gopls/internal/lsp/debug: remove hard-coded version

Just use main module information for producing the gopls version, saving
us a CL during the release process.

This means that we won't see a version if gopls is built in GOPATH mode,
but we probably should support this installation mode (if it even
works...).

Change-Id: Ib964b2dd6b2cf202805507a47f04b5077f4d24c3
Reviewed-on: https://go-review.googlesource.com/c/tools/+/522184
gopls-CI: kokoro <noreply+kokoro@google.com>
Reviewed-by: Hyang-Ah Hana Kim <hyangah@gmail.com>
Run-TryBot: Robert Findley <rfindley@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>

gopls/internal/lsp/cmd/stats.go

@@ -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: debug.Version(),
 	}
 
 	opts := s.app.options

gopls/internal/lsp/cmd/test/integration_test.go

@@ -55,7 +55,7 @@ func TestVersion(t *testing.T) {
 	tree := writeTree(t, "")
 
 	// There's not much we can robustly assert about the actual version.
-	const want = debug.Version // e.g. "master"
+	want := debug.Version() // e.g. "master"
 
 	// basic
 	{

gopls/internal/lsp/debug/info.go

@@ -30,36 +30,38 @@ const (
 )
 
 // Version is a manually-updated mechanism for tracking versions.
-const Version = "master"
+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 {
-	*BuildInfo
+	*debug.BuildInfo
 	Version string
 }
 
 // VersionInfo returns the build info for the gopls process. If it was not
 // built in module mode, we return a GOPATH-specific message with the
 // hardcoded version.
 func VersionInfo() *ServerVersion {
-	if info, ok := readBuildInfo(); ok {
-		return getVersion(info)
-	}
-	buildInfo := &BuildInfo{}
-	// go1.17 or earlier, part of s.BuildInfo are embedded fields.
-	buildInfo.Path = "gopls, built in GOPATH mode"
-	buildInfo.GoVersion = runtime.Version()
-	return &ServerVersion{
-		Version:   Version,
-		BuildInfo: buildInfo,
+	if info, ok := debug.ReadBuildInfo(); ok {
+		return &ServerVersion{
+			Version:   Version(),
+			BuildInfo: info,
+		}
 	}
-}
-
-func getVersion(info *BuildInfo) *ServerVersion {
 	return &ServerVersion{
-		Version:   Version,
-		BuildInfo: info,
+		Version: Version(),
+		BuildInfo: &debug.BuildInfo{
+			Path:      "gopls, built in GOPATH mode",
+			GoVersion: runtime.Version(),
+		},
 	}
 }
 
@@ -125,7 +127,7 @@ 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)
+	fmt.Fprintf(w, "%v %v\n", info.Path, Version())
 	printModuleInfo(w, info.Main, mode)
 	if !verbose {
 		return

gopls/internal/lsp/debug/info_test.go

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