From 693bc4f7ed38795099921254ccd121a20723add2 Mon Sep 17 00:00:00 2001
From: "Teemu R." <tpr@iki.fi>
Date: Wed, 4 Nov 2026 19:09:38 +0100
Subject: [PATCH] Use clearer error message for unsupported encryption types
 (#1831)

Devices that announce an encryption type the library does not know, such
as `TPAP` used by newer Tapo devices (e.g. RV20 Max Plus), previously
failed with a generic message that dumped the whole encryption scheme:

```
Unsupported device 192.168.xx.xx of type SMART.TAPOROBOVAC with encrypt_scheme EncryptionScheme(is_support_https=True, encrypt_type='TPAP', http_port=4433, lv=2)
```

This can be rather confusing to interpret, as it does not tell what is
not supported (e.g., the device type is definitely supported on non-tpap
transports).
This PR adds a separate check and error message for cases where the
encryption type is not supported, giving this error:
```
Device 192.168.xx.xx (SMART.TAPOROBOVAC) uses unsupported encryption type TPAP
```
---
 kasa/discover.py        |  8 ++++++++
 tests/test_discovery.py | 27 +++++++++++++++++++++++++++
 2 files changed, 35 insertions(+)

diff --git a/kasa/discover.py b/kasa/discover.py
index fa95618c..b958e76f 100755
--- a/kasa/discover.py
+++ b/kasa/discover.py
@@ -845,6 +845,14 @@ class Discover:
                 discovery_result=discovery_result.to_dict(),
                 host=discovery_result.ip,
             )
+
+        if encrypt_type not in {e.value for e in DeviceEncryptionType}:
+            raise UnsupportedDeviceError(
+                f"Device {discovery_result.ip} ({type_}) uses unsupported "
+                f"encryption type {encrypt_type}",
+                discovery_result=discovery_result.to_dict(),
+                host=discovery_result.ip,
+            )
         return DeviceConnectionParameters.from_values(
             type_,
             encrypt_type,
diff --git a/tests/test_discovery.py b/tests/test_discovery.py
index 7248c124..7f30a0a4 100644
--- a/tests/test_discovery.py
+++ b/tests/test_discovery.py
@@ -798,3 +798,30 @@ async def test_connection_parameters_from_encrypt_type_list_only():
     result["encrypt_type"] = ["9"]
     with pytest.raises(UnsupportedDeviceError, match="no encryption type"):
         Discover._get_connection_parameters(DiscoveryResult.from_dict(result))
+
+
+async def test_connection_parameters_unsupported_encrypt_type():
+    """An unknown encrypt_type is named in the error."""
+    result = {
+        "device_type": "SMART.TAPOROBOVAC",
+        "device_model": "RV20 Max Plus(EU)",
+        "device_id": "0000000000000000000000000000000000000000",
+        "ip": "127.0.0.123",
+        "mac": "B0-19-21-00-00-00",
+        "mgt_encrypt_schm": {
+            "is_support_https": True,
+            "http_port": 4433,
+            "encrypt_type": "TPAP",
+            "lv": 2,
+        },
+    }
+    with pytest.raises(
+        UnsupportedDeviceError,
+        match=(
+            r"^Device 127\.0\.0\.123 \(SMART\.TAPOROBOVAC\) uses unsupported "
+            r"encryption type TPAP$"
+        ),
+    ) as exc_info:
+        Discover._get_connection_parameters(DiscoveryResult.from_dict(result))
+    assert exc_info.value.host == "127.0.0.123"
+    assert exc_info.value.discovery_result