protobuf-go/runtime/protoimpl/version.go
Joe Tsai bab3d4084e runtime/protoimpl, cmd/protoc-gen-go: support release versioning
In order for protoc-gen-go to output the current version,
it needs to know what version it is currently running as.
However, we cannot rely on the git tags since the tags are not
made until *after* the commit has been submitted.
Instead, we manually encode the version into the code and
make sure that git tags match up with the version in the code.

The version.go file in runtime/protoimpl contains instructions
for how to make a release. Essentially:
* Every non-release commit has a version string with "devel" in it.
* Every release commit must not have "devel" in it and must be unique.
* The "release process" involves submitting two CLs.
The first CL creates a version string without "devel",
which is the commit that a git tag will actually reference.
The second CL follows immediately and re-introduces "devel"
into the version string.

The following example shows a possible sequence of VersionStrings
for git commits in time-ascending order:
	v1.19.0-devel      (this CL)
	v1.19.0-devel
	v1.19.0-devel
	v1.19.0-devel
	v1.20.0-rc.1       <- tagged
	v1.20.0-rc.1.devel
	v1.20.0-rc.1.devel
	v1.20.0-rc.1.devel
	v1.20.0-rc.2       <- tagged
	v1.20.0-rc.2.devel
	v1.20.0            <- tagged (future public release)
	v1.20.0-devel
	v1.20.0-devel
	v1.20.0-devel
	v1.20.0-devel
	v1.20.1            <- tagged
	v1.20.1-devel
	v1.20.1-devel
	v1.21.0            <- tagged
	v1.21.0-devel

Note that we start today with v1.19.0-devel, which means that our initial
release will be v1.20.0. This number was intentionally chosen since
1) the number 20 has some correlation to the fact that we keep calling
the new implementation the "v2" implementation, and
2) the set of tagged versions for github.com/golang/protobuf
and google.golang.org/protobuf are unlikely to ever overlap.
This way, the version of protoc-gen-go is never ambiguous which module
it was built from.

Now that we have version information, we add support for generating .pb.go
files with the version information recorded. However, we do not emit
these for .pb.go files in our own repository since they are always guaranteed
to be at the right version (enforced by integration_test.go).

Updates golang/protobuf#524

Change-Id: I25495a45042c2aa39a39cb7e7738ae8e831a9d26
Reviewed-on: https://go-review.googlesource.com/c/protobuf/+/186117
Reviewed-by: Damien Neil <dneil@google.com>
2019-08-07 22:59:30 +00:00

126 lines
4.1 KiB
Go

// Copyright 2019 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package protoimpl
import (
"fmt"
"strings"
)
// These constants determine the current version of this module.
//
//
// For our release process, we enforce the following rules:
// * Tagged releases use a tag that is identical to VersionString.
// * Tagged releases never reference a commit where the VersionString
// contains "devel".
// * The set of all commits in this repository where VersionString
// does not contain "devel" must have a unique VersionString.
//
//
// Steps for tagging a new release:
// 1. Create a new CL.
//
// 2. Update versionMinor, versionPatch, and/or versionPreRelease as necessary.
// versionPreRelease must not contain the string "devel".
//
// 3. Since the last released minor version, have there been any changes to
// generator that relies on new functionality in the runtime?
// If yes, then increment GenVersion.
//
// 4. Since the last released minor version, have there been any changes to
// the runtime that removes support for old .pb.go source code?
// If yes, then increment MinVersion.
//
// 5. Send out the CL for review and submit it.
// Note that the next CL in step 8 must be submitted after this CL
// without any other CLs in-between.
//
// 6. Tag a new version, where the tag is is the current VersionString.
//
// 7. Write release notes for all notable changes
// between this release and the last release.
//
// 8. Create a new CL.
//
// 9. Update versionPreRelease to include the string "devel".
// For example: "" -> "devel" or "rc.1" -> "rc.1.devel"
//
// 10. Send out the CL for review and submit it.
const (
versionMajor = 1
versionMinor = 19
versionPatch = 0
versionPreRelease = "devel"
)
// VersionString formats the version string for this module in semver format.
//
// Examples:
// v1.20.1
// v1.21.0-rc.1
func VersionString() string {
v := fmt.Sprintf("v%d.%d.%d", versionMajor, versionMinor, versionPatch)
if versionPreRelease != "" {
v += "-" + versionPreRelease
// TODO: Add metadata about the commit or build hash.
// See https://golang.org/issue/29814
// See https://golang.org/issue/33533
var versionMetadata string
if strings.Contains(versionPreRelease, "devel") && versionMetadata != "" {
v += "+" + versionMetadata
}
}
return v
}
const (
// MaxVersion is the maximum supported version for generated .pb.go files.
// It is always the current version of the module.
MaxVersion = versionMinor
// GenVersion is the runtime version required by generated .pb.go files.
// This is incremented when generated code relies on new functionality
// in the runtime.
GenVersion = 19
// MinVersion is the minimum supported version for generated .pb.go files.
// This is incremented when the runtime drops support for old code.
MinVersion = 0
)
// EnforceVersion is used by code generated by protoc-gen-go
// to statically enforce minimum and maximum versions of this package.
// A compilation failure implies either that:
// * the runtime package is too old and needs to be updated OR
// * the generated code is too old and needs to be regenerated.
//
// The runtime package can be upgraded by running:
// go get google.golang.org/protobuf
//
// The generated code can be regenerated by running:
// protoc --go_out=${PROTOC_GEN_GO_ARGS} ${PROTO_FILES}
//
// Example usage by generated code:
// const (
// // Verify that this generated code is sufficiently up-to-date.
// _ = protoimpl.EnforceVersion(genVersion - protoimpl.MinVersion)
// // Verify that runtime/protoimpl is sufficiently up-to-date.
// _ = protoimpl.EnforceVersion(protoimpl.MaxVersion - genVersion)
// )
//
// The genVersion is the current minor version used to generated the code.
// This compile-time check relies on negative integer overflow of a uint
// being a compilation failure (guaranteed by the Go specification).
type EnforceVersion uint
// This enforces the following invariant:
// MinVersion ≤ GenVersion ≤ MaxVersion
const (
_ = EnforceVersion(GenVersion - MinVersion)
_ = EnforceVersion(MaxVersion - GenVersion)
)