refactor(core): limit global imports in key places

so that by importing `apps.base`, we don't pull in the whole circus

core/src/apps/base.py

@@ -1,22 +1,15 @@
-import storage
+import storage.cache
 import storage.device
-import storage.recovery
+from trezor import config, utils, wire, workflow
-import storage.sd_salt
+from trezor.messages import MessageType
-from storage import cache
-from trezor import config, sdcard, ui, utils, wire, workflow
-from trezor.messages import Capability, MessageType
-from trezor.messages.Features import Features
-from trezor.messages.PreauthorizedRequest import PreauthorizedRequest
 from trezor.messages.Success import Success
 
-from apps.common import mnemonic, safety_checks
-from apps.common.request_pin import verify_user_pin
-
 from . import workflow_handlers
 
 if False:
     import protobuf
     from typing import Iterable, NoReturn, Protocol
+    from trezor.messages.Features import Features
     from trezor.messages.Initialize import Initialize
     from trezor.messages.EndSession import EndSession
     from trezor.messages.GetFeatures import GetFeatures
@@ -37,6 +30,15 @@ if False:
 
 
 def get_features() -> Features:
+    import storage.recovery
+    import storage.sd_salt
+
+    from trezor import sdcard
+    from trezor.messages import Capability
+    from trezor.messages.Features import Features
+
+    from apps.common import mnemonic, safety_checks
+
     f = Features(
         vendor="trezor.io",
         language="en-US",
@@ -107,7 +109,7 @@ async def handle_Initialize(ctx: wire.Context, msg: Initialize) -> Features:
     features = get_features()
     if msg.session_id:
         msg.session_id = bytes(msg.session_id)
-    features.session_id = cache.start_session(msg.session_id)
+    features.session_id = storage.cache.start_session(msg.session_id)
     return features
 
 
@@ -125,7 +127,7 @@ async def handle_LockDevice(ctx: wire.Context, msg: LockDevice) -> Success:
 
 
 async def handle_EndSession(ctx: wire.Context, msg: EndSession) -> Success:
-    cache.end_current_session()
+    storage.cache.end_current_session()
     return Success()
 
 
@@ -141,6 +143,8 @@ async def handle_Ping(ctx: wire.Context, msg: Ping) -> Success:
 async def handle_DoPreauthorized(
     ctx: wire.Context, msg: DoPreauthorized
 ) -> protobuf.MessageType:
+    from trezor.messages.PreauthorizedRequest import PreauthorizedRequest
+
     authorization: Authorization = storage.cache.get(
         storage.cache.APP_BASE_AUTHORIZATION
     )
@@ -194,6 +198,8 @@ ALLOW_WHILE_LOCKED = (
 
 
 def set_homescreen() -> None:
+    import storage.recovery
+
     if not config.is_unlocked():
         from apps.homescreen.lockscreen import lockscreen
 
@@ -229,6 +235,8 @@ async def unlock_device(ctx: wire.GenericContext = wire.DUMMY_CONTEXT) -> None:
     If the storage is locked, attempt to unlock it. Reset the homescreen and the wire
     handler.
     """
+    from apps.common.request_pin import verify_user_pin
+
     if not config.is_unlocked():
         # verify_user_pin will raise if the PIN was invalid
         await verify_user_pin(ctx)
@@ -264,6 +272,8 @@ def get_pinlocked_handler(
 
 # this function is also called when handling ApplySettings
 def reload_settings_from_storage() -> None:
+    from trezor import ui
+
     workflow.idle_timer.set(
         storage.device.get_autolock_delay_ms(), lock_device_if_unlocked
     )

core/src/apps/common/mnemonic.py

@@ -1,8 +1,6 @@
 import storage.device
 from trezor import ui, utils, workflow
-from trezor.crypto import bip39, slip39
 from trezor.messages import BackupType
-from trezor.ui.components.tt.text import Text
 
 if False:
     from trezor.messages.ResetDevice import EnumTypeBackupType
@@ -39,9 +37,13 @@ def get_seed(passphrase: str = "", progress_bar: bool = True) -> bytes:
         render_func = _render_progress
 
