Optionally pass disabled commands on to next handler

If a DisabledReason has its AllowFurtherDispatching flag set, it is returned as
a ErrKeybindingNotHandled error, instead of shown as a toast right away. This
allows gocui to continue to dispatch the keybinding, and we can unwrap the error
at the other end (in our global ErrorHandler) and display it then.

This allows having keybindings for the same key at the local and global levels,
and they will continue to be dispatched even if the first one returns a
DisabledReason. It is opt-in, so we only use it for cases where we know that a
local and a global handler share the same (default) keybinding.

pkg/gui/keybindings.go

@@ -525,6 +525,10 @@ func (gui *Gui) SetMouseKeybinding(binding *gocui.ViewMouseBinding) error {
 func (gui *Gui) callKeybindingHandler(binding *types.Binding) error {
 	if binding.GetDisabledReason != nil {
 		if disabledReason := binding.GetDisabledReason(); disabledReason != nil {
+			if disabledReason.AllowFurtherDispatching {
+				return &types.ErrKeybindingNotHandled{DisabledReason: disabledReason}
+			}
+
 			if disabledReason.ShowErrorInPanel {
 				return errors.New(disabledReason.Text)
 			}

pkg/gui/popup/popup_handler.go

@@ -2,6 +2,7 @@ package popup
 
 import (
 	"context"
+	"errors"
 	"strings"
 
 	"github.com/jesseduffield/gocui"
@@ -80,6 +81,16 @@ func (self *PopupHandler) WithWaitingStatusSync(message string, f func() error)
 }
 
 func (self *PopupHandler) ErrorHandler(err error) error {
+	var notHandledError *types.ErrKeybindingNotHandled
+	if errors.As(err, &notHandledError) {
+		if !notHandledError.DisabledReason.ShowErrorInPanel {
+			if msg := notHandledError.DisabledReason.Text; len(msg) > 0 {
+				self.ErrorToast(self.Tr.DisabledMenuItemPrefix + msg)
+			}
+			return nil
+		}
+	}
+
 	// Need to set bold here explicitly; otherwise it gets cancelled by the red colouring.
 	coloredMessage := style.FgRed.SetBold().Sprint(strings.TrimSpace(err.Error()))
 	if err := self.onErrorFn(); err != nil {

pkg/gui/types/common.go

@@ -202,6 +202,10 @@ type DisabledReason struct {
 	// error panel instead. This is useful if the text is very long, or if it is
 	// important enough to show it more prominently, or both.
 	ShowErrorInPanel bool
+
+	// If true, the keybinding dispatch mechanism will continue to look for
+	// other handlers for the keypress.
+	AllowFurtherDispatching bool
 }
 
 type MenuWidget int

pkg/gui/types/keybindings.go

@@ -55,3 +55,15 @@ type KeybindingGuards struct {
 	OutsideFilterMode Guard
 	NoPopupPanel      Guard
 }
+
+type ErrKeybindingNotHandled struct {
+	DisabledReason *DisabledReason
+}
+
+func (e ErrKeybindingNotHandled) Error() string {
+	return e.DisabledReason.Text
+}
+
+func (e ErrKeybindingNotHandled) Unwrap() error {
+	return gocui.ErrKeybindingNotHandled
+}