refactor(core): move `show_invalid_mnemonic()` into `_process_words()`
What the developer wrote
Authored by Roman Zeyde
refactor(core): move `show_invalid_mnemonic()` into `_process_words()`
In order to simplify `_DisplayHandler` interface.
[no changelog]
What changed, and why it matters
This is a small internal code cleanup in the Trezor firmware's device-recovery flow. It moves the 'invalid mnemonic' warning screen from one helper object into another function and switches the control flow from returning an awaitable to raising a custom internal exception. There is no user-visible behavior change and no security fix or vulnerability introduced.
No action required. Treat as routine refactoring.
Security signals we found
No security-relevant behavior change
Refactor only: moved existing error handling and UI call
No new trust boundaries, inputs, or outputs
No changelog entry requested by author
Evidence from the diff
The patch refactors homescreen.py in the recovery_device app. It removes show_invalid_mnemonic() from the _DisplayHandler Protocol/class and instead calls show_invalid_mnemonic(word_count) directly inside _process_words() when a MnemonicError is caught, then raises a new _RetryEntry exception to signal the caller to retry. This simplifies the _DisplayHandler interface but is functionally equivalent: the same UI is shown for the same error condition.
Changed components
core/src/apps/management/recovery_device/homescreen.pyInspect captured patch +20 / −14
diff --git a/core/src/apps/management/recovery_device/homescreen.py b/core/src/apps/management/recovery_device/homescreen.py
index ded87fd9..6038dc79 100644
--- a/core/src/apps/management/recovery_device/homescreen.py
+++ b/core/src/apps/management/recovery_device/homescreen.py
@@ -1,4 +1,4 @@
-from typing import TYPE_CHECKING, Awaitable, Protocol
+from typing import TYPE_CHECKING, Protocol
import storage.device as storage_device
import storage.recovery as storage_recovery
@@ -98,7 +98,6 @@ if TYPE_CHECKING:
async def show_state(self, is_retry: bool) -> None: ...
async def request_mnemonic(self) -> str | None: ...
- def show_invalid_mnemonic(self) -> Awaitable[None]: ...
class _DisplayHandler:
@@ -149,17 +148,11 @@ class _DisplayHandler:
await exc.show_error()
return None
- def show_invalid_mnemonic(self) -> Awaitable[None]:
- from trezor.ui.layouts.recovery import show_invalid_mnemonic
-
- return show_invalid_mnemonic(self.word_count)
-
async def _recover_secret(
recovery_type: RecoveryType, method: BackupMethod | None
) -> tuple[bytes, BackupType]:
from trezor.enums import BackupMethod
- from trezor.errors import MnemonicError
if method not in (None, BackupMethod.Display):
from trezor import log
@@ -185,8 +178,7 @@ async def _recover_secret(
if (result := await _process_words(words)) is not None:
return result
# If _process_words succeeded, at least one share was entered.
- except MnemonicError:
- await handler.show_invalid_mnemonic()
+ except _RetryEntry:
is_retry = True # Retry share entry (without showing recovery state)
@@ -313,15 +305,29 @@ async def _finish_recovery(secret: bytes, backup_type: BackupType) -> Success:
return Success(message="Device recovered")
+class _RetryEntry(Exception):
+ """Raised after entering an invalid mnemonic."""
+
+ pass
+
+
async def _process_words(words: str) -> tuple[bytes, BackupType] | None:
+ from trezor.errors import MnemonicError
+
word_count = len(words.split(" "))
is_slip39 = backup_types.is_slip39_word_count(word_count)
share = None
- if not is_slip39: # BIP-39
- secret: bytes | None = recover.process_bip39(words)
- else:
- secret, share = recover.process_slip39(words)
+ try:
+ if not is_slip39: # BIP-39
+ secret: bytes | None = recover.process_bip39(words)
+ else:
+ secret, share = recover.process_slip39(words)
+ except MnemonicError:
+ from trezor.ui.layouts.recovery import show_invalid_mnemonic
+
+ await show_invalid_mnemonic(word_count)
+ raise _RetryEntry
backup_type = backup_types.infer_backup_type(is_slip39, share)
if secret is None: # SLIP-39
Why this scored 15/100
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