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fix(web): keep thread switches correct and warm lazy panels #21626

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be73f95
fix(web): keep thread switches correct and warm lazy panels
juliusmarminge Oct 19, 2026
776ec70
test(web): await workflow script highlighting inside act
juliusmarminge Oct 19, 2026
075cdcb
test(web): await attachment source preview before asserting
juliusmarminge Oct 19, 2026
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68 changes: 11 additions & 57 deletions apps/web/src/components/ChatView.logic.test.ts
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -59,13 +59,10 @@ import {
resolveDraftHeroState,
resolveExplicitDiffOpenOnActivate,
resolveWorktreeSetupProgress,
isPaintOnlyThreadTimeline,
peekHeldThreadTimeline,
peekRememberedThreadTimeline,
rememberReadyThreadTimeline,
resetHeldThreadTimeline,
resetRememberedThreadTimelines,
resolveThreadSwitchTimeline,
threadKeysShareEnvironment,
timelineHasEphemeralPreviewUrls,
scheduleEnvironmentReconnectWarning,
codexArtifactTemplatePromptToAppend,
Expand Down Expand Up @@ -1038,31 +1035,31 @@ describe("draft hero submission transition", () => {

describe("resolveThreadSwitchTimeline", () => {
afterEach(() => {
resetHeldThreadTimeline();
resetRememberedThreadTimelines();
});

const held = { threadKey: "env-1:thread-a", entries: ["a1", "a2"] };

it("keeps the previous thread's entries while the next thread is loading", () => {
it("leaves the destination empty while its first snapshot is loading", () => {
rememberReadyThreadTimeline(held);
expect(
resolveThreadSwitchTimeline({
loading: true,
activeThreadKey: "env-1:thread-b",
nextEntries: [],
lastReady: held,
}),
).toEqual({ entries: ["a1", "a2"], displayThreadKey: "env-1:thread-a" });
).toEqual([]);
});

it("shows the new thread once its detail is ready", () => {
rememberReadyThreadTimeline(held);
expect(
resolveThreadSwitchTimeline({
loading: false,
activeThreadKey: "env-1:thread-b",
nextEntries: ["b1"],
lastReady: held,
}),
).toEqual({ entries: ["b1"], displayThreadKey: "env-1:thread-b" });
).toEqual(["b1"]);
});

it("does not invent a timeline on the first open of a thread", () => {
Expand All @@ -1071,34 +1068,8 @@ describe("resolveThreadSwitchTimeline", () => {
loading: true,
activeThreadKey: "env-1:thread-a",
nextEntries: [],
lastReady: null,
}),
).toEqual({ entries: [], displayThreadKey: "env-1:thread-a" });
});

it("keeps the held thread workspace cwd with the snapshot", () => {
rememberReadyThreadTimeline({
...held,
markdownCwd: "/repo/a",
workspaceRoot: "/repo/a",
});
expect(peekHeldThreadTimeline<string[]>()).toEqual({
...held,
markdownCwd: "/repo/a",
workspaceRoot: "/repo/a",
});
});

it("survives a ChatView remount by remembering the last ready timeline", () => {
rememberReadyThreadTimeline(held);
expect(peekHeldThreadTimeline<string[]>()).toEqual(held);
expect(
resolveThreadSwitchTimeline({
loading: true,
activeThreadKey: "env-1:thread-b",
nextEntries: [],
}),
).toEqual({ entries: ["a1", "a2"], displayThreadKey: "env-1:thread-a" });
).toEqual([]);
});

it("paints a remembered destination instead of the last-viewed thread", () => {
Expand All @@ -1111,7 +1082,7 @@ describe("resolveThreadSwitchTimeline", () => {
activeThreadKey: "env-1:thread-a",
nextEntries: [],
}),
).toEqual({ entries: ["a1", "a2"], displayThreadKey: "env-1:thread-a" });
).toEqual(["a1", "a2"]);
});

it("prefers live entries over a remembered snapshot", () => {
Expand All @@ -1122,7 +1093,7 @@ describe("resolveThreadSwitchTimeline", () => {
activeThreadKey: "env-1:thread-b",
nextEntries: ["fresh-b"],
}),
).toEqual({ entries: ["fresh-b"], displayThreadKey: "env-1:thread-b" });
).toEqual(["fresh-b"]);
});

it("does not keep a remembered snapshot on a resolved empty thread", () => {
Expand All @@ -1133,24 +1104,7 @@ describe("resolveThreadSwitchTimeline", () => {
activeThreadKey: "env-1:thread-a",
nextEntries: [],
}),
).toEqual({ entries: [], displayThreadKey: "env-1:thread-a" });
});

it("does not hold another environment's timeline across a jump", () => {
expect(threadKeysShareEnvironment("env-1:thread-a", "env-2:thread-b")).toBe(false);
expect(
resolveThreadSwitchTimeline({
loading: true,
activeThreadKey: "env-2:thread-b",
nextEntries: [],
lastReady: held,
}),
).toEqual({ entries: [], displayThreadKey: "env-2:thread-b" });
});

it("treats a foreign held timeline as paint-only", () => {
expect(isPaintOnlyThreadTimeline("env-1:thread-a", "env-1:thread-b")).toBe(true);
expect(isPaintOnlyThreadTimeline("env-1:thread-b", "env-1:thread-b")).toBe(false);
).toEqual([]);
});

it("does not remember a timeline that still has handoff blob previews", () => {
Expand Down
123 changes: 18 additions & 105 deletions apps/web/src/components/ChatView.logic.ts
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -28,7 +28,6 @@ import {
} from "@t3tools/contracts";
import { worktreeSetupAgentStarted } from "@t3tools/client-runtime/worktree-setup";
import * as DateTime from "effect/DateTime";
import { parseScopedThreadKey } from "@t3tools/client-runtime/environment";
import { resolveAssetUrl } from "@t3tools/client-runtime/state/assets";
import {
squashAtomCommandFailure,
Expand Down Expand Up @@ -320,126 +319,40 @@ export function resolveDraftHeroState(input: {
);
}

