1 // Copyright 2019 The Go Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style
3 // license that can be found in the LICENSE file.
4 5 package protoimpl
6 7 import (
8 "google.golang.org/protobuf/internal/version"
9 )
10 11 const (
12 // MaxVersion is the maximum supported version for generated .pb.go files.
13 // It is always the current version of the module.
14 MaxVersion = version.Minor
15 16 // GenVersion is the runtime version required by generated .pb.go files.
17 // This is incremented when generated code relies on new functionality
18 // in the runtime.
19 GenVersion = 20
20 21 // MinVersion is the minimum supported version for generated .pb.go files.
22 // This is incremented when the runtime drops support for old code.
23 MinVersion = 0
24 )
25 26 // EnforceVersion is used by code generated by protoc-gen-go
27 // to statically enforce minimum and maximum versions of this package.
28 // A compilation failure implies either that:
29 // - the runtime package is too old and needs to be updated OR
30 // - the generated code is too old and needs to be regenerated.
31 //
32 // The runtime package can be upgraded by running:
33 //
34 // go get google.golang.org/protobuf
35 //
36 // The generated code can be regenerated by running:
37 //
38 // protoc --go_out=${PROTOC_GEN_GO_ARGS} ${PROTO_FILES}
39 //
40 // Example usage by generated code:
41 //
42 // const (
43 // // Verify that this generated code is sufficiently up-to-date.
44 // _ = protoimpl.EnforceVersion(genVersion - protoimpl.MinVersion)
45 // // Verify that runtime/protoimpl is sufficiently up-to-date.
46 // _ = protoimpl.EnforceVersion(protoimpl.MaxVersion - genVersion)
47 // )
48 //
49 // The genVersion is the current minor version used to generated the code.
50 // This compile-time check relies on negative integer overflow of a uint
51 // being a compilation failure (guaranteed by the Go specification).
52 type EnforceVersion uint
53 54 // This enforces the following invariant:
55 //
56 // MinVersion ≤ GenVersion ≤ MaxVersion
57 const (
58 _ = EnforceVersion(GenVersion - MinVersion)
59 _ = EnforceVersion(MaxVersion - GenVersion)
60 )
61