fix: never pass -0 or NaN to BrowserWindow.setPosition

apps/desktop/src/agent-pet-controller.ts

@@ -10,6 +10,7 @@ import { transientDisplayMs, type OpenPetsReaction } from "./local-ipc-protocol.
 import { clearTransientReaction, createAgentPetWindow, getTransientDisplayDurationMs, getTransientReactionAnimationMs, loadExplicitPetContent, mergePetTransientDisplay, readWindowPosition, setPetReactionState, showPetWindowInactive, type PetShowMediaOptions, type PetTransientDisplay } from "./pet-window.js";
 import { focusTerminalWindow } from "./terminal-focus.js";
 import { createPetTransientPresentation, type PetTransientPresentation } from "./pet-transient-presentation.js";
+import { setWindowPosition } from "./window-position.js";
 
 const agentPetWindows = new Map<string, BrowserWindow>();
 const transientPresentations = new Map<string, PetTransientPresentation>();
@@ -48,7 +49,7 @@ export function repositionConfinedPet(petId: string, win?: BrowserWindow): void
   const clamped = clampToTerminalBounds({ x: cx, y: cy }, defaultPetWindowSize, confinementBounds);
   if (clamped.x !== cx || clamped.y !== cy) {
     debug("pet.agent", "reposition confined", { petId, from: { x: cx, y: cy }, to: clamped });
-    window.setPosition(clamped.x, clamped.y, false);
+    setWindowPosition(window, clamped.x, clamped.y, false);
   }
 }
 
@@ -141,7 +142,7 @@ export function reclampAgentPetWindows(reason?: DisplayChangeReason): void {
     const [currentX, currentY] = window.getPosition();
     if (safePosition.x !== currentX || safePosition.y !== currentY) {
       info("pet.agent", "reclamp position", { petId, windowId: window.id, from: { x: currentX, y: currentY }, to: safePosition });
-      window.setPosition(safePosition.x, safePosition.y, false);
+      setWindowPosition(window, safePosition.x, safePosition.y, false);
     }
   }
   // A live display-scale change invalidates the Linux setShape() click-through

apps/desktop/src/default-pet-controller.ts

@@ -16,6 +16,7 @@ import { composeVoiceActivityBadge, composeVoiceActivityDisplay } from "./voice-
 import { createPetTransientPresentation, type PetTransientPresentation } from "./pet-transient-presentation.js";
 import type { ManagerCheckInOffer } from "./manager-check-in-service.js";
 import type { DisplayChangeReason } from "./pet-display-coordinator.js";
+import { setWindowPosition } from "./window-position.js";
 
 let defaultPetWindow: BrowserWindow | null = null;
 let paused = false;
@@ -514,10 +515,10 @@ async function moveDefaultPetBy(rawX: number, rawY: number, rawDurationMs: unkno
       const blocked = getMovementBlockedReason(window, true);
       if (blocked) return { moved: false, reason: blocked };
       const t = step / steps;
-      window.setPosition(Math.round(current.x + (target.x - current.x) * t), Math.round(current.y + (target.y - current.y) * t), false);
+      setWindowPosition(window, Math.round(current.x + (target.x - current.x) * t), Math.round(current.y + (target.y - current.y) * t), false);
       await delay(durationMs / steps);
     }
-    window.setPosition(target.x, target.y, false);
+    setWindowPosition(window, target.x, target.y, false);
     handlePositionChanged(target);
     debug("pet.default", "move finished", { windowId: window.id, target });
     return { moved: true };
@@ -604,7 +605,7 @@ export function reclampDefaultPetWindow(reason: DisplayChangeReason, changedDisp
     : getSafeDefaultPetPosition(currentPosition);
 
   info("pet.default", "reclamp position", { windowId: defaultPetWindow.id, position: safePosition, restored: Boolean(restoredPosition), reason, changedDisplayKey });
-  defaultPetWindow.setPosition(safePosition.x, safePosition.y, false);
+  setWindowPosition(defaultPetWindow, safePosition.x, safePosition.y, false);
   handlePositionChanged(safePosition);
   recoverDefaultPetMouseInterop("display-change");
   // A live display-scale change invalidates the Linux setShape() click-through mask
@@ -626,6 +627,6 @@ export function resetDefaultPetToInitialPosition(): void {
   resetDefaultPetPosition(safePosition);
 
