Make the "check update" interface a little cleaner

main.go

@@ -10,20 +10,15 @@ import (
 )
 
 func main() {
-	printUpdateMessage := make(chan func())
-	go update.CheckForUpdate(printUpdateMessage)
-
-	if cmd, err := command.RootCmd.ExecuteC(); err != nil {
-		fmt.Fprintln(os.Stderr, err)
-		_, isFlagError := err.(command.FlagError)
-		if isFlagError || strings.HasPrefix(err.Error(), "unknown command ") {
-			fmt.Fprintln(os.Stderr, cmd.UsageString())
+	isProduction := os.Getenv("APP_ENV") != "production"
+	update.RunWhileCheckingForUpdate(isProduction, func() {
+		if cmd, err := command.RootCmd.ExecuteC(); err != nil {
+			fmt.Fprintln(os.Stderr, err)
+			_, isFlagError := err.(command.FlagError)
+			if isFlagError || strings.HasPrefix(err.Error(), "unknown command ") {
+				fmt.Fprintln(os.Stderr, cmd.UsageString())
+			}
+			os.Exit(1)
 		}
-		os.Exit(1)
-	}
-
-	printFunc := <-printUpdateMessage
-	if printFunc != nil {
-		printFunc()
-	}
+	})
 }

update/checkForUpdate.go

@@ -19,36 +19,44 @@ type releaseInfo struct {
 	URL     string `json:"html_url"`
 }
 
-func CheckForUpdate(handleUpdate chan func()) {
-	// Only check for updates in production
-	if os.Getenv("APP_ENV") != "production" {
-		handleUpdate <- nil
+func RunWhileCheckingForUpdate(isProduction bool, f func()) {
+	if isProduction {
+		f()
 		return
 	}
 
+	newReleaseChan := make(chan *releaseInfo)
+	go checkForUpdate(newReleaseChan)
+	f()
+
+	newRelease := <-newReleaseChan
+	if newRelease != nil {
+		fmt.Printf(utils.Cyan(`
+A new version of gh is available! %s → %s
+Changelog: %s
+Run 'brew upgrade gh' to update!`)+"\n\n", command.Version, newRelease.Version, newRelease.URL)
+	}
+}
+
+func checkForUpdate(newReleaseChan chan *releaseInfo) {
 	// Ignore if this stdout is not a tty
 	if !terminal.IsTerminal(int(os.Stdout.Fd())) {
-		handleUpdate <- nil
+		newReleaseChan <- nil
 		return
 	}
 
 	latestRelease, err := getLatestRelease()
 	if err != nil {
-		handleUpdate <- nil
+		newReleaseChan <- nil
 		return
 	}
 
 	updateAvailable := latestRelease.Version != command.Version
 
 	if updateAvailable {
-		handleUpdate <- func() {
-			fmt.Printf(utils.Cyan(`
-A new version of gh is available! %s → %s
-Changelog: %s
-Run 'brew upgrade gh' to update!`)+"\n\n", command.Version, latestRelease.Version, latestRelease.URL)
-		}
+		newReleaseChan <- latestRelease
 	} else {
-		handleUpdate <- nil
+		newReleaseChan <- nil
 	}
 }