     if is_bip39():
+        from trezor.crypto import bip39
+
         seed = bip39.seed(mnemonic_secret.decode(), passphrase, render_func)
 
     else:  # SLIP-39
+        from trezor.crypto import slip39
+
         identifier = storage.device.get_slip39_identifier()
         iteration_exponent = storage.device.get_slip39_iteration_exponent()
         if identifier is None or iteration_exponent is None:
@@ -55,6 +57,8 @@ def get_seed(passphrase: str = "", progress_bar: bool = True) -> bytes:
 
 
 def _start_progress() -> None:
+    from trezor.ui.components.tt.text import Text
+
     # Because we are drawing to the screen manually, without a layout, we
     # should make sure that no other layout is running.
     workflow.close_others()

core/src/apps/common/passphrase.py

@@ -3,10 +3,7 @@ from micropython import const
 import storage.device
 from trezor import wire, workflow
 from trezor.messages import ButtonRequestType
-from trezor.messages.PassphraseAck import PassphraseAck
-from trezor.messages.PassphraseRequest import PassphraseRequest
 from trezor.ui import ICON_CONFIG, draw_simple
-from trezor.ui.components.tt.passphrase import CANCELLED, PassphraseKeyboard
 from trezor.ui.components.tt.text import Text
 
 from . import button_request
@@ -41,6 +38,9 @@ async def _request_from_user(ctx: wire.Context) -> str:
 
 
 async def _request_on_host(ctx: wire.Context) -> str:
+    from trezor.messages.PassphraseAck import PassphraseAck
+    from trezor.messages.PassphraseRequest import PassphraseRequest
+
     _entry_dialog()
 
     request = PassphraseRequest()
@@ -74,6 +74,8 @@ async def _request_on_host(ctx: wire.Context) -> str:
 
 
 async def _request_on_device(ctx: wire.Context) -> str:
+    from trezor.ui.components.tt.passphrase import CANCELLED, PassphraseKeyboard
+
     await button_request(ctx, code=ButtonRequestType.PassphraseEntry)
 
     keyboard = PassphraseKeyboard("Enter passphrase", _MAX_PASSPHRASE_LEN)

core/src/apps/debug/__init__.py

@@ -4,17 +4,19 @@ if not __debug__:
     halt("debug mode inactive")
 
 if __debug__:
-    from trezor import io, ui, wire
+    from trezor import config, log, loop, utils, wire
-    from trezor.messages import MessageType, DebugSwipeDirection
+    from trezor.ui import display
+    from trezor.messages import MessageType
     from trezor.messages.DebugLinkLayout import DebugLinkLayout
-    from trezor import config, crypto, log, loop, utils
     from trezor.messages.Success import Success
 
     from apps import workflow_handlers
 
     if False:
+        from trezor.ui import Layout
         from trezor.messages.DebugLinkDecision import DebugLinkDecision
         from trezor.messages.DebugLinkGetState import DebugLinkGetState
+        from trezor.messages.DebugLinkLayout import DebugLinkLayout
         from trezor.messages.DebugLinkRecordScreen import DebugLinkRecordScreen
         from trezor.messages.DebugLinkReseedRandom import DebugLinkReseedRandom
         from trezor.messages.DebugLinkState import DebugLinkState
@@ -43,36 +45,41 @@ if __debug__:
 
     def screenshot() -> bool:
         if save_screen:
-            ui.display.save(save_screen_directory + "/refresh-")
+            display.save(save_screen_directory + "/refresh-")
             return True
         return False
 
-    def notify_layout_change(layout: ui.Layout) -> None:
+    def notify_layout_change(layout: Layout) -> None:
         global current_content
         current_content = layout.read_content()
         if watch_layout_changes:
             layout_change_chan.publish(current_content)
 
-    async def debuglink_decision_dispatcher() -> None:
+    async def dispatch_debuglink_decision(msg: DebugLinkDecision) -> None:
+        from trezor.messages import DebugSwipeDirection
+        from trezor.ui import Result
         from trezor.ui.components.tt import confirm, swipe
 
