refactor(core): get_context raises NoWireContext if not found

[no changelog]

core/src/apps/management/ble/unpair.py

@@ -10,16 +10,20 @@ if TYPE_CHECKING:
 async def unpair(msg: BleUnpair) -> None:
     from trezor.messages import Success
     from trezor.ui.layouts import confirm_action
-    from trezor.wire.context import get_context
+    from trezor.wire.context import NoWireContext, get_context
 
     if msg.all:
         await confirm_action("erase bonds", TR.ble__unpair_title, TR.ble__unpair_all)
     else:
         await confirm_action("unpair", TR.ble__unpair_title, TR.ble__unpair_current)
 
-    ctx = get_context()
-
-    await ctx.write(Success(message="Erasing.."))
+    # NOTE: refactor into ctx.maybe_write if we end up doing this in multiple places
+    try:
+        ctx = get_context()
+    except NoWireContext:
+        pass
+    else:
+        await ctx.write(Success(message="Erasing..."))
 
     if msg.all:
         ble.erase_bonds()

core/src/trezor/wire/context.py

@@ -47,6 +47,10 @@ class UnexpectedMessageException(Exception):
         self.msg = msg
 
 
+class NoWireContext(RuntimeError):
+    pass
+
+
 CURRENT_CONTEXT: Context | None = None
 
 
@@ -58,7 +62,7 @@ async def call(
 
     Raises if there is no context for this workflow."""
     if CURRENT_CONTEXT is None:
-        raise RuntimeError("No wire context")
+        raise NoWireContext
 
     return await CURRENT_CONTEXT.call(msg, expected_type)
 
@@ -72,7 +76,7 @@ async def call_any(
 
     Raises if there is no context for this workflow."""
     if CURRENT_CONTEXT is None:
-        raise RuntimeError("No wire context")
+        raise NoWireContext
 
     await CURRENT_CONTEXT.write(msg)
     del msg
@@ -101,9 +105,11 @@ def get_context() -> Context:
 
     Result of this function should not be stored -- the context is technically allowed
     to change inbetween any `await` statements.
+
+    Raises KeyError if there is currently no context.
     """
     if CURRENT_CONTEXT is None:
-        raise RuntimeError("No wire context")
+        raise NoWireContext
     return CURRENT_CONTEXT