gopls: add a main.version variable to override the version at linktime

As discussed in golang/go#63803, add a version variable to allow package
managers to set the gopls version at linktime, thereby avoiding the need
to patch source.

Fixes golang/go#63803

Change-Id: Ie6696283e1007577e82d96f01c96e16e89cfcb6f
Reviewed-on: https://go-review.googlesource.com/c/tools/+/555457
Reviewed-by: Alan Donovan <adonovan@google.com>
Auto-Submit: Robert Findley <rfindley@google.com>
Reviewed-by: Hyang-Ah Hana Kim <hyangah@gmail.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>

gopls/internal/cmd/integration_test.go

@@ -43,6 +43,7 @@ import (
 	"golang.org/x/tools/gopls/internal/hooks"
 	"golang.org/x/tools/gopls/internal/lsp/protocol"
 	"golang.org/x/tools/gopls/internal/util/bug"
+	"golang.org/x/tools/gopls/internal/version"
 	"golang.org/x/tools/internal/testenv"
 	"golang.org/x/tools/internal/tool"
 	"golang.org/x/tools/txtar"
@@ -55,7 +56,7 @@ func TestVersion(t *testing.T) {
 	tree := writeTree(t, "")
 
 	// There's not much we can robustly assert about the actual version.
-	want := debug.Version() // e.g. "master"
+	want := version.Version() // e.g. "master"
 
 	// basic
 	{
@@ -64,6 +65,13 @@ func TestVersion(t *testing.T) {
 		res.checkStdout(want)
 	}
 
+	// basic, with version override
+	{
+		res := goplsWithEnv(t, tree, []string{"TEST_GOPLS_VERSION=v1.2.3"}, "version")
+		res.checkExit(true)
+		res.checkStdout(`v1\.2\.3`)
+	}
+
 	// -json flag
 	{
 		res := gopls(t, tree, "version", "-json")
@@ -1034,6 +1042,10 @@ func goplsMain() {
 		bug.PanicOnBugs = true
 	}
 
+	if v := os.Getenv("TEST_GOPLS_VERSION"); v != "" {
+		version.VersionOverride = v
+	}
+
 	tool.Main(context.Background(), cmd.New(hooks.Options), os.Args[1:])
 }
 

gopls/internal/cmd/stats.go

@@ -19,13 +19,13 @@ import (
 	"sync"
 	"time"
 
-	"golang.org/x/tools/gopls/internal/debug"
 	"golang.org/x/tools/gopls/internal/filecache"
 	"golang.org/x/tools/gopls/internal/lsp/command"
 	"golang.org/x/tools/gopls/internal/lsp/protocol"
 	"golang.org/x/tools/gopls/internal/server"
 	"golang.org/x/tools/gopls/internal/settings"
-	goplsbug "golang.org/x/tools/gopls/internal/util/bug"
+	bugpkg "golang.org/x/tools/gopls/internal/util/bug"
+	versionpkg "golang.org/x/tools/gopls/internal/version"
 	"golang.org/x/tools/internal/event"
 )
 
@@ -74,7 +74,7 @@ func (s *stats) Run(ctx context.Context, args ...string) error {
 		GOARCH:           runtime.GOARCH,
 		GOPLSCACHE:       os.Getenv("GOPLSCACHE"),
 		GoVersion:        runtime.Version(),
-		GoplsVersion:     debug.Version(),
+		GoplsVersion:     versionpkg.Version(),
 		GOPACKAGESDRIVER: os.Getenv("GOPACKAGESDRIVER"),
 	}
 
@@ -147,7 +147,7 @@ func (s *stats) Run(ctx context.Context, args ...string) error {
 	do("Gathering bug reports", func() error {
 		stats.CacheDir, stats.BugReports = filecache.BugReports()
 		if stats.BugReports == nil {
-			stats.BugReports = []goplsbug.Bug{} // non-nil for JSON
+			stats.BugReports = []bugpkg.Bug{} // non-nil for JSON
 		}
 		return nil
 	})
@@ -232,7 +232,7 @@ type GoplsStats struct {
 	GOPACKAGESDRIVER             string
 	InitialWorkspaceLoadDuration string `anon:"ok"` // in time.Duration string form
 	CacheDir                     string
-	BugReports                   []goplsbug.Bug
+	BugReports                   []bugpkg.Bug
 	MemStats                     command.MemStatsResult       `anon:"ok"`
 	WorkspaceStats               command.WorkspaceStatsResult `anon:"ok"`
 	DirStats                     dirStats                     `anon:"ok"`

gopls/internal/debug/info.go

@@ -14,6 +14,8 @@ import (
 	"runtime"
 	"runtime/debug"
 	"strings"
+
+	"golang.org/x/tools/gopls/internal/version"
 )
 
 type PrintMode int
@@ -25,16 +27,6 @@ const (
 	JSON
 )
 