   if (defaultPetWindow && !defaultPetWindow.isDestroyed()) {
-    defaultPetWindow.setPosition(safePosition.x, safePosition.y, false);
+    setWindowPosition(defaultPetWindow, safePosition.x, safePosition.y, false);
   }
 }

apps/desktop/src/lan-pet-controller.ts

@@ -8,6 +8,7 @@ import type { LanPetRecord, LanPoint } from "./lan-contract.js";
 import { createAgentPetWindow, getTransientDisplayDurationMs, loadExplicitPetContent, readWindowPosition, showPetWindowInactive, type PetTransientDisplay } from "./pet-window.js";
 import type { OpenPetsReaction } from "./local-ipc-protocol.js";
 import { registerRoamingPet, unregisterRoamingPet } from "./pet-roaming-controller.js";
+import { setWindowPosition } from "./window-position.js";
 
 type VisitingPetWindow = {
   readonly ownerHost: string;
@@ -83,7 +84,7 @@ export function reclampLanVisitingPetWindows(): void {
     if (entry.window.isDestroyed()) continue;
     const safe = readWindowPosition(entry.window);
     const [x, y] = entry.window.getPosition();
-    if (safe.x !== x || safe.y !== y) entry.window.setPosition(safe.x, safe.y, false);
+    if (safe.x !== x || safe.y !== y) setWindowPosition(entry.window, safe.x, safe.y, false);
   }
 }
 

apps/desktop/src/pet-window-context-menu.ts

@@ -27,6 +27,7 @@ import {
 } from "./plugin-service.js";
 import type { PluginCommandForm } from "./plugin-sdk-bridge.js";
 import { escapeHtml } from "./pet-window-render.js";
+import { setWindowPosition } from "./window-position.js";
 
 export function installPetContextMenu(
   window: BrowserWindow,
@@ -429,7 +430,7 @@ async function openPluginCommandForm(
       display.workArea.y + display.workArea.height - bounds.height,
     );
     if (nextX !== bounds.x || nextY !== bounds.y) {
-      window.setPosition(Math.round(nextX), Math.round(nextY));
+      setWindowPosition(window, nextX, nextY);
     }
   });
   window.once("closed", () => {

apps/desktop/src/plugin-delivery.ts

@@ -2,6 +2,7 @@ import type { BrowserWindow } from "electron";
 import { createRequire } from "node:module";
 import { join } from "node:path";
 import { getDisplayKey } from "./display.js";
+import { setWindowPosition } from "./window-position.js";
 
 const require = createRequire(import.meta.url);
 
@@ -807,7 +808,7 @@ async function createOrUpdateAirmailWindow(displayKey: string, activeItem: Queue
       await window.loadURL(targetUrl);
 
       if (window.isDestroyed() || getActiveItem()?.generationId !== activeItem.generationId) return;
-      window.setPosition(x_start, y_pos);
+      setWindowPosition(window, x_start, y_pos);
       window.showInactive();
       const [visibleXStart, visibleYStart] = window.getPosition();
       logDebug("ui", "delivery flight starts from visible window position", { displayKey, requestedXStart: x_start, requestedYStart: y_pos, visibleXStart, visibleYStart, xEnd: x_end });
@@ -837,7 +838,7 @@ async function createOrUpdateAirmailWindow(displayKey: string, activeItem: Queue
         const t = easeLinear(progress);
         const x = Math.round(visibleXStart + (x_end - visibleXStart) * t);
 
-        window.setPosition(x, visibleYStart);
+        setWindowPosition(window, x, visibleYStart);
 
         if (progress >= 1) {
           clearInterval(animTimer);
@@ -866,7 +867,7 @@ async function createOrUpdateAirmailWindow(displayKey: string, activeItem: Queue
       await window.loadURL(targetUrl);
       if (window.isDestroyed() || getActiveItem()?.generationId !== activeItem.generationId) return;
       // Set straight to parked/waiting if we did an in-place update
-      window.setPosition(x_end, y_pos);
+      setWindowPosition(window, x_end, y_pos);
       window.webContents.send("openpets:pet-reaction-state", "waiting");
     }
   } catch (err) {

apps/desktop/src/plugin-pet-registry.ts

@@ -13,6 +13,7 @@ import { publishPluginPetEvent } from "./plugin-events-source.js";
 import { resolveReactionSpriteState } from "./reaction-animation-mapping.js";
 import type { PluginAnimationSpec, PluginPetInfo, PluginPetState } from "./plugin-sdk-bridge.js";
 import type { DisplayChangeReason } from "./pet-display-coordinator.js";
+import { setWindowPosition } from "./window-position.js";
 
