logging: fix race condition in startup

If a panic occurs in one of the workers, it can happen after the UI was
initialised, but before the cleanup function has been registered. With
this the start of the worker loops is deferred until the cleanup routine
was registered.

Signed-off-by: Moritz Poldrack <git@moritz.sh>

4 files changed, 14 insertions, 7 deletions

diff --git a/aerc.go b/aerc.go
index aa82f98f..9d93a501 100644
--- a/aerc.go
+++ b/aerc.go
@@ -166,11 +166,13 @@ func main() {
 		ui   *libui.UI
 	)
 
+	deferLoop := make(chan struct{})
+
 	aerc = widgets.NewAerc(conf, logger, func(cmd []string) error {
 		return execCommand(aerc, ui, cmd)
 	}, func(cmd string) []string {
 		return getCompletions(aerc, cmd)
-	}, &commands.CmdHistory)
+	}, &commands.CmdHistory, deferLoop)
 
 	ui, err = libui.Initialize(aerc)
 	if err != nil {
@@ -180,6 +182,7 @@ func main() {
 	logging.UICleanup = func() {
 		ui.Close()
 	}
+	close(deferLoop)
 
 	if conf.Ui.MouseEnabled {
 		ui.EnableMouse()
diff --git a/widgets/account-wizard.go b/widgets/account-wizard.go
index 1645d457..42d14d17 100644
--- a/widgets/account-wizard.go
+++ b/widgets/account-wizard.go
@@ -535,7 +535,7 @@ func (wizard *AccountWizard) finish(tutorial bool) {
 	wizard.conf.Accounts = append(wizard.conf.Accounts, account)
 
 	view, err := NewAccountView(wizard.aerc, wizard.conf, &account,
-		wizard.aerc.logger, wizard.aerc)
+		wizard.aerc.logger, wizard.aerc, nil)
 	if err != nil {
 		wizard.aerc.NewTab(errorScreen(err.Error(), wizard.conf.Ui),
 			account.Name)
diff --git a/widgets/account.go b/widgets/account.go
index 55c4f550..3bf104bd 100644
--- a/widgets/account.go
+++ b/widgets/account.go
@@ -47,8 +47,8 @@ func (acct *AccountView) UiConfig() config.UIConfig {
 }
 
 func NewAccountView(aerc *Aerc, conf *config.AercConfig, acct *config.AccountConfig,
-	logger *log.Logger, host TabHost) (*AccountView, error) {
-
+	logger *log.Logger, host TabHost, deferLoop chan struct{},
+) (*AccountView, error) {
 	acctUiConf := conf.GetUiConfig(map[config.ContextType]string{
 		config.UI_CONTEXT_ACCOUNT: acct.Name,
 	})
@@ -90,6 +90,10 @@ func NewAccountView(aerc *Aerc, conf *config.AercConfig, acct *config.AccountCon
 	go func() {
 		defer logging.PanicHandler()
 
+		if deferLoop != nil {
+			<-deferLoop
+		}
+
 		worker.Backend.Run()
 	}()
 
diff --git a/widgets/aerc.go b/widgets/aerc.go
index c96932c4..db447e47 100644
--- a/widgets/aerc.go
+++ b/widgets/aerc.go
@@ -48,8 +48,8 @@ type Choice struct {
 
 func NewAerc(conf *config.AercConfig, logger *log.Logger,
 	cmd func(cmd []string) error, complete func(cmd string) []string,
-	cmdHistory lib.History) *Aerc {
-
+	cmdHistory lib.History, deferLoop chan struct{},
+) *Aerc {
 	tabs := ui.NewTabs(&conf.Ui)
 
 	statusbar := ui.NewStack(conf.Ui)
@@ -85,7 +85,7 @@ func NewAerc(conf *config.AercConfig, logger *log.Logger,
 	conf.Triggers.ExecuteCommand = cmd
 
 	for i, acct := range conf.Accounts {
-		view, err := NewAccountView(aerc, conf, &conf.Accounts[i], logger, aerc)
+		view, err := NewAccountView(aerc, conf, &conf.Accounts[i], logger, aerc, deferLoop)
 		if err != nil {
 			tabs.Add(errorScreen(err.Error(), conf.Ui), acct.Name)
 		} else {