests__/transcript-layout-recovery.test.ts && tsx src/__tests__/transcript-reader-extent-stability.test.ts && tsx src/__tests__/transcript-reader-extent-race.test.tsx && tsx src/__tests__/transcript-recovery-race.test.tsx && tsx src/__tests__/transcript-same-tab-tail-race.test.tsx && tsx src/__tests__/transcript-history-prepend-race.test.tsx && tsx src/__tests__/transcript-anchor-compensation-race.test.tsx && tsx src/__tests__/transcript-scroll-release.test.ts && tsx src/__tests__/transcript-tail-clamp-race.test.ts && tsx src/__tests__/transcript-scroll-writer.test.ts && tsx src/__tests__/transcript-scroll-diagnostics.test.ts && tsx src/__tests__/frontend-diagnostics.test.ts && tsx src/__tests__/transcript-surface-transaction.test.ts && tsx src/__tests__/project-tree-diagnostics.test.ts && tsx src/__tests__/transcript-native-scrollbar.test.ts && tsx src/__tests__/nested-scroll-handoff.test.ts && tsx src/__tests__/reasoning-scroll-follow.test.tsx && tsx src/__tests__/creation-transcript-scrollbar.test.ts && tsx src/__tests__/question-jump-bar.test.tsx && tsx src/__tests__/transcript-question-nav.test.ts && tsx src/__tests__/transcript-question-nav-integration.test.ts && tsx src/__tests__/markdown-table-virtual.test.tsx && tsx src/__tests__/typography-overflow-contract.test.ts && tsx src/__tests__/transcript-selection-retention.test.tsx && tsx src/__tests__/transcript-logical-selection.test.ts && tsx src/__tests__/transcript-selection-overlay.test.tsx && tsx src/__tests__/markdown-pipeline.test.tsx && tsx src/__tests__/message-selection-copy.test.ts && tsx src/__tests__/transcript-selection-menu.test.tsx && tsx src/__tests__/transcript-selection-rendering.test.ts && tsx src/__tests__/transcript-store.test.ts && tsx src/__tests__/transcript-virtualization.test.tsx && tsx src/__tests__/transcript-question-jump.test.tsx",
     "test:transcript-browser": "node bench/transcript-selection.mjs && node bench/transcript-scroll-stability.mjs && node bench/composer-transcript-stability.mjs",
     "test:transcript-reader-browser": "node bench/transcript-reader-transaction.mjs",
     "pretest": "pnpm test:terminal && pnpm test:task-monitor && pnpm test:composer && tsx src/__tests__/context-center-contract.test.ts && tsx src/__tests__/provider-model-cache.test.ts && tsx src/__tests__/format-tokens.test.ts && pnpm test:usage-stats && pnpm test:settings-responsive && pnpm test:composer-menu-viewport && pnpm test:diagnostics && pnpm test:transcript",

desktop/frontend/scripts/check-bundle-budget.mjs

@@ -180,9 +180,11 @@ console.log("\nbundle budgets");
 // move the combined path to 462.2 KiB. Local spectator reclaim adds the
 // desktop-vs-remote command branch. Sticky Context's session-scoped file chips
 // bring the merged stable path to 462.587 KiB. Windows' embedded build metadata
-// lands just above the rounded 462.6 KiB boundary; retain one cross-platform
-// decimal step without widening any chunk or raw gate.
-const initialJSBudgetKiB = 462.7;
+// lands just above the rounded 462.6 KiB boundary. The generation-bound
+// surface transaction and content-free reversal diagnostics add 0.7 KiB to
+// the initial path; retain the smallest one-decimal ratchet without widening
+// any chunk or raw gate.
+const initialJSBudgetKiB = 463.7;
 assertBudget("initial JavaScript gzip", initialJSGzip, initialJSBudgetKiB * 1024);
 assertBudget("largest initial JavaScript chunk gzip", largestInitialJS, 280 * 1024);
 // Render-blocking CSS is intentionally absent: styles.css loads deferred via
@@ -324,10 +326,11 @@ const rawInitialBytes = [...initialJS, ...initialCSS, ...appShellCSS]
 // path 2465.105 KiB raw; the merged test channel measures 2464.979 KiB.
 // Session takeover banners and #9703/#9711's provisional-selection handoff
 // combine with Sticky Context's pinned-file state at 2469.125 KiB raw on the
-// merged stable path. Retain only the next one-decimal ceiling.
-// The passive reader-anchor lease for delayed WebView2 range commits measures
-// 2469.347 KiB raw (+0.222 KiB, +0.009%). Retain only the next one-decimal
-// ceiling; gzip and largest-chunk budgets remain unchanged.
-const rawInitialBudgetKiB = 2_469.4;
+// merged stable path. The bounded surface transaction, scrollbar rebase, and
+// Markdown empty-block guard add 3.1 KiB raw; the native-thumb generation
+// fence adds the final measured 0.3 KiB. Retain the smallest one-decimal
+// ceiling for the measured 2473.1 KiB path after adding the reader-lease
+// writer fence on top of the latest main-v2 anchor-compensation baseline.
+const rawInitialBudgetKiB = 2_473.5;
 assertBudget("initial raw JavaScript and CSS", rawInitialBytes, rawInitialBudgetKiB * 1024);
 assertBudget("largest initial JavaScript chunk raw", largestInitialJSRaw, 1_000 * 1024);

