From 776caab1fd6ec3b4c50b7dbd86e63e53b66b3603 Mon Sep 17 00:00:00 2001
From: Sanjay Santhanam <51058514+Sanjays2402@users.noreply.github.com>
Date: Sun, 2 Aug 2026 05:12:31 -0700
Subject: [PATCH] Serialize bytes values in diagnostics JSON

ZhaJsonEncoder only special-cased set, so any bytes value reaching
Device.get_diagnostics_json() made the whole diagnostics JSON
unserializable. Quirks v2 can put bytes there via command_button's
command_args and write_attr_button's attribute_value, so devices using
either could never be imported into tests/data/devices/ and got no
coverage from test_devices_from_files.

Emit Home Assistant's {"__type": ..., "repr": ...} representation for
bytes, which is exactly the shape tools/import_diagnostics.py's
parse_legacy_value already reads back.

Adds a regression test covering both builder arguments.
---
 tests/common.py        |  5 ++-
 tests/test_discover.py | 80 ++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 84 insertions(+), 1 deletion(-)

diff --git a/tests/common.py b/tests/common.py
index 5cbac97e1..e5b1e1c54 100644
--- a/tests/common.py
+++ b/tests/common.py
@@ -639,11 +639,14 @@ def create_mock_zigpy_device(
 
 
 class ZhaJsonEncoder(json.JSONEncoder):
-    """JSON encoder to handle common Python data types, currently just `set`."""
+    """JSON encoder to handle common Python data types, e.g. `set` and `bytes`."""
 
     def default(self, obj):
         """Convert non-JSON types."""
         if isinstance(obj, set):
             return sorted(obj, key=repr)
 
+        if isinstance(obj, bytes):
+            return {"__type": str(type(obj)), "repr": repr(obj)}
+
         return super().default(obj)
diff --git a/tests/test_discover.py b/tests/test_discover.py
index 3c9755729..15ee30288 100644
--- a/tests/test_discover.py
+++ b/tests/test_discover.py
@@ -21,6 +21,7 @@
     NumberMetadata,
     ZCLSensorMetadata,
 )
+from zhaquirks.clusters import CustomCluster
 from zhaquirks.ikea import PowerConfig1CRCluster, ScenesCluster
 from zhaquirks.xiaomi import (
     BasicCluster,
@@ -38,6 +39,7 @@
 import zigpy.zcl.clusters.closures
 import zigpy.zcl.clusters.general
 from zigpy.zcl.clusters.general import Ota, QueryNextImageCommand
+from zigpy.zcl.clusters.manufacturer_specific import ManufacturerSpecificCluster
 import zigpy.zcl.clusters.security
 import zigpy.zcl.foundation as zcl_f
 
@@ -931,6 +933,84 @@ async def test_get_diagnostics_json_repeated_calls(zha_gateway: Gateway) -> None
     assert first == second
 
 
+async def test_get_diagnostics_json_bytes_entity_info(zha_gateway: Gateway) -> None:
+    """Test that `bytes` in quirk entity info can be serialized."""
+
+    class FakeCluster(CustomCluster, ManufacturerSpecificCluster):
+        """Fake manufacturer cluster with an octet string attribute and command."""
+
+        cluster_id = 0xFC11
+        ep_attribute = "fake_cluster"
+
+        class AttributeDefs(zcl_f.BaseAttributeDefs):
+            """Attribute definitions."""
+
+            raw_attr = zcl_f.ZCLAttributeDef(id=0x0000, type=zigpy.types.LVBytes)
+
+        class ServerCommandDefs(zcl_f.BaseCommandDefs):
+            """Server command definitions."""
+
+            raw_command = zcl_f.ZCLCommandDef(
+                id=0x00, schema={"payload": zigpy.types.LVBytes}
+            )
+
+    registry = DeviceRegistry()
+    zigpy_device = create_mock_zigpy_device(
+        zha_gateway,
+        {
+            1: {
+                SIG_EP_INPUT: [
+                    zigpy.zcl.clusters.general.Basic.cluster_id,
+                    FakeCluster.cluster_id,
+                ],
+                SIG_EP_OUTPUT: [],
+                SIG_EP_TYPE: zigpy.profiles.zha.DeviceType.REMOTE_CONTROL,
+                SIG_EP_PROFILE: zigpy.profiles.zha.PROFILE_ID,
+            }
+        },
+        manufacturer="Fake_Manufacturer",
+        model="Fake_Model",
+        registry=registry,
+    )
+
+    (
+        QuirkBuilder("Fake_Manufacturer", "Fake_Model")
+        .replaces(FakeCluster)
+        .command_button(
+            FakeCluster.ServerCommandDefs.raw_command.name,
+            FakeCluster.cluster_id,
+            command_args=(b"\x00",),
+            translation_key="raw_command",
+            fallback_name="Raw command",
+        )
+        .write_attr_button(
+            FakeCluster.AttributeDefs.raw_attr.name,
+            b"\x00",
+            FakeCluster.cluster_id,
+            translation_key="raw_attr",
+            fallback_name="Raw attr",
+        )
+        .add_to_registry(registry)
+    )
+
+    zigpy_device = registry.resolve(zigpy_device)
+    zha_device = await join_zigpy_device(zha_gateway, zigpy_device)
+
+    # what tools/import_diagnostics.py and tools/regenerate_diagnostics.py do
+    diag = json.loads(json.dumps(zha_device.get_diagnostics_json(), cls=ZhaJsonEncoder))
+
+    buttons = diag["zha_lib_entities"][Platform.BUTTON]
+    expected = {"__type": "<class 'bytes'>", "repr": "b'\\x00'"}
+
+    args = next(e["args"] for e in buttons if "args" in e)
+    assert args == [expected]
+
+    attribute_value = next(
+        e["attribute_value"] for e in buttons if "attribute_value" in e
+    )
+    assert attribute_value == expected
+
+
 async def test_diagnostics_includes_ota_last_query_cmd(zha_gateway: Gateway) -> None:
     """Test that diagnostics includes last_query_cmd for OTA clusters."""
     zigpy_device = await zigpy_device_from_json(