aerc: always check SelectedAccount return value

aerc.SelectedAccount() is used in lots of places. Most of them without
checking the return value.

In some cases, the currently selected tab is not related to any account
(widget.Terminal for example). This can lead to unexpected crashes when
accessing account specific configuration.

When possible, return an error when no account is currently selected.
If no error can be returned, fallback to non-account specific
configuration.

Signed-off-by: Robin Jarry <robin@jarry.cc>
Reviewed-by: Koni Marti <koni.marti@gmail.com>

commands/account/compose.go

@@ -30,6 +30,9 @@ func (Compose) Execute(aerc *widgets.Aerc, args []string) error {
 		return err
 	}
 	acct := aerc.SelectedAccount()
+	if acct == nil {
+		return errors.New("No account selected")
+	}
 	if template == "" {
 		template = aerc.Config().Templates.NewMessage
 	}

commands/account/view.go

@@ -26,6 +26,9 @@ func (ViewMessage) Execute(aerc *widgets.Aerc, args []string) error {
 		return errors.New("Usage: view-message")
 	}
 	acct := aerc.SelectedAccount()
+	if acct == nil {
+		return errors.New("No account selected")
+	}
 	if acct.Messages().Empty() {
 		return nil
 	}

commands/commands.go

@@ -117,11 +117,15 @@ func (cmds *Commands) GetCompletions(aerc *widgets.Aerc, cmd string) []string {
 
 func GetFolders(aerc *widgets.Aerc, args []string) []string {
 	out := make([]string, 0)
-	if len(args) == 0 {
+	acct := aerc.SelectedAccount()
-		return aerc.SelectedAccount().Directories().List()
+	if acct == nil {
+		return out
 	}
-	for _, dir := range aerc.SelectedAccount().Directories().List() {
+	if len(args) == 0 {
-		if foundInString(dir, args[0], aerc.SelectedAccount().UiConfig().FuzzyFolderComplete) {
+		return acct.Directories().List()
+	}
+	for _, dir := range acct.Directories().List() {
+		if foundInString(dir, args[0], acct.UiConfig().FuzzyFolderComplete) {
 			out = append(out, dir)
 		}
 	}
@@ -144,8 +148,12 @@ func CompletionFromList(valid []string, args []string) []string {
 }
 
 func GetLabels(aerc *widgets.Aerc, args []string) []string {
+	acct := aerc.SelectedAccount()
+	if acct == nil {
+		return make([]string, 0)
+	}
 	if len(args) == 0 {
-		return aerc.SelectedAccount().Labels()
+		return acct.Labels()
 	}
 
 	// + and - are used to denote tag addition / removal and need to be striped
@@ -165,7 +173,7 @@ func GetLabels(aerc *widgets.Aerc, args []string) []string {
 	trimmed := strings.TrimLeft(last, "+-")
 
 	out := make([]string, 0)
-	for _, label := range aerc.SelectedAccount().Labels() {
+	for _, label := range acct.Labels() {
 		if hasCaseSmartPrefix(label, trimmed) {
 			var prev string
 			if len(others) > 0 {

commands/compose/postpone.go

@@ -31,6 +31,10 @@ func (Postpone) Execute(aerc *widgets.Aerc, args []string) error {
 	if len(args) != 1 {
 		return errors.New("Usage: postpone")
 	}
+	acct := aerc.SelectedAccount()
+	if acct == nil {
+		return errors.New("No account selected")
+	}
 	composer, _ := aerc.SelectedTab().(*widgets.Composer)
 	config := composer.Config()
 	tabName := aerc.TabNames()[aerc.SelectedTabIndex()]
@@ -48,7 +52,7 @@ func (Postpone) Execute(aerc *widgets.Aerc, args []string) error {
 	header.SetContentType("text/plain", map[string]string{"charset": "UTF-8"})
 	header.Set("Content-Transfer-Encoding", "quoted-printable")
 	worker := composer.Worker()
-	dirs := aerc.SelectedAccount().Directories().List()
+	dirs := acct.Directories().List()
 	alreadyCreated := false
 	for _, dir := range dirs {
 		if dir == config.Postpone {

commands/msg/unsubscribe.go

@@ -89,6 +89,9 @@ func parseUnsubscribeMethods(header string) (methods []*url.URL) {
 func unsubscribeMailto(aerc *widgets.Aerc, u *url.URL) error {
 	widget := aerc.SelectedTab().(widgets.ProvidesMessage)
 	acct := widget.SelectedAccount()
+	if acct == nil {
+		return errors.New("No account selected")
+	}
 
