version: unify and optimize the various not-version funcs

Signed-off-by: David Anderson <danderson@tailscale.com>

version/prop.go

@@ -4,107 +4,35 @@
 package version
 
 import (
-	"os"
-	"path/filepath"
-	"runtime"
-	"strconv"
 	"strings"
-	"sync"
 
 	tailscaleroot "tailscale.com"
-	"tailscale.com/syncs"
 	"tailscale.com/tailcfg"
 )
 
 // IsMobile reports whether this is a mobile client build.
-func IsMobile() bool {
+func IsMobile() bool { return isMobile }
-	return runtime.GOOS == "android" || runtime.GOOS == "ios"
-}
 
 // OS returns runtime.GOOS, except instead of returning "darwin" it
 // returns "iOS" or "macOS".
-func OS() string {
+func OS() string { return legacyOS }
-	if runtime.GOOS == "ios" {
-		return "iOS"
-	}
-	if runtime.GOOS == "darwin" {
-		return "macOS"
-	}
-	return runtime.GOOS
-}
 
 // IsSandboxedMacOS reports whether this process is a sandboxed macOS
 // process (either the app or the extension). It is true for the Mac App Store
 // and macsys (System Extension) version on macOS, and false for
 // tailscaled-on-macOS.
-func IsSandboxedMacOS() bool {
+func IsSandboxedMacOS() bool { return isSandboxedMacOS }
-	if runtime.GOOS != "darwin" {
-		return false
-	}
-	if IsMacSysExt() {
-		return true
-	}
-	exe, _ := os.Executable()
-	return strings.HasSuffix(exe, "/Contents/MacOS/Tailscale") || strings.HasSuffix(exe, "/Contents/MacOS/IPNExtension")
-}
-
-var isMacSysExt syncs.AtomicValue[bool]
 
 // IsMacSysExt whether this binary is from the standalone "System
 // Extension" (a.k.a. "macsys") version of Tailscale for macOS.
-func IsMacSysExt() bool {
+func IsMacSysExt() bool { return isMacSysExt }
-	if runtime.GOOS != "darwin" {
-		return false
-	}
-	if b, ok := isMacSysExt.LoadOk(); ok {
-		return b
-	}
-	exe, err := os.Executable()
-	if err != nil {
-		return false
-	}
-	v := filepath.Base(exe) == "io.tailscale.ipn.macsys.network-extension"
-	isMacSysExt.Store(v)
-	return v
-}
 
 // IsWindowsGUI reports whether the current process is the Windows GUI.
-func IsWindowsGUI() bool {
+func IsWindowsGUI() bool { return isWindowsGUI }
-	if runtime.GOOS != "windows" {
-		return false
-	}
-	exe, _ := os.Executable()
-	exe = filepath.Base(exe)
-	return strings.EqualFold(exe, "tailscale-ipn.exe") || strings.EqualFold(exe, "tailscale-ipn")
-}
-
-var (
-	isUnstableOnce  sync.Once
-	isUnstableBuild bool
-)
 
 // IsUnstableBuild reports whether this is an unstable build.
 // That is, whether its minor version number is odd.
-func IsUnstableBuild() bool {
+func IsUnstableBuild() bool { return isUnstable }
-	isUnstableOnce.Do(initUnstable)
-	return isUnstableBuild
-}
-
-func initUnstable() {
-	_, rest, ok := strings.Cut(Short, ".")
-	if !ok {
-		return
-	}
-	minorStr, _, ok := strings.Cut(rest, ".")
-	if !ok {
-		return
-	}
-	minor, err := strconv.Atoi(minorStr)
-	if err != nil {
-		return
-	}
-	isUnstableBuild = minor%2 == 1
-}
 
 // Meta is a JSON-serializable type that contains all the version
 // information.

version/version.go

@@ -5,34 +5,97 @@
 package version
 
 import (
+	"os"
+	"path/filepath"
+	"runtime"
 	"runtime/debug"
+	"strconv"
 	"strings"
 
 	tailscaleroot "tailscale.com"
 )
 
-// Long is a full version number for this build, of the form
+var (
-// "x.y.z-commithash" for builds stamped in the usual way (see
+	// Long is a full version number for this build, of the form
-// build_dist.sh in the root) or, for binaries built by hand with the
+	// "x.y.z-commithash" for builds stamped in the usual way (see build_dist.sh
-// go tool, it's of the form "1.23.0-dev20220316-t29837428937{,-dirty}"
+	// in the root) or, for binaries built by hand with the go tool, it's of the
-// where "1.23.0" comes from ../VERSION.txt and the part after dev
+	// form "1.23.0-dev20220316-t29837428937{,-dirty}" where "1.23.0" comes from
-// is YYYYMMDD of the commit time, and the part after -t is the commit
+	// ../VERSION.txt and the part after dev is YYYYMMDD of the commit time, and
-// hash. The dirty suffix is whether there are uncommitted changes.
+	// the part after -t is the commit hash. The dirty suffix is whether there
-var Long = ""
+	// are uncommitted changes.
+	Long string
 