+        if msg.yes_no is not None:
+            await confirm_chan.put(
+                Result(confirm.CONFIRMED if msg.yes_no else confirm.CANCELLED)
+            )
+        if msg.swipe is not None:
+            if msg.swipe == DebugSwipeDirection.UP:
+                await swipe_chan.put(swipe.SWIPE_UP)
+            elif msg.swipe == DebugSwipeDirection.DOWN:
+                await swipe_chan.put(swipe.SWIPE_DOWN)
+            elif msg.swipe == DebugSwipeDirection.LEFT:
+                await swipe_chan.put(swipe.SWIPE_LEFT)
+            elif msg.swipe == DebugSwipeDirection.RIGHT:
+                await swipe_chan.put(swipe.SWIPE_RIGHT)
+        if msg.input is not None:
+            await input_chan.put(Result(msg.input))
+
+    async def debuglink_decision_dispatcher() -> None:
         while True:
             msg = await debuglink_decision_chan.take()
-            if msg.yes_no is not None:
+            await dispatch_debuglink_decision(msg)
-                await confirm_chan.put(
-                    ui.Result(confirm.CONFIRMED if msg.yes_no else confirm.CANCELLED)
-                )
-            if msg.swipe is not None:
-                if msg.swipe == DebugSwipeDirection.UP:
-                    await swipe_chan.put(swipe.SWIPE_UP)
-                elif msg.swipe == DebugSwipeDirection.DOWN:
-                    await swipe_chan.put(swipe.SWIPE_DOWN)
-                elif msg.swipe == DebugSwipeDirection.LEFT:
-                    await swipe_chan.put(swipe.SWIPE_LEFT)
-                elif msg.swipe == DebugSwipeDirection.RIGHT:
-                    await swipe_chan.put(swipe.SWIPE_RIGHT)
-            if msg.input is not None:
-                await input_chan.put(ui.Result(msg.input))
 
     loop.schedule(debuglink_decision_dispatcher())
 
@@ -81,6 +88,8 @@ if __debug__:
         await ctx.write(DebugLinkLayout(lines=content))
 
     async def touch_hold(x: int, y: int, duration_ms: int) -> None:
+        from trezor import io
+
         await loop.sleep(duration_ms)
         loop.synthetic_events.append((io.TOUCH, (io.TOUCH_END, x, y)))
 
@@ -96,6 +105,8 @@ if __debug__:
     async def dispatch_DebugLinkDecision(
         ctx: wire.Context, msg: DebugLinkDecision
     ) -> None:
+        from trezor import io
+
         if debuglink_decision_chan.putters:
             log.warning(__name__, "DebugLinkDecision queue is not empty")
 
@@ -149,7 +160,7 @@ if __debug__:
             save_screen = True
         else:
             save_screen = False
-            ui.display.clear_save()  # clear C buffers
+            display.clear_save()  # clear C buffers
 
         return Success()
 
@@ -157,12 +168,16 @@ if __debug__:
         ctx: wire.Context, msg: DebugLinkReseedRandom
     ) -> Success:
         if msg.value is not None:
-            crypto.random.reseed(msg.value)
+            from trezor.crypto import random
+
+            random.reseed(msg.value)
         return Success()
 
     async def dispatch_DebugLinkEraseSdCard(
         ctx: wire.Context, msg: DebugLinkEraseSdCard
     ) -> Success:
+        from trezor import io
+
         try:
             io.sdcard.power_on()
             if msg.format:

core/src/storage/cache.py

@@ -1,7 +1,7 @@
 import gc
+from trezorcrypto import random  # avoid pulling in trezor.crypto
 
 from trezor import utils
-from trezor.crypto import random
 
 if False:
     from typing import Sequence

core/src/storage/device.py

@@ -2,8 +2,6 @@ from micropython import const
 from ubinascii import hexlify
 
 from storage import common
-from trezor.crypto import random
-from trezor.messages import BackupType
 
 if False:
     from trezor.messages.ResetDevice import EnumTypeBackupType
@@ -37,8 +35,6 @@ INITIALIZED                = const(0x13)  # bool (0x01 or empty)
 _SAFETY_CHECK_LEVEL        = const(0x14)  # int
 _EXPERIMENTAL_FEATURES     = const(0x15)  # bool (0x01 or empty)
 
