From 0d1406fe9a843405c664d1c1dac7e76771edc1ae Mon Sep 17 00:00:00 2001
From: Andrew Kolos <andrewrkolos@gmail.com>
Date: Wed, 11 Feb 2026 14:08:31 -0800
Subject: [PATCH] fix: parse adjacency-list values for non-root paths

In `DataModel.update`, `_parseDataModelContents` was only called when the path was the root. For non-root paths, this caused a TypeError when a widget subscribed to that path expecting a map since the stored value was still the raw A2UI adjacency list format.
---
 packages/genui/lib/src/model/data_model.dart   |  8 ++++++--
 packages/genui/test/model/data_model_test.dart | 16 ++++++++++++++++
 2 files changed, 22 insertions(+), 2 deletions(-)

diff --git a/packages/genui/lib/src/model/data_model.dart b/packages/genui/lib/src/model/data_model.dart
index e00fc7298..ee7038fbe 100644
--- a/packages/genui/lib/src/model/data_model.dart
+++ b/packages/genui/lib/src/model/data_model.dart
@@ -129,9 +129,13 @@ class DataModel {
       'DataModel.update: path=$absolutePath, contents='
       '${const JsonEncoder.withIndent('  ').convert(contents)}',
     );
+    final Object? parsedContents = contents is List
+        ? _parseDataModelContents(contents)
+        : contents;
+
     if (absolutePath == null || absolutePath.segments.isEmpty) {
       if (contents is List) {
-        _data = _parseDataModelContents(contents);
+        _data = parsedContents as Map<String, Object?>;
       } else if (contents is Map) {
         // Permissive: Allow a map to be sent for the root, even though the
         // schema expects a list.
@@ -151,7 +155,7 @@ class DataModel {
       return;
     }
 
-    _updateValue(_data, absolutePath.segments, contents);
+    _updateValue(_data, absolutePath.segments, parsedContents);
     _notifySubscribers(absolutePath);
   }
 
diff --git a/packages/genui/test/model/data_model_test.dart b/packages/genui/test/model/data_model_test.dart
index a7540bb02..278cdd3a2 100644
--- a/packages/genui/test/model/data_model_test.dart
+++ b/packages/genui/test/model/data_model_test.dart
@@ -257,6 +257,22 @@ void main() {
         ]);
         expect(dataModel.getValue<Object?>(DataPath('/f')), isNull);
       });
+
+      test('parses contents for non-root paths', () {
+        dataModel.update(DataPath('/todos'), <Object?>[
+          {
+            'key': '0',
+            'valueMap': <Object?>[
+              {'key': 'id', 'valueString': 'abc'},
+              {'key': 'title', 'valueString': 'Buy groceries'},
+            ],
+          },
+        ]);
+        expect(
+          dataModel.getValue<Map<Object?, Object?>>(DataPath('/todos/0')),
+          {'id': 'abc', 'title': 'Buy groceries'},
+        );
+      });
     });
   });