python: fix behavior of client.ping() when device is locked

python/CHANGELOG.md

@@ -28,6 +28,7 @@ _At the moment, the project does **not** adhere to [Semantic Versioning](https:/
 
 - correctly calculate hashes for very small firmwares  [f#1082]
 - unified file arguments in trezorctl
+- `TrezorClient.ping()` does not crash when device is PIN-locked
 
 ## [0.12.0] - 2020-04-01
 [0.12.0]: https://github.com/trezor/trezor-firmware/compare/python/v0.11.6...python/v0.12.0

python/src/trezorlib/client.py

@@ -331,7 +331,12 @@ class TrezorClient:
             # XXX this should be: `with self:`
             try:
                 self.open()
-                return self.call_raw(messages.Ping(message=msg))
+                resp = self.call_raw(messages.Ping(message=msg))
+                if isinstance(resp, messages.ButtonRequest):
+                    # device is PIN-locked.
+                    # respond and hope for the best
+                    resp = self._callback_button(resp)
+                return resp
             finally:
                 self.close()