-_DEFAULT_BACKUP_TYPE       = BackupType.Bip39
-
 SAFETY_CHECK_LEVEL_STRICT  : Literal[0] = const(0)
 SAFETY_CHECK_LEVEL_PROMPT  : Literal[1] = const(1)
 _DEFAULT_SAFETY_CHECK_LEVEL = SAFETY_CHECK_LEVEL_STRICT
@@ -79,6 +75,8 @@ def is_initialized() -> bool:
 
 
 def _new_device_id() -> str:
+    from trezorcrypto import random  # avoid pulling in trezor.crypto
+
     return hexlify(random.bytes(12)).decode().upper()
 
 
@@ -121,9 +119,11 @@ def get_mnemonic_secret() -> bytes | None:
 
 
 def get_backup_type() -> EnumTypeBackupType:
+    from trezor.messages import BackupType
+
     backup_type = common.get_uint8(_NAMESPACE, _BACKUP_TYPE)
     if backup_type is None:
-        backup_type = _DEFAULT_BACKUP_TYPE
+        backup_type = BackupType.Bip39
 
     if backup_type not in (
         BackupType.Bip39,

core/src/storage/recovery.py

@@ -1,7 +1,6 @@
 from micropython import const
 
-from storage import common, recovery_shares
+from storage import common
-from trezor.crypto import slip39
 
 # Namespace:
 _NAMESPACE = common.APP_RECOVERY
@@ -86,22 +85,26 @@ def set_slip39_remaining_shares(shares_remaining: int, group_index: int) -> None
     0x10 (16) was chosen as the default value because it's the max
     share count for a group.
     """
+    from trezor.crypto.slip39 import MAX_SHARE_COUNT
+
     _require_progress()
     remaining = common.get(_NAMESPACE, _REMAINING)
     group_count = get_slip39_group_count()
     if not group_count:
         raise RuntimeError
     if remaining is None:
-        remaining = bytearray([slip39.MAX_SHARE_COUNT] * group_count)
+        remaining = bytearray([MAX_SHARE_COUNT] * group_count)
     remaining = bytearray(remaining)
     remaining[group_index] = shares_remaining
     common.set(_NAMESPACE, _REMAINING, remaining)
 
 
 def get_slip39_remaining_shares(group_index: int) -> int | None:
+    from trezor.crypto.slip39 import MAX_SHARE_COUNT
+
     _require_progress()
     remaining = common.get(_NAMESPACE, _REMAINING)
-    if remaining is None or remaining[group_index] == slip39.MAX_SHARE_COUNT:
+    if remaining is None or remaining[group_index] == MAX_SHARE_COUNT:
         return None
     else:
         return remaining[group_index]
@@ -120,6 +123,8 @@ def fetch_slip39_remaining_shares() -> list[int] | None:
 
 
 def end_progress() -> None:
+    from . import recovery_shares
+
     _require_progress()
     common.delete(_NAMESPACE, _IN_PROGRESS)
     common.delete(_NAMESPACE, _DRY_RUN)

core/src/trezor/pin.py

@@ -1,4 +1,4 @@
-from trezor import ui, utils
+from trezor import utils
 
 if False:
     from typing import Any
@@ -10,6 +10,8 @@ keepalive_callback: Any = None
 
 
 def show_pin_timeout(seconds: int, progress: int, message: str) -> bool:
+    from trezor import ui
+
     global _previous_progress
     global _previous_seconds
 

core/src/trezor/ui/__init__.py

@@ -5,9 +5,6 @@ from trezorui import Display
 
 from trezor import io, loop, res, utils, workflow
 
-if __debug__:
-    from apps.debug import notify_layout_change
-
 if False:
     from typing import Any, Awaitable, Generator, TypeVar
 
