fix array modification

README.md

@@ -8,6 +8,7 @@ Core idea: wrap a data tree in a `Proxy` that lazily creates per-property signal
 
 * Lazy: signals & child proxies created only when touched.
 * Deep: nested objects, arrays, Sets proxied on demand.
+  * [ ] TODO: Methods might not be proxied (e.g. array.push)?
 * Per-property signals: fine‑grained invalidation without traversal on each change.
 * Patch stream: microtask‑batched granular mutations (paths + op) for syncing external stores / framework adapters.
 * Getter => computed: property getters become derived (readonly) signals automatically.

src/deepSignal.ts

@@ -644,8 +644,19 @@ const objectHandlers = {
       if (shouldProxy(val)) {
         if (!objToProxy.has(val)) {
           // Link newly wrapped child to its parent for path reconstruction.
-          const parentMeta = proxyMeta.get(receiver)!;
+          // In some edge cases parent metadata might not yet be initialized (e.g.,
-          const childProxy = createProxy(val, objectHandlers, parentMeta.root);
+          // if a proxied structure was reconstructed in a way that bypassed the
+          // original deepSignal root path). Fall back to creating/assigning it.
+          let parentMeta = proxyMeta.get(receiver);
+          if (!parentMeta) {
+            // Assign a root id (new symbol) so downstream patches remain groupable.
+            const created: ProxyMeta = {
+              root: Symbol("deepSignalRootAuto"),
+            } as ProxyMeta;
+            proxyMeta.set(receiver, created);
+            parentMeta = created;
+          }
+          const childProxy = createProxy(val, objectHandlers, parentMeta!.root);
           const childMeta = proxyMeta.get(childProxy)!;
           childMeta.parent = receiver;
           childMeta.key = fullKey;