fix(python): bring back firmware version check

python/src/trezorlib/cli/trezorctl.py

@@ -324,8 +324,6 @@ def version() -> str:
 @with_session(empty_passphrase=True)
 def ping(session: "Session", message: str, button_protection: bool) -> str:
     """Send ping message."""
-
-    # TODO return short-circuit from old client for old Trezors
     return session.ping(message, button_protection)
 
 

python/src/trezorlib/client.py

@@ -18,6 +18,7 @@ from __future__ import annotations
 import logging
 import os
 import typing as t
+import warnings
 from enum import IntEnum
 
 from . import exceptions, mapping, messages, models
@@ -62,7 +63,7 @@ class TrezorClient:
     _seedless_session: Session | None = None
     _features: messages.Features | None = None
     _protocol_version: int
-    _setup_pin: str | None = None  # Should by used only by conftest
+    _setup_pin: str | None = None  # Should be used only by conftest
 
     def __init__(
         self,
@@ -170,6 +171,7 @@ class TrezorClient:
     def features(self) -> messages.Features:
         if self._features is None:
             self._features = self.protocol.get_features()
+            self.check_firmware_version(warn_only=True)
         assert self._features is not None
         return self._features
 
@@ -203,12 +205,25 @@ class TrezorClient:
     def refresh_features(self) -> messages.Features:
         self.protocol.update_features()
         self._features = self.protocol.get_features()
+        self.check_firmware_version(warn_only=True)
         return self._features
 
     def _get_protocol(self) -> Channel:
         protocol = ProtocolV1Channel(self.transport, mapping.DEFAULT_MAPPING)
         return protocol
 
+    def is_outdated(self) -> bool:
+        if self.features.bootloader_mode:
+            return False
+        return self.version < self.model.minimum_version
+
+    def check_firmware_version(self, warn_only: bool = False) -> None:
+        if self.is_outdated():
+            if warn_only:
+                warnings.warn("Firmware is out of date", stacklevel=2)
+            else:
+                raise exceptions.OutdatedFirmwareError(OUTDATED_FIRMWARE_ERROR)
+
 
 def get_default_client(
     path: t.Optional[str] = None,

python/src/trezorlib/transport/session.py

@@ -66,6 +66,22 @@ class Session:
         self._write(messages.Cancel())
 
     def ping(self, message: str, button_protection: bool | None = None) -> str:
+        # We would like ping to work on any valid TrezorClient instance, but
+        # due to the protection modes, we need to go through self.call, and that will
+        # raise an exception if the firmware is too old.
+        # So we short-circuit the simplest variant of ping with call_raw.
+        if not button_protection:
+            resp = self.call_raw(messages.Ping(message=message))
+            if isinstance(resp, messages.ButtonRequest):
+                # device is PIN-locked.
+                # respond and hope for the best
+                resp = (self.client.button_callback or default_button_callback)(
+                    self, resp
+                )
+            resp = messages.Success.ensure_isinstance(resp)
+            assert resp.message is not None
+            return resp.message
+
         resp = self.call(
             messages.Ping(message=message, button_protection=button_protection),
             expect=messages.Success,