fix(app): preserve timeline bottom anchoring (anomalyco#36160)

Author: Hona

bun.lock

@@ -43,7 +43,7 @@
       "@opentui/core": "0.4.3",
       "@opentui/keymap": "0.4.3",
       "@opentui/solid": "0.4.3",
-      "@tanstack/solid-virtual": "3.13.28",
+      "@tanstack/solid-virtual": "3.13.32",
       "@shikijs/stream": "4.2.0",
       "ulid": "3.0.1",
       "@kobalte/core": "0.13.11",
@@ -152,10 +152,9 @@
     "gcp-metadata@8.1.2": "patches/gcp-metadata@8.1.2.patch",
     "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",
     "@pierre/trees@1.0.0-beta.4": "patches/@pierre%2Ftrees@1.0.0-beta.4.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",
-    "effect@4.0.0-beta.83": "patches/effect@4.0.0-beta.83.patch"
+    "effect@4.0.0-beta.83": "patches/effect@4.0.0-beta.83.patch",
+    "@tanstack/virtual-core@3.17.3": "patches/@tanstack%2Fvirtual-core@3.17.3.patch"
   }
 }

package.json

@@ -1,8 +1,32 @@
 import { expect, test } from "bun:test"
-import { createVirtualizer, defaultRangeExtractor } from "@tanstack/solid-virtual"
+import { createVirtualizer, defaultRangeExtractor, Virtualizer } from "@tanstack/solid-virtual"
 import { createRoot, createSignal } from "solid-js"
 import { filterVirtualIndexes } from "@/pages/session/timeline/virtual-items"
 
+test("end anchoring survives consecutive resizes when the first scroll write is clamped", () => {
+  const writes: { offset: number; adjustments?: number }[] = []
+  const virtualizer = new Virtualizer<HTMLDivElement, HTMLDivElement>({
+    count: 5,
+    estimateSize: () => 50,
+    initialOffset: 50,
+    initialRect: { width: 400, height: 200 },
+    anchorTo: "end",
+    scrollEndThreshold: 1,
+    getScrollElement: () => null,
+    scrollToFn: (offset, options) => writes.push({ offset, adjustments: options.adjustments }),
+    observeElementRect: () => {},
+    observeElementOffset: () => {},
+  })
+
+  virtualizer.getTotalSize()
+  virtualizer.resizeItem(4, 120)
+  expect(writes).toEqual([{ offset: 50, adjustments: 70 }])
+  writes.length = 0
+
+  virtualizer.resizeItem(4, 200)
+  expect(writes).toEqual([{ offset: 120, adjustments: 80 }])
+})
+
 test("reactive count updates preserve measured row sizes", () => {
   createRoot((dispose) => {
     const [count, setCount] = createSignal(2)
@@ -42,23 +66,26 @@ test("initial rect projects rows before a scroll element connects", () => {
   })
 })
 
-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 },
-    })
+test("clamps oversized offsets with scroll margin and padding changes", () => {
+  const options = (paddingEnd: number) => ({
+    count: 20,
+    estimateSize: () => 60,
+    initialOffset: Number.MAX_SAFE_INTEGER,
+    initialRect: { width: 800, height: 600 },
+    scrollMargin: 64,
+    paddingEnd,
+    overscan: 1,
+    getScrollElement: () => null,
+    scrollToFn: () => {},
+    observeElementRect: () => {},
+    observeElementOffset: () => {},
+  })
+  const virtualizer = new Virtualizer<HTMLDivElement, HTMLDivElement>(options(64))
 
-    virtualizer.getTotalSize()
-    virtualizer.resizeItem(0, 100)
+  expect(virtualizer.getVirtualItems().map((item) => item.index)).toEqual([10, 11, 12, 13, 14, 15, 16, 17, 18, 19])
 
-    expect(virtualizer.scrollOffset).toBe(100)
-    expect(virtualizer.getLogicalScrollOffset()).toBe(140)
-    dispose()
-  })
+  virtualizer.setOptions(options(600))
+  expect(virtualizer.getVirtualItems().map((item) => item.index)).toEqual([18, 19])
 })
 
 test("stale pinned indexes do not produce missing virtual items after count shrinks", () => {