fix(app): account for pending scroll adjustments

bun.lock

@@ -917,6 +917,7 @@
     "@tanstack/solid-virtual@3.13.28": "patches/@tanstack%2Fsolid-virtual@3.13.28.patch",
     "@ai-sdk/xai@3.0.82": "patches/@ai-sdk%2Fxai@3.0.82.patch",
     "pacote@21.5.0": "patches/pacote@21.5.0.patch",
+    "@tanstack/virtual-core@3.17.0": "patches/@tanstack%2Fvirtual-core@3.17.0.patch",
     "@standard-community/standard-openapi@0.2.9": "patches/@standard-community%2Fstandard-openapi@0.2.9.patch",
     "@modelcontextprotocol/sdk@1.29.0": "patches/@modelcontextprotocol%2Fsdk@1.29.0.patch",
     "gcp-metadata@8.1.2": "patches/gcp-metadata@8.1.2.patch",

package.json

@@ -151,6 +151,7 @@
     "pacote@21.5.0": "patches/pacote@21.5.0.patch",
     "@ai-sdk/google@3.0.73": "patches/@ai-sdk%2Fgoogle@3.0.73.patch",
     "@tanstack/solid-virtual@3.13.28": "patches/@tanstack%2Fsolid-virtual@3.13.28.patch",
-    "@modelcontextprotocol/sdk@1.29.0": "patches/@modelcontextprotocol%2Fsdk@1.29.0.patch"
+    "@modelcontextprotocol/sdk@1.29.0": "patches/@modelcontextprotocol%2Fsdk@1.29.0.patch",
+    "@tanstack/virtual-core@3.17.0": "patches/@tanstack%2Fvirtual-core@3.17.0.patch"
   }
 }

packages/app/src/pages/session/timeline/message-timeline.tsx

@@ -473,7 +473,7 @@ export function MessageTimeline(props: {
     resizeItem(index, size)
   }
   virtualizer.shouldAdjustScrollPositionOnItemSizeChange = (item, _delta, instance) =>
-    item.end <= (instance.scrollOffset ?? 0)
+    item.end <= instance.getLogicalScrollOffset()
   const virtualItemByKey = createMemo(
     () => new Map(virtualizer.getVirtualItems().map((item) => [item.key, item] as const)),
   )

packages/app/test-browser/solid-virtual.test.ts

@@ -25,3 +25,22 @@ test("reactive count updates preserve measured row sizes", () => {
     dispose()
   })
 })
+
+test("logical scroll offset includes pending measurement adjustments", () => {
+  createRoot((dispose) => {
+    const virtualizer = createVirtualizer<HTMLDivElement, HTMLDivElement>({
+      count: 2,
+      getScrollElement: () => null,
+      estimateSize: () => 60,
+      initialOffset: 100,
+      initialRect: { width: 800, height: 60 },
+    })
+
+    virtualizer.getTotalSize()
+    virtualizer.resizeItem(0, 100)
+
+    expect(virtualizer.scrollOffset).toBe(100)
+    expect(virtualizer.getLogicalScrollOffset()).toBe(140)
+    dispose()
+  })
+})

patches/@tanstack%2Fvirtual-core@3.17.0.patch

@@ -0,0 +1,61 @@
+diff --git a/dist/cjs/index.cjs b/dist/cjs/index.cjs
+index df75d0cf0347b62906e04e454d4f4ef062ed5c48..58913f2d30e0beee9d09dffa5ebcaab4601a2c22 100644
+--- a/dist/cjs/index.cjs
++++ b/dist/cjs/index.cjs
+@@ -526,6 +526,7 @@ class Virtualizer {
+       this.scrollOffset = this.scrollOffset ?? (typeof this.options.initialOffset === "function" ? this.options.initialOffset() : this.options.initialOffset);
+       return this.scrollOffset;
+     };
++    this.getLogicalScrollOffset = () => this.getScrollOffset() + this.scrollAdjustments;
+     this.getFurthestMeasurement = (measurements, index) => {
+       const furthestMeasurementsFound = /* @__PURE__ */ new Map();
+       const furthestMeasurements = /* @__PURE__ */ new Map();
+diff --git a/dist/cjs/index.d.cts b/dist/cjs/index.d.cts
+index c61ee17752565253f795c7fc7d57e86237ecbb52..705bb7e3a121b040fb1a3e7890179eaa3e9b219e 100644
+--- a/dist/cjs/index.d.cts
++++ b/dist/cjs/index.d.cts
+@@ -108,6 +108,7 @@ export declare class Virtualizer<TScrollElement extends Element | Window, TItemE
+     scrollRect: Rect | null;
+     scrollOffset: number | null;
+     scrollDirection: ScrollDirection | null;
++    getLogicalScrollOffset: () => number;
+     private scrollAdjustments;
+     private _iosDeferredAdjustment;
+     private _iosTouching;
+diff --git a/dist/esm/index.d.ts b/dist/esm/index.d.ts
+index b03abab604eb6578f6f56ff92c489259cfaf8f19..0495f372ea000dffc416c4f56809946f7ba73099 100644
+--- a/dist/esm/index.d.ts
++++ b/dist/esm/index.d.ts
+@@ -108,6 +108,7 @@ export declare class Virtualizer<TScrollElement extends Element | Window, TItemE
+     scrollRect: Rect | null;
+     scrollOffset: number | null;
+     scrollDirection: ScrollDirection | null;
++    getLogicalScrollOffset: () => number;
+     private scrollAdjustments;
+     private _iosDeferredAdjustment;
+     private _iosTouching;
+diff --git a/dist/esm/index.js b/dist/esm/index.js
+index e384cf7541978a2782b9dca68146e869b16ac3f2..53b15b7a36247ea4aa5b70b00d08b6d7dec3ea79 100644
+--- a/dist/esm/index.js
++++ b/dist/esm/index.js
+@@ -524,6 +524,7 @@ class Virtualizer {
+       this.scrollOffset = this.scrollOffset ?? (typeof this.options.initialOffset === "function" ? this.options.initialOffset() : this.options.initialOffset);
+       return this.scrollOffset;
+     };
++    this.getLogicalScrollOffset = () => this.getScrollOffset() + this.scrollAdjustments;
+     this.getFurthestMeasurement = (measurements, index) => {
+       const furthestMeasurementsFound = /* @__PURE__ */ new Map();
+       const furthestMeasurements = /* @__PURE__ */ new Map();
+diff --git a/src/index.ts b/src/index.ts
+index d35b3e0695a9c85b261bc1a4fbe23c0a60d5b204..d516a9d00f1233173f9a3e2144666c8159552f91 100644
+--- a/src/index.ts
++++ b/src/index.ts
+@@ -1047,6 +1047,8 @@ export class Virtualizer<
+     return this.scrollOffset
+   }
+ 
++  getLogicalScrollOffset = () => this.getScrollOffset() + this.scrollAdjustments
++
+   private getFurthestMeasurement = (
+     measurements: Array<VirtualItem>,
+     index: number,