desktop/frontend/src/__tests__/creation-transcript-scrollbar.test.ts

@@ -2,6 +2,7 @@
 
 import {
   mapFrozenScrollbarDrag,
+  rebaseFrozenScrollbarDrag,
   readCreationScrollbarGeometry,
 } from "../lib/useCreationTranscriptScrollbar";
 
@@ -36,12 +37,16 @@ const moved = mapFrozenScrollbarDrag(drag, 200);
 eq(moved.thumbTop, 420, "drag follows pointer pixels on the frozen track");
 eq(moved.scrollTop, 2_100, "drag maps through the frozen pointerdown overflow");
 
-// Content can grow while virtual rows mount. The active drag must keep using
-// the pointerdown geometry rather than changing sensitivity under the pointer.
+// Content can grow while virtual rows mount. Rebase the active drag at the
+// current physical position so the next pointer move cannot write through a
+// stale extent while preserving the thumb's visible position.
 const grown = readCreationScrollbarGeometry(800, 8_000);
 if (!grown) throw new Error("expected grown scrollable geometry");
 eq(grown.overflow, 7_200, "content growth would otherwise change the live mapping");
-eq(mapFrozenScrollbarDrag(drag, 200).scrollTop, 2_100, "content growth cannot remap an active drag");
+const rebased = rebaseFrozenScrollbarDrag(drag, grown, 2_100, 200);
+eq(rebased.startY, 200, "geometry rebase pins the drag to the latest pointer sample");
+eq(rebased.startThumbTop, 210, "geometry rebase preserves the current physical scroll ratio");
+eq(mapFrozenScrollbarDrag(rebased, 300).scrollTop, 3_100, "subsequent drag movement uses the current extent");
 
 eq(mapFrozenScrollbarDrag(drag, -1_000).thumbTop, 0, "drag clamps at the top");
 eq(mapFrozenScrollbarDrag(drag, 2_000).thumbTop, 640, "drag clamps at the bottom");

desktop/frontend/src/__tests__/frontend-diagnostics.test.ts

@@ -154,5 +154,11 @@ assert.deepEqual(analyzeFrontendDiagnosticAnomalies([
   { t: 0, type: "navigation.begin", intent: 9 },
   { t: 1, type: "navigation.settle", intent: 9, outcome: "failed" },
 ]), [], "a failed data terminal may release its mask without a paint-ready false positive");
+assert.deepEqual(analyzeFrontendDiagnosticAnomalies([
+  { t: 0, type: "transcript.scroll-anomaly", transactionId: 40, result: "restore-anchor", reverseDisplacement: 2.01 },
+  { t: 1, type: "transcript.scroll-anomaly", transactionId: 40, result: "restore-anchor", reverseDisplacement: 27_104.41 },
+]), [
+  { code: "unauthorized-scroll-reversal", transactionId: 40, maxReverseDisplacement: 27_104.41 },
+], "large reader reversals are surfaced in the diagnostic summary");
 
 console.log("frontend diagnostics tests passed");

desktop/frontend/src/__tests__/markdown-pipeline.test.tsx

@@ -111,6 +111,21 @@ for (const [name, text] of Object.entries(fixtures)) {
   eq(sliced, expected, `${name}: sliced blocks render identically (${blocks.length} blocks)`);
 }
 