@@ -37,9 +34,10 @@ _alert_in_progress = False
 
 # in debug mode, display an indicator in top right corner
 if __debug__:
-    from apps.debug import screenshot
 
     def refresh() -> None:
+        from apps.debug import screenshot
+
         if not screenshot():
             display.bar(Display.WIDTH - 8, 0, 8, 8, 0xF800)
         display.refresh()
@@ -376,6 +374,8 @@ class Layout(Component):
         self.dispatch(RENDER, 0, 0)
 
         if __debug__ and self.should_notify_layout_change:
+            from apps.debug import notify_layout_change
+
             # notify about change and do not notify again until next await.
             # (handle_rendering might be called multiple times in a single await,
             # because of the endless loop in __iter__)

core/src/trezor/ui/components/common/confirm.py

@@ -1,8 +1,5 @@
 from trezor import loop, ui, wire
 
-if __debug__:
-    from apps.debug import confirm_signal
-
 if False:
     from typing import Any, Awaitable
 
@@ -52,4 +49,6 @@ class ConfirmBase(ui.Layout):
             return self.content.read_content()
 
         def create_tasks(self) -> tuple[loop.Task, ...]:
+            from apps.debug import confirm_signal
+
             return super().create_tasks() + (confirm_signal(),)

core/src/trezor/ui/components/tt/confirm.py

@@ -6,9 +6,6 @@ from trezor.ui.loader import Loader, LoaderDefault
 from ..common.confirm import CANCELLED, CONFIRMED, INFO, ConfirmBase
 from .button import Button, ButtonAbort, ButtonCancel, ButtonConfirm, ButtonDefault
 
-if __debug__:
-    from apps.debug import swipe_signal, confirm_signal
-
 if False:
     from typing import Any
     from .button import ButtonContent, ButtonStyleType
@@ -96,6 +93,8 @@ class ConfirmPageable(Confirm):
             directions = SWIPE_HORIZONTAL
 
         if __debug__:
+            from apps.debug import swipe_signal
+
             swipe = await loop.race(Swipe(directions), swipe_signal())
         else:
             swipe = await Swipe(directions)
@@ -196,6 +195,8 @@ class InfoConfirm(ui.Layout):
             return self.content.read_content()
 
         def create_tasks(self) -> tuple[loop.Task, ...]:
+            from apps.debug import confirm_signal
+
             return super().create_tasks() + (confirm_signal(),)
 
 
@@ -273,4 +274,6 @@ class HoldToConfirm(ui.Layout):
             return self.content.read_content()
 
         def create_tasks(self) -> tuple[loop.Task, ...]:
+            from apps.debug import confirm_signal
+
             return super().create_tasks() + (confirm_signal(),)

core/src/trezor/ui/components/tt/scroll.py

@@ -7,9 +7,6 @@ from .confirm import CANCELLED, CONFIRMED, Confirm
 from .swipe import SWIPE_DOWN, SWIPE_UP, SWIPE_VERTICAL, Swipe
 from .text import TEXT_MAX_LINES, Span, Text
 
-if __debug__:
-    from apps.debug import confirm_signal, swipe_signal, notify_layout_change
-
 _PAGINATED_LINE_WIDTH = const(204)
 
 
@@ -81,6 +78,8 @@ class Paginated(ui.Layout):
             directions = SWIPE_VERTICAL
 
         if __debug__:
+            from apps.debug import swipe_signal
+
             swipe = await loop.race(Swipe(directions), swipe_signal())
         else:
             swipe = await Swipe(directions)
@@ -94,6 +93,8 @@ class Paginated(ui.Layout):
         self.repaint = True
 
         if __debug__:
+            from apps.debug import notify_layout_change
+
             notify_layout_change(self)
 
         self.on_change()
@@ -110,6 +111,8 @@ class Paginated(ui.Layout):
             # shut down by a DebugLink confirm, even if used outside of a confirm() call
             # But we don't have any such usages in the codebase, and it doesn't actually
             # make much sense to use a Paginated without a way to confirm it.
+            from apps.debug import confirm_signal
+
             return tasks + (confirm_signal(),)
         else:
             return tasks
@@ -230,6 +233,8 @@ class PaginatedWithButtons(ui.Layout):
             return self.pages[self.page].read_content()
 
         def create_tasks(self) -> tuple[loop.Task, ...]:
+            from apps.debug import confirm_signal
+
             return super().create_tasks() + (confirm_signal(),)