fix(core): do not send ButtonRequest on every paging event

partial revert of 54db2291f2 from #1671

common/protob/messages-common.proto

@@ -47,11 +47,6 @@ message Failure {
 message ButtonRequest {
     optional ButtonRequestType code = 1;  // enum identifier of the screen
     optional uint32 pages = 2;            // if the screen is paginated, number of pages
-    optional uint32 page_number = 3;      // if the screen is paginated, current page (1-based)
-    /* Rationale: both fields are optional, and neither field can have 0 as a valid
-    value. So both testing `if pages` and `if page_number` do the right thing.
-    Also the following is always true: `page_is_last = (page_number == pages)` */
-
     /**
     * Type of button request
     */

core/CHANGELOG.md

@@ -7,7 +7,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 ## 2.4.1 [14th July 2021]
 
 ### Added
-- ButtonRequest is sent also after every screen of a multi-page view.  [#1671]
+- ButtonRequest for multi-page views contains number of pages.  [#1671]
 
 ### Changed
 - Converted altcoin apps to common layout code.  [#1538]

core/src/trezor/messages.py

@@ -283,14 +283,12 @@ if TYPE_CHECKING:
     class ButtonRequest(protobuf.MessageType):
         code: ButtonRequestType | None
         pages: int | None
-        page_number: int | None
 
         def __init__(
             self,
             *,
             code: ButtonRequestType | None = None,
             pages: int | None = None,
-            page_number: int | None = None,
         ) -> None:
             pass
 

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

@@ -111,12 +111,9 @@ class Paginated(ui.Layout):
         code: ButtonRequestType = ButtonRequestType.Other,
     ) -> Any:
         workflow.close_others()
+        await ctx.call(ButtonRequest(code=code, pages=len(self.pages)), ButtonAck)
         result = WAS_PAGED
         while result is WAS_PAGED:
-            br = ButtonRequest(
-                code=code, pages=len(self.pages), page_number=self.page + 1
-            )
-            await ctx.call(br, ButtonAck)
             result = await self
 
         return result

python/src/trezorlib/messages.py

@@ -701,7 +701,6 @@ class ButtonRequest(protobuf.MessageType):
     FIELDS = {
         1: protobuf.Field("code", ButtonRequestType, repeated=False, required=False),
         2: protobuf.Field("pages", "uint32", repeated=False, required=False),
-        3: protobuf.Field("page_number", "uint32", repeated=False, required=False),
     }
 
     def __init__(
@@ -709,11 +708,9 @@ class ButtonRequest(protobuf.MessageType):
         *,
         code: Optional[ButtonRequestType] = None,
         pages: Optional[int] = None,
-        page_number: Optional[int] = None,
     ) -> None:
         self.code = code
         self.pages = pages
-        self.page_number = page_number
 
 
 class ButtonAck(protobuf.MessageType):