Note: This document covers API impact only. For more details, see the ABI compatibility page

Change an enum from flexible to strict

Overview

- init step 1 step 2 step 3
fidl link link
dart link link
go link link
hlcpp link link
llcpp link link
rust link link link

Initial State {#init}

FIDL {#fidl-init}

  1. flexible enum Color : int32 {
  2.     RED = 1;
  3.     BLUE = 2;
  4. };

Dart {#dart-init}

  1. fidllib.Color complement(fidllib.Color color) {
  2.   if (color.isUnknown()) {
  3.     return color;
  4.   }
  5.   switch (color) {
  6.     case fidllib.Color.blue:
  7.       return fidllib.Color.red;
  8.     case fidllib.Color.red:
  9.       return fidllib.Color.blue;
  10.     default:
  11.       return null;
  12.   }
  13. }

Go {#go-init}

  1. func complement(color lib.Color) lib.Color {
  2.     if color.IsUnknown() {
  3.         return color
  4.     }
  5.     switch color {
  6.     case lib.ColorBlue:
  7.         return lib.ColorRed
  8.     case lib.ColorRed:
  9.         return lib.ColorBlue
  10.     default:
  11.         return color
  12.     }
  13. }

HLCPP {#hlcpp-init}

  1. fidl_test::Color complement(fidl_test::Color color) {
  2.   if (color.IsUnknown()) {
  3.     return color;
  4.   }
  5.   switch (color) {
  6.     case fidl_test::Color::RED:
  7.       return fidl_test::Color::BLUE;
  8.     case fidl_test::Color::BLUE:
  9.       return fidl_test::Color::RED;
  10.     default:
  11.       return color;
  12.   }
  13. }

LLCPP {#llcpp-init}

  1. fidl_test::Color complement(fidl_test::Color color) {
  2.   if (color.IsUnknown()) {
  3.     return color;
  4.   }
  5.   switch (color) {
  6.     case fidl_test::Color::RED:
  7.       return fidl_test::Color::BLUE;
  8.     case fidl_test::Color::BLUE:
  9.       return fidl_test::Color::RED;
  10.     default:
  11.       return color;
  12.   }
  13. }

Rust {#rust-init}

  1. fn complement(color: &fidl_lib::Color) -> Option<fidl_lib::Color> {
  2.     match color.validate() {
  3.         Ok(fidl_lib::Color::Red) => Some(fidl_lib::Color::Blue),
  4.         Ok(fidl_lib::Color::Blue) => Some(fidl_lib::Color::Red),
  5.         _ => None,
  6.     }
  7. }

Update Source Code {#step-1}

Dart {#dart-1}

  1.   fidllib.Color complement(fidllib.Color color) {
  2. -   if (color.isUnknown()) {
  3. -     return color;
  4. -   }
  5. +   assert(color.isUnknown() == false);
  6.     switch (color) {
  7.       case fidllib.Color.blue:
  8.         return fidllib.Color.red;
  9.       case fidllib.Color.red:
  10.         return fidllib.Color.blue;
  11.       default:
  12.         return null;
  13.     }
  14.   }

Go {#go-1}

  • Remove usages of any flexible specific APIs
  1.   func complement(color lib.Color) lib.Color {
  2. -     if color.IsUnknown() {
  3. -         return color
  4. -     }
  5.       switch color {
  6.       case lib.ColorBlue:
  7.           return lib.ColorRed
  8.       case lib.ColorRed:
  9.           return lib.ColorBlue
  10.       default:
  11.           return color
  12.       }
  13.   }

HLCPP {#hlcpp-1}

  • Remove usages of any flexible specific APIs
  1.   fidl_test::Color complement(fidl_test::Color color) {
  2. -   if (color.IsUnknown()) {
  3. -     return color;
  4. -   }
  5.     switch (color) {
  6.       case fidl_test::Color::RED:
  7.         return fidl_test::Color::BLUE;
  8.       case fidl_test::Color::BLUE:
  9.         return fidl_test::Color::RED;
  10.       default:
  11.         return color;
  12.     }
  13.   }

LLCPP {#llcpp-1}

  • Remove usages of any flexible specific APIs
  1.   fidl_test::Color complement(fidl_test::Color color) {
  2. -   if (color.IsUnknown()) {
  3. -     return color;
  4. -   }
  5.     switch (color) {
  6.       case fidl_test::Color::RED:
  7.         return fidl_test::Color::BLUE;
  8.       case fidl_test::Color::BLUE:
  9.         return fidl_test::Color::RED;
  10.       default:
  11.         return color;
  12.     }
  13.   }

Rust {#rust-1}

  • Remove usages of any flexible specific APIs
  • Allow unreachable patterns and add an underscore arm to any match statements on the enum.
  1.   fn complement(color: &fidl_lib::Color) -> Option<fidl_lib::Color> {
  2. -     match color.validate() {
  3. -         Ok(fidl_lib::Color::Red) => Some(fidl_lib::Color::Blue),
  4. -         Ok(fidl_lib::Color::Blue) => Some(fidl_lib::Color::Red),
  5. +     #[allow(unreachable_patterns)]
  6. +     match color {
  7. +         fidl_lib::Color::Red => Some(fidl_lib::Color::Blue),
  8. +         fidl_lib::Color::Blue => Some(fidl_lib::Color::Red),
  9.           _ => None,
  10.       }
  11.   }

Update FIDL Library {#step-2}

  • Change from flexible to strict
  1. - flexible enum Color : int32 {
  2. + strict enum Color : int32 {
  3.       RED = 1;
  4.       BLUE = 2;
  5.   };

Update Source Code {#step-3}

Rust {#rust-3}

  • Remove the unreachable patterns attribute and underscore arm.
  1. - fn complement(color: &fidl_lib::Color) -> Option<fidl_lib::Color> {
  2. -     #[allow(unreachable_patterns)]
  3. + fn complement(color: &fidl_lib::Color) -> fidl_lib::Color {
  4.       match color {
  5. -         fidl_lib::Color::Red => Some(fidl_lib::Color::Blue),
  6. -         fidl_lib::Color::Blue => Some(fidl_lib::Color::Red),
  7. -         _ => None,
  8. +         fidl_lib::Color::Red => fidl_lib::Color::Blue,
  9. +         fidl_lib::Color::Blue => fidl_lib::Color::Red,
  10.       }
  11.   }