/**
* Remounting LegendList (or handing it an empty first paint) punches a hole
* through the chat pane — white in light mode — so cmd+1/2/3 spam flashes even
* when the destination is already cached.
*/
export type HeldThreadTimeline<T extends readonly unknown[]> = {
threadKey: string | null;
entries: T;
markdownCwd?: string | null;
workspaceRoot?: string | null;
};

const MAX_REMEMBERED_THREAD_TIMELINES = 16;
const rememberedThreadTimelines = new Map<string, readonly unknown[]>();

let rememberedThreadTimelines = new Map<string, HeldThreadTimeline<readonly unknown[]>>();
let rememberedThreadTimelineOrder: string[] = [];
let lastReadyThreadKey: string | null = null;

function rememberThreadTimelineEntries(held: HeldThreadTimeline<readonly unknown[]>): void {
if (held.threadKey === null) {
return;
}
rememberedThreadTimelines.set(held.threadKey, held);
rememberedThreadTimelineOrder = [
...rememberedThreadTimelineOrder.filter((key) => key !== held.threadKey),
held.threadKey,
];
while (rememberedThreadTimelineOrder.length > MAX_REMEMBERED_THREAD_TIMELINES) {
const evicted = rememberedThreadTimelineOrder.shift();
if (evicted !== undefined) {
rememberedThreadTimelines.delete(evicted);
}
}
lastReadyThreadKey = held.threadKey;
}

export function rememberReadyThreadTimeline<T extends readonly unknown[]>(
held: HeldThreadTimeline<T>,
): void {
if (held.threadKey === null || held.entries.length === 0) {
return;
export function rememberReadyThreadTimeline<T extends readonly unknown[]>(input: {
threadKey: string | null;
entries: T;
}): void {
if (input.threadKey === null || input.entries.length === 0) return;
rememberedThreadTimelines.delete(input.threadKey);
rememberedThreadTimelines.set(input.threadKey, input.entries);
if (rememberedThreadTimelines.size > MAX_REMEMBERED_THREAD_TIMELINES) {
const oldest = rememberedThreadTimelines.keys().next().value;
if (oldest !== undefined) rememberedThreadTimelines.delete(oldest);
}
rememberThreadTimelineEntries(held);
}

export function peekRememberedThreadTimeline<T extends readonly unknown[]>(
threadKey: string | null,
): T | null {
if (threadKey === null) {
return null;
}
return (rememberedThreadTimelines.get(threadKey)?.entries as T | undefined) ?? null;
if (threadKey === null) return null;
return (rememberedThreadTimelines.get(threadKey) as T | undefined) ?? null;
}

export function peekHeldThreadTimeline<
T extends readonly unknown[],
>(): HeldThreadTimeline<T> | null {
if (lastReadyThreadKey === null) {
return null;
}
const held = rememberedThreadTimelines.get(lastReadyThreadKey);
if (held === undefined || held.entries.length === 0) {
return null;
}
return held as HeldThreadTimeline<T>;
}

export function resetHeldThreadTimeline(): void {
rememberedThreadTimelines = new Map();
rememberedThreadTimelineOrder = [];
lastReadyThreadKey = null;
}

export function threadKeysShareEnvironment(left: string | null, right: string | null): boolean {
if (left === null || right === null) {
return false;
}
const leftRef = parseScopedThreadKey(left);
const rightRef = parseScopedThreadKey(right);
return leftRef !== null && rightRef !== null && leftRef.environmentId === rightRef.environmentId;
}

export function isPaintOnlyThreadTimeline(
displayThreadKey: string | null,
activeThreadKey: string | null,
): boolean {
return (
displayThreadKey !== null && activeThreadKey !== null && displayThreadKey !== activeThreadKey
);
export function resetRememberedThreadTimelines(): void {
rememberedThreadTimelines.clear();
}

export function resolveThreadSwitchTimeline<T extends readonly unknown[]>(input: {
loading: boolean;
activeThreadKey: string | null;
nextEntries: T;
rememberedForActive?: T | null;
lastReady?: HeldThreadTimeline<T> | null;
}): { entries: T; displayThreadKey: string | null } {
if (input.nextEntries.length > 0) {
return { entries: input.nextEntries, displayThreadKey: input.activeThreadKey };
}

const rememberedForActive =
input.rememberedForActive ?? peekRememberedThreadTimeline<T>(input.activeThreadKey);
if (input.loading && rememberedForActive !== null && rememberedForActive.length > 0) {
return { entries: rememberedForActive, displayThreadKey: input.activeThreadKey };
}

const lastReady = input.lastReady ?? peekHeldThreadTimeline<T>();
if (
input.loading &&
lastReady !== null &&
lastReady.threadKey !== null &&
lastReady.threadKey !== input.activeThreadKey &&
lastReady.entries.length > 0 &&
threadKeysShareEnvironment(lastReady.threadKey, input.activeThreadKey)
) {
return { entries: lastReady.entries, displayThreadKey: lastReady.threadKey };
}
return { entries: input.nextEntries, displayThreadKey: input.activeThreadKey };
}): T {
if (input.nextEntries.length > 0 || !input.loading) return input.nextEntries;
return peekRememberedThreadTimeline<T>(input.activeThreadKey) ?? input.nextEntries;
}

export function resolveDraftPromotionNavigationTarget(input: {
Expand Down
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