-// Short is a short version number for this build, of the form
+	// Short is a short version number for this build, of the form
-// "x.y.z" for builds stamped in the usual way (see
+	// "x.y.z" for builds stamped in the usual way (see
-// build_dist.sh in the root) or, for binaries built by hand with the
+	// build_dist.sh in the root) or, for binaries built by hand with the
-// go tool, it's like Long's dev form, but ending at the date part,
+	// go tool, it's like Long's dev form, but ending at the date part,
-// of the form "1.23.0-dev20220316".
+	// of the form "1.23.0-dev20220316".
-var Short = ""
+	Short string
+
+	// GitCommit, if non-empty, is the git commit of the
+	// github.com/tailscale/tailscale repository at which Tailscale was
+	// built. Its format is the one returned by `git describe --always
+	// --exclude "*" --dirty --abbrev=200`.
+	GitCommit string
+
+	// GitDirty is whether Go stamped the binary as having dirty version
+	// control changes in the working directory (debug.ReadBuildInfo
+	// setting "vcs.modified" was true).
+	GitDirty bool
+
+	// ExtraGitCommit, if non-empty, is the git commit of a "supplemental"
+	// repository at which Tailscale was built. Its format is the same as
+	// gitCommit.
+	//
+	// ExtraGitCommit is used to track the source revision when the main
+	// Tailscale repository is integrated into and built from another
+	// repository (for example, Tailscale's proprietary code, or the
+	// Android OSS repository). Together, GitCommit and ExtraGitCommit
+	// exactly describe what repositories and commits were used in a
+	// build.
+	ExtraGitCommit = ""
+
+	// isUnstable is whether the current build appears to be an unstable, i.e. with
+	// an odd minor version number.
+	isUnstable bool
+
+	// legacyOS is runtime.GOOS, except on apple devices where it's either "iOS" or
+	// "macOS" (with that exact case).
+	//
+	// This used to be a thing because Go reported both macOS and iOS as "darwin"
+	// and we needed to tell them apart. But then Go learned GOOS=ios and
+	// GOOS=darwin as separate things, but we're still stuck with this function
+	// because of the odd casing we picked, which has ossified into databases.
+	legacyOS string
+
+	// isMobile is whether the current build is for a mobile device.
+	isMobile bool
+
+	// isSandboxedMacOS is whether the current binary is any binary in the mac store
+	// or standalone sysext mac apps.
+	isSandboxedMacOS bool
+
+	// isMacSysExt is whether the current binary is the mac system extension binary.
+	isMacSysExt bool
+
+	// isWindowsGUI is whether the current binary is the Windows GUI binary.
+	isWindowsGUI bool
+)
 
 func init() {
+	initVersion()
+	initUnstable()
+	initMiscTraits()
+}
+
+func initVersion() {
 	if Long != "" && Short != "" {
 		// Built in the recommended way, using build_dist.sh.
 		return
 	}
 
+	// Otherwise, make approximate version info using Go 1.18's built-in git
+	// stamping.
 	bi, ok := debug.ReadBuildInfo()
 	if !ok {
 		Long = strings.TrimSpace(tailscaleroot.Version) + "-ERR-BuildInfo"
@@ -67,25 +130,38 @@ func init() {
 	Long = Short + "-t" + commitHashAbbrev + dirty
 }
 
-// GitCommit, if non-empty, is the git commit of the
+func initUnstable() {
-// github.com/tailscale/tailscale repository at which Tailscale was
+	_, rest, ok := strings.Cut(Short, ".")
-// built. Its format is the one returned by `git describe --always
+	if !ok {
-// --exclude "*" --dirty --abbrev=200`.
+		return
-var GitCommit = ""
+	}
+	minorStr, _, ok := strings.Cut(rest, ".")
+	if !ok {
+		return
+	}
+	minor, err := strconv.Atoi(minorStr)
+	if err != nil {
+		return
+	}
+	isUnstable = minor%2 == 1
+}
 
-// GitDirty is whether Go stamped the binary as having dirty version
+func initMiscTraits() {
-// control changes in the working directory (debug.ReadBuildInfo
+	exe, _ := os.Executable()
-// setting "vcs.modified" was true).
+	base := filepath.Base(exe)
-var GitDirty bool
 
-// ExtraGitCommit, if non-empty, is the git commit of a "supplemental"
+	legacyOS = runtime.GOOS
-// repository at which Tailscale was built. Its format is the same as
+	switch runtime.GOOS {
-// gitCommit.
+	case "darwin":
-//
+		legacyOS = "macOS"
-// ExtraGitCommit is used to track the source revision when the main
+		isMacSysExt = strings.HasPrefix(base, "io.tailscale.ipn.macsys.network-extension")
-// Tailscale repository is integrated into and built from another
+		isSandboxedMacOS = isMacSysExt || strings.HasSuffix(exe, "/Contents/MacOS/Tailscale") || strings.HasSuffix(exe, "/Contents/MacOS/IPNExtension")
-// repository (for example, Tailscale's proprietary code, or the
+	case "ios":
-// Android OSS repository). Together, GitCommit and ExtraGitCommit
+		legacyOS = "iOS"
-// exactly describe what repositories and commits were used in a
+		isMobile = true
-// build.
+	case "android":
-var ExtraGitCommit = ""
+		isMobile = true
+	case "windows":
+		isWindowsGUI = strings.EqualFold(base, "tailscale-ipn.exe") || strings.EqualFold(base, "tailscale-ipn")
+	}
+}