pb-service: get a Bluetooth hub's name from bleak, not its GATT

packages/pb-service/CHANGELOG.md

@@ -5,6 +5,10 @@ Notable changes to `pybricks-service`. The format is based on
 
 ## [Unreleased]
 
+### Fixed
+
+- Connecting over Bluetooth on macOS, which failed reading the hub's name.
+
 ## [1.0.0b1] - 2026-10-18
 
 ### Added

packages/pb-service/src/pb_service/hub/ble.py

@@ -115,6 +115,11 @@ def __init__(self, client: BleakClient) -> None:
     async def read_characteristic(self, uuid: str) -> bytes:
         return bytes(await self._client.read_gatt_char(uuid))
 
+    async def read_name(self) -> str:
+        # Not a read of the Device Name characteristic, which macOS does not
+        # allow. bleak asks the OS for the name instead, on every platform.
+        return self._client.name
+
     async def write_characteristic(
         self, uuid: str, data: bytes, *, response: bool = True
     ) -> None:

packages/pb-service/src/pb_service/hub/connection.py

@@ -210,9 +210,7 @@ async def _run(self, *, task_status: TaskStatus[HubInfo]) -> None:
 
     async def _handshake(self, link: HubLink) -> HubInfo:
         """Read the hub's identity and capabilities."""
-        name = (await link.read_characteristic(p.DEVICE_NAME_UUID)).decode(
-            "utf-8", "replace"
-        )
+        name = await link.read_name()
         firmware = (await link.read_characteristic(p.FIRMWARE_REVISION_UUID)).decode(
             "utf-8", "replace"
         )

packages/pb-service/src/pb_service/hub/fake.py

@@ -295,8 +295,8 @@ def read(self, uuid: str) -> bytes:
             HubRejection: If this hub has no such characteristic.
         """
 
-        if uuid == p.DEVICE_NAME_UUID:
-            return self.name.encode()
+        # No Device Name, as on macOS, where CoreBluetooth keeps the Generic
+        # Access service to itself: the name has to come from elsewhere.
 
         if uuid == p.FIRMWARE_REVISION_UUID:
             return self.firmware.encode()
@@ -341,6 +341,10 @@ async def read_characteristic(self, uuid: str) -> bytes:
         self._require_connected()
         return self._hub.read(uuid)
 
+    async def read_name(self) -> str:
+        self._require_connected()
+        return self._hub.name
+
     async def write_characteristic(
         self, uuid: str, data: bytes, *, response: bool = True
     ) -> None:

packages/pb-service/src/pb_service/hub/stream/link.py

@@ -89,6 +89,11 @@ async def read_characteristic(self, uuid: str) -> bytes:
                     if reply is not None and reply[0] == selector:
                         return reply[1]
 
+    async def read_name(self) -> str:
+        return (await self.read_characteristic(p.DEVICE_NAME_UUID)).decode(
+            "utf-8", "replace"
+        )
+
     async def write_characteristic(
         self, uuid: str, data: bytes, *, response: bool = True
     ) -> None:

packages/pb-service/src/pb_service/hub/transport.py

@@ -266,6 +266,17 @@ async def read_characteristic(self, uuid: str) -> bytes:
         """
         ...
 
+    async def read_name(self) -> str:
+        """Read the hub's name.
+
+        Not a characteristic read on every transport: some operating systems
+        keep the GATT Device Name characteristic to themselves.
+
+        Returns:
+            What the hub is called.
+        """
+        ...
+
     async def write_characteristic(
         self, uuid: str, data: bytes, *, response: bool = True
     ) -> None:

packages/pb-service/src/pb_service/hub/usb/transport.py

@@ -215,9 +215,7 @@ async def _probe(
                     async with anyio.create_task_group() as tg:
                         tg.start_soon(link.run, None)
 
-                        name = (
-                            await link.read_characteristic(p.DEVICE_NAME_UUID)
-                        ).decode("utf-8", "replace")
+                        name = await link.read_name()
                         raw_pnp = await link.read_characteristic(p.PNP_ID_UUID)
 
                         tg.cancel_scope.cancel()

packages/pb-service/tests/test_combined.py

@@ -98,6 +98,9 @@ def is_connected(self) -> bool:
     async def read_characteristic(self, uuid: str) -> bytes:
         return b""
 
+    async def read_name(self) -> str:
+        return ""
+
     async def write_characteristic(
         self, uuid: str, data: bytes, *, response: bool = True
     ) -> None:

packages/pb-service/tests/test_connection.py

@@ -100,6 +100,23 @@ async def test_handshake_reads_identity_and_capabilities(hub: FakeHub) -> None:
         connection.close("done")
 
 
+async def test_handshake_names_the_hub_without_the_device_name_characteristic(
+    hub: FakeHub,
+) -> None:
+    # macOS will not let the Device Name characteristic be read, and the fake
+    # hub does not serve it either, so reading it here fails as it did there.
+    # https://github.com/pybricks/support/issues/2870
+    transport = FakeHubTransport(hub)
+
+    with pytest.raises(HubRejection):
+        hub.read(p.DEVICE_NAME_UUID)
+
+    async with anyio.create_task_group() as tg:
+        connection, info = await _start(tg, transport, hub)
+        assert info.name == hub.name
+        connection.close("done")
+
+
 async def test_old_firmware_is_refused_with_advice() -> None:
     # A hub too old for the capabilities characteristic cannot be supported,
     # and the message should say what to do about it.