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 //	go get google.golang.org/protobuf

    34 //

    35 // The generated code can be regenerated by running:

    36 //	protoc --go_out=${PROTOC_GEN_GO_ARGS} ${PROTO_FILES}

    37 //

    38 // Example usage by generated code:

    39 //	const (

    40 //		// Verify that this generated code is sufficiently up-to-date.

    41 //		_ = protoimpl.EnforceVersion(genVersion - protoimpl.MinVersion)

    42 //		// Verify that runtime/protoimpl is sufficiently up-to-date.

    43 //		_ = protoimpl.EnforceVersion(protoimpl.MaxVersion - genVersion)

    44 //	)

    45 //

    46 // The genVersion is the current minor version used to generated the code.

    47 // This compile-time check relies on negative integer overflow of a uint

    48 // being a compilation failure (guaranteed by the Go specification).

    49 type EnforceVersion uint

    50 

    51 // This enforces the following invariant:

    52 //	MinVersion ≤ GenVersion ≤ MaxVersion

    53 const (

    54 	_ = EnforceVersion(GenVersion - MinVersion)

    55 	_ = EnforceVersion(MaxVersion - GenVersion)

    56 )