+// Empty fenced blocks are formatting placeholders. They must not create a
+// bordered CodeViewer, while comment-only and whitespace-adjacent blocks stay
+// visible as real code content.
+{
+  const emptyFences = "Before\n\n```\n\n```\n\nAfter\n\n```ts\n   \n```";
+  const html = renderCurrent(emptyFences);
+  ok(!html.includes("code-block"), "empty fenced blocks do not render phantom code cards");
+  ok(html.includes("Before") && html.includes("After"), "text around empty fenced blocks remains visible");
+
+  const comments = "```ts\n// keep this comment\nconst stable = true;\n```";
+  const commentHtml = renderCurrent(comments);
+  ok(commentHtml.includes("keep this comment"), "non-empty comment code blocks remain visible");
+  ok(commentHtml.includes("code-block"), "non-empty comment code keeps its code-block surface");
+}
+
 // Block keys are stable top-level indexes.
 {
   const blocks = parseMarkdownToBlocks("one\n\ntwo\n\nthree");

desktop/frontend/src/__tests__/transcript-diagnostic-replay.fixtures.ts

@@ -11,3 +11,25 @@ export const unloadedQuestionJumpReplay = {
     { firstTurn: 1, lastTurn: 994, hasOlderHistory: false, rowCount: 994 },
   ] as const,
 } as const;
+
+// Anonymous scroll evidence distilled from the Windows field report
+// `reasonix-frontend-diagnostics-8a5de879.json`. Text, paths and stable row IDs
+// are intentionally omitted; only the geometry needed to prevent regression is
+// retained.
+export const field9711ScrollReplay = {
+  buildCommit: "d9cd713",
+  viewport: 555,
+  direction: -1,
+  result: "restore-anchor",
+  transactions: [
+    { id: 40, maxReverse: 2_593.02, extentDelta: 5_185 },
+    { id: 54, maxReverse: 299.68, extentDelta: 589 },
+    { id: 59, maxReverse: 7_252.06, extentDelta: 14_492 },
+    { id: 62, maxReverse: 4_586.03, extentDelta: 9_163 },
+    { id: 64, maxReverse: 5_685.71, extentDelta: 11_371 },
+    { id: 66, maxReverse: 6_836.19, extentDelta: 13_700 },
+    { id: 71, maxReverse: 5_342.22, extentDelta: 10_692 },
+    { id: 75, maxReverse: 5_217.14, extentDelta: 10_497 },
+    { id: 81, maxReverse: 27_104.41, extentDelta: 51_140 },
+  ],
+} as const;

desktop/frontend/src/__tests__/transcript-geometry-replay.test.ts

@@ -5,6 +5,7 @@ import { readFileSync } from "node:fs";
 import { dirname, join } from "node:path";
 import { fileURLToPath } from "node:url";
 import { isSupportedFrontendDiagnosticSchemaVersion } from "../lib/frontendDiagnostics";
+import { field9711ScrollReplay } from "./transcript-diagnostic-replay.fixtures";
 
 type Fixture = {
   schemaVersion: number;
@@ -30,3 +31,8 @@ for (const name of names) {
 }
 
 console.log("transcript anonymous geometry replay fixtures passed");
+
+assert.equal(field9711ScrollReplay.buildCommit, "d9cd713", "field replay is tied to the reported main-v2 build");
+assert.equal(field9711ScrollReplay.transactions.length, 9, "field replay retains every unauthorized reversal transaction");
+assert.equal(Math.max(...field9711ScrollReplay.transactions.map((entry) => entry.maxReverse)), 27_104.41, "field replay retains the largest reported reversal");
+assert.ok(field9711ScrollReplay.transactions.every((entry) => entry.maxReverse > 2 && entry.extentDelta > 0), "field replay keeps only geometry reversals beyond tolerance");

desktop/frontend/src/__tests__/transcript-question-jump.test.tsx

@@ -139,6 +139,10 @@ ok(newestSurface === null, "only C's own terminal releases the latest surface");
         rowTop >= el.scrollTop - 100 && rowTop <= el.scrollTop + el.clientHeight,
         `jump to question ${targetIndex + 1} lands its row inside the viewport (rowTop ${rowTop}, scrollTop ${el.scrollTop})`,
       );
+      if (targetIndex > 0 && targetIndex < 39 && rowTop !== null) {
+        ok(Math.abs(rowTop - el.scrollTop - 16) <= 1,
+          `jump to question ${targetIndex + 1} keeps the selected row near the 16px top margin`);
+      }
       const expectedText = `question ${targetIndex}`;
       ok(anchor.textContent?.includes(expectedText) ?? false, `jump to question ${targetIndex + 1} mounts the selected question content`);
     }

desktop/frontend/src/__tests__/transcript-reader-extent-race.test.tsx

@@ -767,6 +767,35 @@ check(scrollElement.dataset.nativeScrollbarDrag === undefined,
 check(String(arbiter?.modeRef.current) === "tail-follow",
   "a generation reset cannot retain native-thumb ownership");
 
