Fix for resizable side panel getting stuck at its min-size

Author: samejr

.server-changes/fix-resizable-panel-stuck.md

@@ -0,0 +1,6 @@
+---
+area: webapp
+type: fix
+---
+
+Fix the run-view inspector panel locking at minimum width on reload when the persisted layout snapshot is in a state the underlying library can't safely restore.

apps/webapp/app/components/primitives/Resizable.tsx

@@ -4,15 +4,78 @@ import React, { useRef } from "react";
 import { PanelGroup, Panel, PanelResizer } from "react-window-splitter";
 import { cn } from "~/utils/cn";
 
-const ResizablePanelGroup = ({ className, ...props }: React.ComponentProps<typeof PanelGroup>) => (
-  <PanelGroup
-    className={cn(
-      "flex w-full overflow-hidden data-[panel-group-direction=vertical]:flex-col",
-      className
-    )}
-    {...props}
-  />
-);
+const ResizablePanelGroup = ({
+  className,
+  autosaveId,
+  snapshot: snapshotProp,
+  ...props
+}: React.ComponentProps<typeof PanelGroup>) => {
+  return (
+    <PanelGroup
+      className={cn(
+        "flex w-full overflow-hidden data-[panel-group-direction=vertical]:flex-col",
+        className
+      )}
+      autosaveId={autosaveId}
+      snapshot={getSafeSnapshot(autosaveId, snapshotProp)}
+      {...props}
+    />
+  );
+};
+
+// react-window-splitter reads the persisted snapshot from localStorage during
+// render and feeds it straight into prepareSnapshot + the state machine. If the
+// value is corrupt (extension interference, JSON parse failure) or in a shape
+// the library can't safely consume on restore — notably items committed with
+// percent-typed currentValues, which trip a `panelHasSpace only works with
+// number values` invariant on the next expand — the panel locks at min size
+// with no working drag.
+//
+// We read the snapshot ourselves with try/catch + structural validation. On
+// failure we pass `true` (the library's sentinel for "snapshot already
+// resolved") so it skips its own localStorage read and falls back to defaults.
+// Pure read — safe to call on every render. PanelGroup captures via useState
+// on first render, so later calls are wasted work but never wrong.
+function getSafeSnapshot(
+  autosaveId: string | undefined,
+  ssrSnapshot: React.ComponentProps<typeof PanelGroup>["snapshot"]
+) {
+  if (typeof window === "undefined") return ssrSnapshot;
+  if (ssrSnapshot && isValidSnapshot(ssrSnapshot)) return ssrSnapshot;
+  if (!autosaveId) return undefined;
+
+  try {
+    const raw = window.localStorage.getItem(autosaveId);
+    if (!raw) return SNAPSHOT_RESOLVED;
+    const parsed: unknown = JSON.parse(raw);
+    if (!isValidSnapshot(parsed)) return SNAPSHOT_RESOLVED;
+    return parsed as React.ComponentProps<typeof PanelGroup>["snapshot"];
+  } catch {
+    return SNAPSHOT_RESOLVED;
+  }
+}
+
+const SNAPSHOT_RESOLVED = true as unknown as React.ComponentProps<typeof PanelGroup>["snapshot"];
+
+function isValidSnapshot(value: unknown): boolean {
+  if (!value || typeof value !== "object") return false;
+  const obj = value as Record<string, unknown>;
+  if (!("status" in obj) || !("context" in obj)) return false;
+  const ctx = obj.context as Record<string, unknown> | null;
+  if (!ctx || typeof ctx !== "object" || !Array.isArray(ctx.items)) return false;
+
+  for (const item of ctx.items) {
+    if (!item || typeof item !== "object") return false;
+    const it = item as Record<string, unknown>;
+    if (it.type !== "panel") continue;
+    const cv = it.currentValue as Record<string, unknown> | null;
+    if (!cv || typeof cv !== "object" || cv.type !== "pixel") return false;
+    // value must be numeric (number or numeric string) so prepareSnapshot's
+    // `new Big(value)` rehydration can't throw on us.
+    if (typeof cv.value !== "string" && typeof cv.value !== "number") return false;
+  }
+  return true;
+}
 
 const ResizablePanel = Panel;
 
@@ -71,7 +134,7 @@ const ResizableHandle = ({
 
 const RESIZABLE_PANEL_ANIMATION = {
   easing: "ease-in-out" as const,
-  duration: 200,
+  duration: 300,
 };
 
 const COLLAPSIBLE_HANDLE_CLASSNAME = "transition-opacity duration-200";