Improve mac_address_from_name() function to avoid double discovery of Shelly devices (home-assistant#153343)

Author: bieniu

homeassistant/components/shelly/utils.py

@@ -552,8 +552,15 @@ def percentage_to_brightness(percentage: int) -> int:
 
 def mac_address_from_name(name: str) -> str | None:
     """Convert a name to a mac address."""
-    mac = name.partition(".")[0].partition("-")[-1]
-    return mac.upper() if len(mac) == 12 else None
+    base = name.split(".", 1)[0]
+    if "-" not in base:
+        return None
+
+    mac = base.rsplit("-", 1)[-1]
+    if len(mac) != 12 or not all(char in "0123456789abcdefABCDEF" for char in mac):
+        return None
+
+    return mac.upper()
 
 
 def get_release_url(gen: int, model: str, beta: bool) -> str | None:

tests/components/shelly/test_utils.py

@@ -34,6 +34,7 @@
     get_rpc_channel_name,
     get_rpc_input_triggers,
     is_block_momentary_input,
+    mac_address_from_name,
 )
 from homeassistant.util import dt as dt_util
 
@@ -327,3 +328,17 @@ def test_get_release_url(
 def test_get_host(host: str, expected: str) -> None:
     """Test get_host function."""
     assert get_host(host) == expected
+
+
+@pytest.mark.parametrize(
+    ("name", "result"),
+    [
+        ("shelly1pm-AABBCCDDEEFF", "AABBCCDDEEFF"),
+        ("Shelly Plus 1 [DDEEFF]", None),
+        ("S11-Schlafzimmer", None),
+        ("22-Kueche-links", None),
+    ],
+)
+def test_mac_address_from_name(name: str, result: str | None) -> None:
+    """Test mac_address_from_name() function."""
+    assert mac_address_from_name(name) == result