+// A delayed WebView2 range replacement can unmount the logical anchor for a
+// paint while the native extent is collapsed. Keep the accepted viewport
+// visually held from the native scroll delta even though there is no anchor
+// rect to measure yet; otherwise the replacement flashes stale/duplicate
+// transcript pixels until the task settles.
+await act(async () => arbiter?.reset());
+scrollExtent = 5_000;
+scrollElement.scrollTop = 2_000;
+rowElement.getBoundingClientRect = () => rectAt(20);
+await act(async () => arbiter?.deliverScroll());
+await act(async () => arbiter?.releaseTailFollow());
+await act(async () => arbiter?.onWheelIntent({
+  ctrlKey: false,
+  deltaMode: 0,
+  deltaX: 0,
+  deltaY: 24,
+  target: scrollElement,
+} as React.WheelEvent<HTMLElement>));
+scrollExtent = 4_000;
+scrollElement.scrollTop = 1_000;
+rowElement.remove();
+reboundCoverageRow.getBoundingClientRect = () => rectAt(2_000);
+scrollElement.append(reboundCoverageRow);
+await act(async () => arbiter?.deliverScroll());
+check(scrollElement.dataset.transcriptReaderVisualGuard === "true",
+  "a blank range replacement keeps a visual hold while the logical anchor is unmounted");
+reboundCoverageRow.remove();
+scrollElement.append(rowElement);
+
 await act(async () => root.unmount());
 dom.window.close();
 

desktop/frontend/src/__tests__/transcript-scroll-writer.test.ts

@@ -106,6 +106,19 @@ equal(writer.write({
 equal(records[4]?.rejectedReason, "duplicate-revision-phase", "duplicate phases are diagnosable");
 
 geometryRevisionRef.current = 10;
+element.dataset.transcriptReaderIntent = "true";
+geometryRevisionRef.current = 12;
+equal(writer.write({
+  owner: "anchor-compensation",
+  operation: "scrollTo",
+  top: 300,
+  reason: "reader-intent-guard",
+  expectedSurfaceGeneration: 4,
+  expectedOwnershipEpoch: 7,
+  expectedGeometryRevision: 12,
+}), false, "anchor compensation cannot write while reader intent owns the viewport");
+equal(records[5]?.rejectedReason, "reader-intent-owner", "reader-intent suppression is diagnosable");
+delete element.dataset.transcriptReaderIntent;
 
 modeRef.current = "native-thumb";
 equal(writer.write({

desktop/frontend/src/__tests__/transcript-surface-transaction.test.ts

@@ -0,0 +1,32 @@
+import assert from "node:assert/strict";
+import { createTranscriptSurfaceTransactions } from "../lib/transcriptSurfaceTransaction";
+
+const events: Array<{ type: string; fields: Record<string, unknown> }> = [];
+const previous = (globalThis as { window?: Window }).window;
+const windowStub = {
+  __REASONIX_TRANSCRIPT_SCROLL_DIAGNOSTIC__: (type: string, fields: Record<string, unknown>) => events.push({ type, fields }),
+} as unknown as Window;
+(globalThis as { window?: Window }).window = windowStub;
+
+const transactions = createTranscriptSurfaceTransactions();
+const first = transactions.begin({
+  kind: "reader-prepend",
+  surfaceGeneration: 3,
+  ownershipEpoch: 8,
+  geometryRevision: 13,
+  mutationSeq: 21,
+  anchor: { rowKey: "row-a", logicalIndex: 44, viewportOffset: 16 },
+});
+assert.equal(first.token, 1);
+assert.equal(transactions.isCurrent(first.token), true);
+assert.equal(transactions.update(first.token, { phase: "mutating", mutationSeq: 22 }, "prepend"), true);
+assert.equal(transactions.update(first.token - 1, { phase: "settling" }), false);
+assert.equal(transactions.finish(first.token - 1, "committed"), false);
+assert.equal(transactions.finish(first.token, "committed"), true);
+assert.equal(transactions.current(), null);
+assert.deepEqual(events.map((event) => event.fields.result), ["begin", "prepend", "committed"]);
+assert.equal(events[0]?.fields.anchorIndex, 44);
+assert.equal(events[0]?.fields.anchorOffset, 16);
+
+(globalThis as { window?: Window }).window = previous;
+console.log("transcript surface transaction tests passed");