 	h := &mail.Header{}
 	h.SetSubject(u.Query().Get("subject"))

commands/msgview/next.go

@@ -1,6 +1,8 @@
 package msgview
 
 import (
+	"errors"
+
 	"git.sr.ht/~rjarry/aerc/commands/account"
 	"git.sr.ht/~rjarry/aerc/lib"
 	"git.sr.ht/~rjarry/aerc/widgets"
@@ -27,6 +29,9 @@ func (NextPrevMsg) Execute(aerc *widgets.Aerc, args []string) error {
 	}
 	mv, _ := aerc.SelectedTab().(*widgets.MessageViewer)
 	acct := mv.SelectedAccount()
+	if acct == nil {
+		return errors.New("No account selected")
+	}
 	store := mv.Store()
 	err = account.ExecuteNextPrevMessage(args, acct, pct, n)
 	if err != nil {

widgets/aerc.go

@@ -309,6 +309,14 @@ func (aerc *Aerc) SelectedAccount() *AccountView {
 	return nil
 }
 
+func (aerc *Aerc) SelectedAccountUiConfig() config.UIConfig {
+	acct := aerc.SelectedAccount()
+	if acct == nil {
+		return aerc.conf.Ui
+	}
+	return acct.UiConfig()
+}
+
 func (aerc *Aerc) SelectedTab() ui.Drawable {
 	return aerc.tabs.Tabs[aerc.tabs.Selected].Content
 }

widgets/compose.go

@@ -127,15 +127,15 @@ func (c *Composer) buildComposeHeader(aerc *Aerc, cmpl *completer.Completer) {
 	c.layout = aerc.conf.Compose.HeaderLayout
 	c.editors = make(map[string]*headerEditor)
 	c.focusable = make([]ui.MouseableDrawableInteractive, 0)
+	uiConfig := aerc.SelectedAccountUiConfig()
 
 	for i, row := range c.layout {
 		for j, h := range row {
 			h = strings.ToLower(h)
 			c.layout[i][j] = h // normalize to lowercase
-			e := newHeaderEditor(h, c.header, aerc.SelectedAccount().UiConfig())
+			e := newHeaderEditor(h, c.header, uiConfig)
 			if aerc.conf.Ui.CompletionPopovers {
-				e.input.TabComplete(cmpl.ForHeader(h),
+				e.input.TabComplete(cmpl.ForHeader(h), uiConfig.CompletionDelay)
-					aerc.SelectedAccount().UiConfig().CompletionDelay)
 			}
 			c.editors[h] = e
 			switch h {
@@ -152,9 +152,9 @@ func (c *Composer) buildComposeHeader(aerc *Aerc, cmpl *completer.Completer) {
 	for _, h := range []string{"cc", "bcc"} {
 		if c.header.Has(h) {
 			if _, ok := c.editors[h]; !ok {
-				e := newHeaderEditor(h, c.header, aerc.SelectedAccount().UiConfig())
+				e := newHeaderEditor(h, c.header, uiConfig)
 				if aerc.conf.Ui.CompletionPopovers {
-					e.input.TabComplete(cmpl.ForHeader(h), aerc.SelectedAccount().UiConfig().CompletionDelay)
+					e.input.TabComplete(cmpl.ForHeader(h), uiConfig.CompletionDelay)
 				}
 				c.editors[h] = e
 				c.focusable = append(c.focusable, e)
@@ -741,11 +741,10 @@ func (c *Composer) AddEditor(header string, value string, appendHeader bool) {
 		e.storeValue() // flush modifications from the user to the header
 		editor = e
 	} else {
-		e := newHeaderEditor(header, c.header,
+		uiConfig := c.aerc.SelectedAccountUiConfig()
-			c.aerc.SelectedAccount().UiConfig())
+		e := newHeaderEditor(header, c.header, uiConfig)
-		if c.config.Ui.CompletionPopovers {
+		if uiConfig.CompletionPopovers {
-			e.input.TabComplete(c.completer.ForHeader(header),
+			e.input.TabComplete(c.completer.ForHeader(header), uiConfig.CompletionDelay)
-				c.config.Ui.CompletionDelay)
 		}
 		c.editors[header] = e
 		c.layout = append(c.layout, []string{header})

widgets/msglist.go

@@ -53,11 +53,13 @@ func (ml *MessageList) Invalidate() {
 
 func (ml *MessageList) Draw(ctx *ui.Context) {
 	ml.height = ctx.Height()
+	uiConfig := ml.aerc.SelectedAccountUiConfig()
 	ctx.Fill(0, 0, ctx.Width(), ctx.Height(), ' ',
-		ml.aerc.SelectedAccount().UiConfig().GetStyle(config.STYLE_MSGLIST_DEFAULT))
+		uiConfig.GetStyle(config.STYLE_MSGLIST_DEFAULT))
 
