From f3442b20b714352407e4cbfd9846606b2262430b Mon Sep 17 00:00:00 2001
From: epenet <6771947+epenet@users.noreply.github.com>
Date: Fri, 11 Sep 2026 11:26:42 +0200
Subject: [PATCH] Fix stop service in modbus (#181915)

---
 homeassistant/components/modbus/const.py    |  2 +-
 homeassistant/components/modbus/entity.py   |  6 ++-
 homeassistant/components/modbus/services.py |  2 +-
 tests/components/modbus/test_services.py    | 48 +++++++++++++++++++++
 4 files changed, 55 insertions(+), 3 deletions(-)

diff --git a/homeassistant/components/modbus/const.py b/homeassistant/components/modbus/const.py
index 18829e4cebe7..8e0c0e0c882f 100644
--- a/homeassistant/components/modbus/const.py
+++ b/homeassistant/components/modbus/const.py
@@ -155,7 +155,7 @@ SERVICE_WRITE_REGISTER = "write_register"
 SERVICE_STOP = "stop"
 
 # dispatcher signals
-SIGNAL_STOP_ENTITY = "modbus.stop"
+SIGNAL_STOP_ENTITY = "modbus.stop_{}"
 
 # integration names
 DEFAULT_HUB = "modbus_hub"
diff --git a/homeassistant/components/modbus/entity.py b/homeassistant/components/modbus/entity.py
index df7c3288230f..5e6934099a11 100644
--- a/homeassistant/components/modbus/entity.py
+++ b/homeassistant/components/modbus/entity.py
@@ -149,7 +149,11 @@ class ModbusBaseEntity(Entity):
             )
         )
         self.async_on_remove(
-            async_dispatcher_connect(self.hass, SIGNAL_STOP_ENTITY, self.async_disable)
+            async_dispatcher_connect(
+                self.hass,
+                SIGNAL_STOP_ENTITY.format(self._hub.name),
+                self.async_disable,
+            )
         )
 
 
diff --git a/homeassistant/components/modbus/services.py b/homeassistant/components/modbus/services.py
index ff49255dbdea..834707d48c8c 100644
--- a/homeassistant/components/modbus/services.py
+++ b/homeassistant/components/modbus/services.py
@@ -101,7 +101,7 @@ async def _async_stop_hub(service: ServiceCall) -> None:
     """Stop Modbus hub."""
     hass = service.hass
     hub = _get_hubs(hass)[service.data[ATTR_HUB]]
-    async_dispatcher_send(hass, SIGNAL_STOP_ENTITY)
+    async_dispatcher_send(hass, SIGNAL_STOP_ENTITY.format(hub.name))
     await hub.async_close()
 
 
diff --git a/tests/components/modbus/test_services.py b/tests/components/modbus/test_services.py
index 52a96de3e78e..14ea2ce635fb 100644
--- a/tests/components/modbus/test_services.py
+++ b/tests/components/modbus/test_services.py
@@ -28,6 +28,7 @@ from homeassistant.const import (
 )
 from homeassistant.core import HomeAssistant
 from homeassistant.exceptions import ServiceValidationError
+from homeassistant.helpers.entity_platform import async_get_platforms
 from homeassistant.setup import async_setup_component
 
 from tests.common import get_fixture_path
@@ -162,3 +163,50 @@ async def test_service_after_failed_reload_raises(
         await hass.services.async_call(DOMAIN, service, data, blocking=True)
 
     assert err.value.translation_key == "not_loaded"
+
+
+TEST_HUB_A = "hub_a"
+TEST_HUB_B = "hub_b"
+
+
+def _two_hub_config() -> dict:
+    """Return a config with two hubs, each exposing one sensor."""
+    return {
+        DOMAIN: [
+            {
+                CONF_NAME: name,
+                CONF_TYPE: "tcp",
+                CONF_HOST: "modbusHost",
+                CONF_PORT: port,
+                CONF_SENSORS: [{CONF_NAME: f"sensor_{name}", CONF_ADDRESS: 1}],
+            }
+            for name, port in ((TEST_HUB_A, 5501), (TEST_HUB_B, 5502))
+        ]
+    }
+
+
+@pytest.mark.usefixtures("mock_pymodbus")
+async def test_stop_only_disables_the_selected_hub(hass: HomeAssistant) -> None:
+    """Test stopping one hub leaves the other hub's entities alone."""
+    assert await async_setup_component(hass, DOMAIN, _two_hub_config())
+    await hass.async_block_till_done()
+
+    # async_disable only flips availability, it does not write the state, so the
+    # entity objects rather than the state machine show the effect.
+    entities = {
+        entity.entity_id: entity
+        for platform in async_get_platforms(hass, DOMAIN)
+        for entity in platform.entities.values()
+    }
+    entity_a = entities[f"sensor.sensor_{TEST_HUB_A}"]
+    entity_b = entities[f"sensor.sensor_{TEST_HUB_B}"]
+    assert entity_a.available
+    assert entity_b.available
+
+    await hass.services.async_call(
+        DOMAIN, SERVICE_STOP, {ATTR_HUB: TEST_HUB_A}, blocking=True
+    )
+    await hass.async_block_till_done()
+
+    assert not entity_a.available
+    assert entity_b.available