Avoid showing panics directly if debug mode is not enabled

gomuks.go

@@ -17,8 +17,10 @@
 package main
 
 import (
+	"fmt"
 	"os"
 	"path/filepath"
+	"time"
 
 	"maunium.net/go/gomatrix"
 	"maunium.net/go/gomuks/config"
@@ -29,17 +31,18 @@ import (
 	"maunium.net/go/tview"
 )
 
-type gomuks struct {
+type Gomuks struct {
 	app       *tview.Application
 	ui        *ui.GomuksUI
 	matrix    *matrix.Container
 	debug     *debug.Pane
+	debugMode bool
 	config    *config.Config
 }
 
-func NewGomuks(enableDebug bool) *gomuks {
+func NewGomuks(enableDebug bool) *Gomuks {
 	configDir := filepath.Join(os.Getenv("HOME"), ".config/gomuks")
-	gmx := &gomuks{
+	gmx := &Gomuks{
 		app: tview.NewApplication(),
 	}
 
@@ -63,13 +66,14 @@ func NewGomuks(enableDebug bool) *gomuks {
 	main := gmx.ui.InitViews()
 	if enableDebug {
 		main = gmx.debug.Wrap(main)
+		gmx.debugMode = true
 	}
 	gmx.app.SetRoot(main, true)
 
 	return gmx
 }
 
-func (gmx *gomuks) Stop() {
+func (gmx *Gomuks) Stop() {
 	gmx.debug.Print("Disconnecting from Matrix...")
 	gmx.matrix.Stop()
 	gmx.debug.Print("Cleaning up UI...")
@@ -78,44 +82,54 @@ func (gmx *gomuks) Stop() {
 		gmx.debug.Print("Saving session...")
 		gmx.config.Session.Save()
 	}
+	os.Exit(0)
 }
 
-func (gmx *gomuks) Recover() {
+func (gmx *Gomuks) Recover() {
 	if p := recover(); p != nil {
 		if gmx.App().GetScreen() != nil {
 			gmx.App().GetScreen().Fini()
 		}
+		if gmx.debugMode {
 			panic(p)
+		} else {
+			debug.PrettyPanic()
+		}
 	}
 }
 
-func (gmx *gomuks) Start() {
+func (gmx *Gomuks) Start() {
 	if err := gmx.app.Run(); err != nil {
 		panic(err)
 	}
 }
 
-func (gmx *gomuks) Matrix() *gomatrix.Client {
+func (gmx *Gomuks) Matrix() *gomatrix.Client {
 	return gmx.matrix.Client()
 }
 
-func (gmx *gomuks) MatrixContainer() ifc.MatrixContainer {
+func (gmx *Gomuks) MatrixContainer() ifc.MatrixContainer {
 	return gmx.matrix
 }
 
-func (gmx *gomuks) App() *tview.Application {
+func (gmx *Gomuks) App() *tview.Application {
 	return gmx.app
 }
 
-func (gmx *gomuks) Config() *config.Config {
+func (gmx *Gomuks) Config() *config.Config {
 	return gmx.config
 }
 
-func (gmx *gomuks) UI() ifc.GomuksUI {
+func (gmx *Gomuks) UI() ifc.GomuksUI {
 	return gmx.ui
 }
 
 func main() {
-	debug := os.Getenv("DEBUG")
-	NewGomuks(len(debug) > 0).Start()
+	enableDebug := len(os.Getenv("DEBUG")) > 0
+	NewGomuks(enableDebug).Start()
+
+	// We use os.Exit() everywhere, so exiting by returning from Start() shouldn't happen.
+	time.Sleep(5 * time.Second)
+	fmt.Println("Unexpected exit by return from Gomuks#Start().")
+	os.Exit(2)
 }

matrix/matrix.go

@@ -198,13 +198,13 @@ func (c *Container) HandleTyping(evt *gomatrix.Event) {
 }
 
 func (c *Container) SendMessage(roomID, message string) {
-	c.gmx.Recover()
+	defer c.gmx.Recover()
 	c.SendTyping(roomID, false)
 	c.client.SendText(roomID, message)
 }
 
 func (c *Container) SendTyping(roomID string, typing bool) {
-	c.gmx.Recover()
+	defer c.gmx.Recover()
 	ts := time.Now().Unix()
 	if c.typing > ts && typing {
 		return

ui/debug/debug.go

@@ -18,6 +18,11 @@ package debug
 
 import (
 	"fmt"
+	"io/ioutil"
+	"os"
+	"time"
+
+	"runtime/debug"
 
 	"maunium.net/go/tview"
 )
@@ -81,3 +86,41 @@ func Print(text ...interface{}) {
 		Default.Print(text...)
 	}
 }
+
+const Oops = ` __________
+< Oh noes! >
+ ‾‾‾\‾‾‾‾‾‾
+     \   ^__^
+      \  (XX)\_______
+         (__)\       )\/\
+          U  ||----W |
+             ||     ||`
+
+func PrettyPanic() {
+	fmt.Println(Oops)
+	fmt.Println("")
+	fmt.Println("A fatal error has occurred.")
+	fmt.Println("")
+	traceFile := fmt.Sprintf("/tmp/gomuks-panic-%s.txt", time.Now().Format("2006-01-02--15-04-05"))
+	data := debug.Stack()
+	err := ioutil.WriteFile(traceFile, data, 0644)
+	if err != nil {
+		fmt.Println("Saving the stack trace to", traceFile, "failed:")
+		fmt.Println("--------------------------------------------------------------------------------")
+		fmt.Println(err)
+		fmt.Println("--------------------------------------------------------------------------------")
+		fmt.Println("")
+		fmt.Println("You can file an issue at https://github.com/tulir/gomuks/issues.")
+		fmt.Println("Please provide the file save error (above) and the stack trace of the original error (below) when filing an issue.")
+		fmt.Println("")
+		fmt.Println("--------------------------------------------------------------------------------")
+		debug.PrintStack()
+		fmt.Println("--------------------------------------------------------------------------------")
+	} else {
+		fmt.Println("The stack trace has been saved to", traceFile)
+		fmt.Println("")
+		fmt.Println("You can file an issue at https://github.com/tulir/gomuks/issues.")
+		fmt.Println("Please provide the contents of that file when filing an issue.")
+	}
+	os.Exit(1)
+}

ui/view-main.go

@@ -148,7 +148,7 @@ func (view *MainView) InputDone(key tcell.Key) {
 }
 
 func (view *MainView) HandleCommand(room, command string, args []string) {
-	view.gmx.Recover()
+	defer view.gmx.Recover()
 	debug.Print("Handling command", command, args)
 	switch command {
 	case "/quit":
@@ -156,6 +156,8 @@ func (view *MainView) HandleCommand(room, command string, args []string) {
 	case "/clearcache":
 		view.config.Session.Clear()
 		view.gmx.Stop()
+	case "/panic":
+		panic("This is a test panic.")
 	case "/part":
 		fallthrough
 	case "/leave":