+	acct := ml.aerc.SelectedAccount()
 	store := ml.Store()
-	if store == nil {
+	if store == nil || acct == nil {
 		if ml.isInitalizing {
 			ml.spinner.Draw(ctx)
 			return
@@ -89,7 +91,7 @@ func (ml *MessageList) Draw(ctx *ui.Context) {
 		row          int = 0
 	)
 
-	if ml.aerc.SelectedAccount().UiConfig().ThreadingEnabled || store.BuildThreads() {
+	if uiConfig.ThreadingEnabled || store.BuildThreads() {
 		threads := store.Threads
 		counter := len(store.Uids())
 
@@ -119,8 +121,8 @@ func (ml *MessageList) Draw(ctx *ui.Context) {
 					}
 				}
 				fmtCtx := format.Ctx{
-					FromAddress:       ml.aerc.SelectedAccount().acct.From,
+					FromAddress:       acct.acct.From,
-					AccountName:       ml.aerc.SelectedAccount().Name(),
+					AccountName:       acct.Name(),
 					MsgInfo:           msg,
 					MsgNum:            row,
 					MsgIsMarked:       store.IsMarked(t.Uid),
@@ -144,8 +146,8 @@ func (ml *MessageList) Draw(ctx *ui.Context) {
 			uid := uids[i]
 			msg := store.Messages[uid]
 			fmtCtx := format.Ctx{
-				FromAddress: ml.aerc.SelectedAccount().acct.From,
+				FromAddress: acct.acct.From,
-				AccountName: ml.aerc.SelectedAccount().Name(),
+				AccountName: acct.Name(),
 				MsgInfo:     msg,
 				MsgNum:      row,
 				MsgIsMarked: store.IsMarked(uid),
@@ -183,8 +185,9 @@ func (ml *MessageList) Draw(ctx *ui.Context) {
 func (ml *MessageList) drawRow(textWidth int, ctx *ui.Context, uid uint32, row int, needsHeaders *[]uint32, fmtCtx format.Ctx) bool {
 	store := ml.store
 	msg := store.Messages[uid]
+	acct := ml.aerc.SelectedAccount()
 
-	if row >= ctx.Height() {
+	if row >= ctx.Height() || acct == nil {
 		return true
 	}
 
@@ -195,8 +198,8 @@ func (ml *MessageList) drawRow(textWidth int, ctx *ui.Context, uid uint32, row i
 	}
 
 	confParams := map[config.ContextType]string{
-		config.UI_CONTEXT_ACCOUNT: ml.aerc.SelectedAccount().AccountConfig().Name,
+		config.UI_CONTEXT_ACCOUNT: acct.AccountConfig().Name,
-		config.UI_CONTEXT_FOLDER:  ml.aerc.SelectedAccount().Directories().Selected(),
+		config.UI_CONTEXT_FOLDER:  acct.Directories().Selected(),
 	}
 	if msg.Envelope != nil {
 		confParams[config.UI_CONTEXT_SUBJECT] = msg.Envelope.Subject
@@ -288,7 +291,7 @@ func (ml *MessageList) MouseEvent(localX int, localY int, event tcell.Event) {
 			if ok {
 				ml.Select(selectedMsg)
 				acct := ml.aerc.SelectedAccount()
-				if acct.Messages().Empty() {
+				if acct == nil || acct.Messages().Empty() {
 					return
 				}
 				store := acct.Messages().Store()
@@ -433,7 +436,7 @@ func (ml *MessageList) ensureScroll() {
 }
 
 func (ml *MessageList) drawEmptyMessage(ctx *ui.Context) {
-	uiConfig := ml.aerc.SelectedAccount().UiConfig()
+	uiConfig := ml.aerc.SelectedAccountUiConfig()
 	msg := uiConfig.EmptyMessage
 	ctx.Printf((ctx.Width()/2)-(len(msg)/2), 0,
 		uiConfig.GetStyle(config.STYLE_MSGLIST_DEFAULT), "%s", msg)