-// Version is a manually-updated mechanism for tracking versions.
-func Version() string {
-	if info, ok := debug.ReadBuildInfo(); ok {
-		if info.Main.Version != "" {
-			return info.Main.Version
-		}
-	}
-	return "(unknown)"
-}
-
 // ServerVersion is the format used by gopls to report its version to the
 // client. This format is structured so that the client can parse it easily.
 type ServerVersion struct {
@@ -48,12 +40,12 @@ type ServerVersion struct {
 func VersionInfo() *ServerVersion {
 	if info, ok := debug.ReadBuildInfo(); ok {
 		return &ServerVersion{
-			Version:   Version(),
+			Version:   version.Version(),
 			BuildInfo: info,
 		}
 	}
 	return &ServerVersion{
-		Version: Version(),
+		Version: version.Version(),
 		BuildInfo: &debug.BuildInfo{
 			Path:      "gopls, built in GOPATH mode",
 			GoVersion: runtime.Version(),
@@ -124,11 +116,11 @@ func section(w io.Writer, mode PrintMode, title string, body func()) {
 }
 
 func printBuildInfo(w io.Writer, info *ServerVersion, verbose bool, mode PrintMode) {
-	fmt.Fprintf(w, "%v %v\n", info.Path, Version())
-	printModuleInfo(w, info.Main, mode)
+	fmt.Fprintf(w, "%v %v\n", info.Path, version.Version())
 	if !verbose {
 		return
 	}
+	printModuleInfo(w, info.Main, mode)
 	for _, dep := range info.Deps {
 		printModuleInfo(w, *dep, mode)
 	}

gopls/internal/debug/info_test.go

@@ -11,6 +11,8 @@ import (
 	"encoding/json"
 	"runtime"
 	"testing"
+
+	"golang.org/x/tools/gopls/internal/version"
 )
 
 func TestPrintVersionInfoJSON(t *testing.T) {
@@ -27,7 +29,7 @@ func TestPrintVersionInfoJSON(t *testing.T) {
 	if g, w := got.GoVersion, runtime.Version(); g != w {
 		t.Errorf("go version = %v, want %v", g, w)
 	}
-	if g, w := got.Version, Version(); g != w {
+	if g, w := got.Version, version.Version(); g != w {
 		t.Errorf("gopls version = %v, want %v", g, w)
 	}
 	// Other fields of BuildInfo may not be available during test.
@@ -41,7 +43,7 @@ func TestPrintVersionInfoPlainText(t *testing.T) {
 	res := buf.Bytes()
 
 	// Other fields of BuildInfo may not be available during test.
-	wantGoplsVersion, wantGoVersion := Version(), runtime.Version()
+	wantGoplsVersion, wantGoVersion := version.Version(), runtime.Version()
 	if !bytes.Contains(res, []byte(wantGoplsVersion)) || !bytes.Contains(res, []byte(wantGoVersion)) {
 		t.Errorf("plaintext output = %q,\nwant (version: %v, go: %v)", res, wantGoplsVersion, wantGoVersion)
 	}

gopls/internal/version/version.go

@@ -0,0 +1,29 @@
+// 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 version manages the gopls version.
+//
+// The VersionOverride variable may be used to set the gopls version at link
+// time.
+package version
+
+import "runtime/debug"
+
+var VersionOverride = ""
+
+// Version returns the gopls version.
+//
+// By default, this is read from runtime/debug.ReadBuildInfo, but may be
+// overridden by the [VersionOverride] variable.
+func Version() string {
+	if VersionOverride != "" {
+		return VersionOverride
+	}
+	if info, ok := debug.ReadBuildInfo(); ok {
+		if info.Main.Version != "" {
+			return info.Main.Version
+		}
+	}
+	return "(unknown)"
+}

gopls/main.go

@@ -20,10 +20,15 @@ import (
 	"golang.org/x/telemetry/counter"
 	"golang.org/x/tools/gopls/internal/cmd"
 	"golang.org/x/tools/gopls/internal/hooks"
+	versionpkg "golang.org/x/tools/gopls/internal/version"
 	"golang.org/x/tools/internal/tool"
 )
 
+var version = "" // if set by the linker, overrides the gopls version
+
 func main() {
+	versionpkg.VersionOverride = version
+
 	counter.Open() // Enable telemetry counter writing.
 	ctx := context.Background()
 	tool.Main(ctx, cmd.New(hooks.Options), os.Args[1:])