2023 年 6 月 29 日宣布的变更

// proto2 file
syntax = "proto2";

message Player {
  // in proto2, optional fields have explicit presence
  optional string name = 1;
  // proto2 still supports the problematic "required" field rule
  required int32 id = 2;
  // in proto2 this is not packed by default
  repeated int32 scores = 3;

  enum Handed {
    HANDED_UNSPECIFIED = 0,
    HANDED_LEFT = 1,
    HANDED_RIGHT = 2,
    HANDED_AMBIDEXTROUS = 3,
  }

  // in proto2 enums are closed
  optional Handed handed = 4;
}

// Editions version of proto2 file
edition = "2023";

message Player {
  string name = 1;
  int32 id = 2 [features.field_presence = LEGACY_REQUIRED];
  repeated int32 scores = 3 [features.repeated_field_encoding = EXPANDED];

  enum Handed {
    // this overrides the default Edition 2023 behavior, which is OPEN
    option features.enum = CLOSED;
    HANDED_UNSPECIFIED = 0,
    HANDED_LEFT = 1,
    HANDED_RIGHT = 2,
    HANDED_AMBIDEXTROUS = 3,
  }

  Handed handed = 4;
}

// proto3 file
syntax = "proto3";

message Player {
  // in proto3, optional fields have explicit presence
  optional string name = 1;
  // in proto3 no specified field rule defaults to implicit presence
  int32 id = 2;
  // in proto3 this is packed by default
  repeated int32 scores = 3;

  enum Handed {
    HANDED_UNSPECIFIED = 0,
    HANDED_LEFT = 1,
    HANDED_RIGHT = 2,
    HANDED_AMBIDEXTROUS = 3,
  }

  // in proto3 enums are open
  optional Handed handed = 4;
}

// Editions version of proto3 file
edition = "2023";

message Player {
  string name = 1;
  int32 id = 2 [features.field_presence = IMPLICIT];
  repeated int32 scores = 3;

  enum Handed {
    HANDED_UNSPECIFIED = 0,
    HANDED_LEFT = 1,
    HANDED_RIGHT = 2,
    HANDED_AMBIDEXTROUS = 3,
  }

  Handed handed = 4;
}