fix: re-exec binary after auto-upgrade instead of requiring manual restart

When installed via `curl | bash`, brew installs the tap version which may
be outdated. The old binary's auto-upgrade downloads the new version but
continued running the old code in memory, causing hangs in older versions.
Now uses syscall.Exec to seamlessly replace the process with the upgraded
binary.

Author: fullstackjam

internal/updater/updater.go

@@ -12,6 +12,7 @@ import (
 	"strconv"
 	"strings"
 	"sync"
+	"syscall"
 	"time"
 
 	"github.com/openbootdotdev/openboot/internal/ui"
@@ -193,8 +194,9 @@ func doBrewUpgrade(currentVersion, latestVersion string) {
 		ui.Muted("Run 'brew upgrade openboot' to update manually")
 		fmt.Println()
 	} else {
-		ui.Success(fmt.Sprintf("Updated to v%s. Restart openboot to use the new version.", latestClean))
+		ui.Success(fmt.Sprintf("Updated to v%s. Restarting...", latestClean))
 		fmt.Println()
+		execSelf()
 	}
 }
 
@@ -208,8 +210,29 @@ func doDirectUpgrade(currentVersion, latestVersion string) {
 		fmt.Println()
 		return
 	}
-	ui.Success(fmt.Sprintf("Updated to v%s. Restart openboot to use the new version.", latestClean))
+	ui.Success(fmt.Sprintf("Updated to v%s. Restarting...", latestClean))
 	fmt.Println()
+	execSelf()
+}
+
+// execSelf is a package-level variable to allow test injection.
+var execSelf = func() {
+	exe, err := os.Executable()
+	if err != nil {
+		ui.Warn(fmt.Sprintf("Could not restart: %v", err))
+		ui.Muted("Please run the command again to use the new version.")
+		return
+	}
+	exe, err = filepath.EvalSymlinks(exe)
+	if err != nil {
+		ui.Warn(fmt.Sprintf("Could not restart: %v", err))
+		ui.Muted("Please run the command again to use the new version.")
+		return
+	}
+	if err := syscall.Exec(exe, os.Args, os.Environ()); err != nil {
+		ui.Warn(fmt.Sprintf("Could not restart: %v", err))
+		ui.Muted("Please run the command again to use the new version.")
+	}
 }
 
 func DownloadAndReplace() error {

internal/updater/updater_test.go

@@ -407,9 +407,15 @@ func TestDoBrewUpgrade_Success(t *testing.T) {
 	execBrewUpgrade = func(formula string) error { calledWith = formula; return nil }
 	defer func() { execBrewUpgrade = origExec }()
 
+	restarted := false
+	origSelf := execSelf
+	execSelf = func() { restarted = true }
+	defer func() { execSelf = origSelf }()
+
 	doBrewUpgrade("1.0.0", "v2.0.0")
 
 	assert.Equal(t, brewFormula, calledWith)
+	assert.True(t, restarted, "should re-exec after successful upgrade")
 }
 
 func TestDoBrewUpgrade_Failure(t *testing.T) {
@@ -418,9 +424,15 @@ func TestDoBrewUpgrade_Failure(t *testing.T) {
 	execBrewUpgrade = func(formula string) error { called = true; return fmt.Errorf("brew failed") }
 	defer func() { execBrewUpgrade = origExec }()
 
+	restarted := false
+	origSelf := execSelf
+	execSelf = func() { restarted = true }
+	defer func() { execSelf = origSelf }()
+
 	doBrewUpgrade("1.0.0", "v2.0.0")
 
 	assert.True(t, called, "brew should have been attempted")
+	assert.False(t, restarted, "should not re-exec on failed upgrade")
 }
 
 // --- End-to-end: AutoUpgrade with Homebrew (via resolveLatestVersion) ---