 /**
  * Multi-pet registry (§4): addressable pet handles for plugins. "default" is
@@ -367,7 +368,7 @@ export function reclampPluginPetWindows(reason?: DisplayChangeReason): void {
     if (!window || window.isDestroyed()) continue;
     const [cx, cy] = window.getPosition();
     const safe = readWindowPosition(window);
-    if (safe.x !== cx || safe.y !== cy) window.setPosition(safe.x, safe.y, false);
+    if (safe.x !== cx || safe.y !== cy) setWindowPosition(window, safe.x, safe.y, false);
     // A live display-scale change invalidates the Linux setShape() click-through
     // mask for plugin pet windows too, not just the default pet -- see the
     // matching fix in default-pet-controller.ts's reclampDefaultPetWindow().

apps/desktop/src/window-position.ts

@@ -0,0 +1,27 @@
+import type { BrowserWindow } from "electron";
+
+/**
+ * Electron's BrowserWindow.setPosition rejects -0 and non-finite numbers with
+ * "Error processing argument at index N, conversion failure from", which
+ * surfaces as an uncaught main-process exception. Math.round() returns -0 for
+ * values in [-0.5, 0), so any animation that crosses x=0 or y=0 can hit it.
+ */
+export function toWindowCoordinate(value: number): number | null {
+  if (!Number.isFinite(value)) return null;
+  return Math.round(value) + 0; // + 0 turns -0 into 0
+}
+
+/** setPosition that never throws on -0/NaN. Returns false if the move was skipped. */
+export function setWindowPosition(
+  window: Pick<BrowserWindow, "setPosition">,
+  x: number,
+  y: number,
+  animate?: boolean,
+): boolean {
+  const safeX = toWindowCoordinate(x);
+  const safeY = toWindowCoordinate(y);
+  if (safeX === null || safeY === null) return false;
+  if (animate === undefined) window.setPosition(safeX, safeY);
+  else window.setPosition(safeX, safeY, animate);
+  return true;
+}

apps/desktop/tests/window-position.test.ts

@@ -0,0 +1,50 @@
+/**
+ * Unit tests for window-position.ts.
+ *
+ * Electron's setPosition throws on -0 and NaN; setWindowPosition must never
+ * pass either through. No Electron process is required.
+ */
+
+import assert from "node:assert/strict";
+
+import { setWindowPosition, toWindowCoordinate } from "../src/window-position.js";
+
+function recorder() {
+  const calls: unknown[][] = [];
+  return { calls, window: { setPosition: (...args: unknown[]) => { calls.push(args); } } as any };
+}
+
+// Math.round(-0.3) is -0; the helper must hand Electron a plain 0.
+assert.ok(Object.is(Math.round(-0.3), -0), "precondition: Math.round yields -0");
+assert.ok(Object.is(toWindowCoordinate(-0.3), 0), "-0.3 -> +0");
+assert.ok(Object.is(toWindowCoordinate(-0), 0), "-0 -> +0");
+assert.equal(toWindowCoordinate(-480), -480);
+assert.equal(toWindowCoordinate(12.6), 13);
+assert.equal(toWindowCoordinate(Number.NaN), null);
+assert.equal(toWindowCoordinate(Number.POSITIVE_INFINITY), null);
+
+// Airmail flight: -480 -> 2064 over 15 s at 16 ms ticks. Tick 176 (2828 ms) rounds to -0.
+{
+  const { calls, window } = recorder();
+  const x = Math.round(-480 + (2064 - -480) * (2828 / 15_000));
+  assert.ok(Object.is(x, -0), "precondition: airmail tick lands on -0");
+  assert.equal(setWindowPosition(window, x, 240), true);
+  assert.ok(Object.is(calls[0]?.[0], 0), "airmail -0 passed through as +0");
+  assert.deepEqual(calls[0], [0, 240]);
+}
+
+// animate flag is forwarded only when given.
+{
+  const { calls, window } = recorder();
+  setWindowPosition(window, 10, 20, false);
+  assert.deepEqual(calls[0], [10, 20, false]);
+}
+
+// Non-finite coordinates skip the move instead of throwing.
+{
+  const { calls, window } = recorder();
+  assert.equal(setWindowPosition(window, Number.NaN, 0), false);
+  assert.equal(calls.length, 0);
+}
+
+console.error("window-position.test.ts: all window position tests passed.");