From 4a5a09a0e928a4ce9780940c71e3aae5abd1f674 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@koston.org>
Date: Tue, 21 Jul 2020 14:29:57 -1000
Subject: [PATCH] Speed up group setup (#38048)

---
 homeassistant/components/group/__init__.py | 10 +++++++++-
 tests/components/group/test_init.py        | 22 ++++++++++++++++++++++
 2 files changed, 31 insertions(+), 1 deletion(-)

diff --git a/homeassistant/components/group/__init__.py b/homeassistant/components/group/__init__.py
index 5a2c11dc481..11c78a9b271 100644
--- a/homeassistant/components/group/__init__.py
+++ b/homeassistant/components/group/__init__.py
@@ -39,6 +39,7 @@ from homeassistant.loader import bind_hass
 # mypy: allow-untyped-calls, allow-untyped-defs, no-check-untyped-defs
 
 DOMAIN = "group"
+GROUP_ORDER = "group_order"
 
 ENTITY_ID_FORMAT = DOMAIN + ".{}"
 
@@ -407,16 +408,23 @@ class Group(Entity):
 
         This method must be run in the event loop.
         """
+        hass.data.setdefault(GROUP_ORDER, 0)
+
         group = Group(
             hass,
             name,
-            order=len(hass.states.async_entity_ids(DOMAIN)),
+            order=hass.data[GROUP_ORDER],
             icon=icon,
             user_defined=user_defined,
             entity_ids=entity_ids,
             mode=mode,
         )
 
+        # Keep track of the group order without iterating
+        # every state in the state machine every time
+        # we setup a new group
+        hass.data[GROUP_ORDER] += 1
+
         group.entity_id = async_generate_entity_id(
             ENTITY_ID_FORMAT, object_id or name, hass=hass
         )
diff --git a/tests/components/group/test_init.py b/tests/components/group/test_init.py
index 921b810fe39..3709c4856a2 100644
--- a/tests/components/group/test_init.py
+++ b/tests/components/group/test_init.py
@@ -490,3 +490,25 @@ async def test_service_group_set_group_remove_group(hass):
 
     group_state = hass.states.get("group.user_test_group")
     assert group_state is None
+
+
+async def test_group_order(hass):
+    """Test that order gets incremented when creating a new group."""
+    hass.states.async_set("light.bowl", STATE_ON)
+
+    assert await async_setup_component(
+        hass,
+        "group",
+        {
+            "group": {
+                "group_zero": {"entities": "light.Bowl", "icon": "mdi:work"},
+                "group_one": {"entities": "light.Bowl", "icon": "mdi:work"},
+                "group_two": {"entities": "light.Bowl", "icon": "mdi:work"},
+            }
+        },
+    )
+    await hass.async_block_till_done()
+
+    assert hass.states.get("group.group_zero").attributes["order"] == 0
+    assert hass.states.get("group.group_one").attributes["order"] == 1
+    assert hass.states.get("group.group_two").attributes["order"] == 2