Close connection before deleting labels to prevent panics accessing deleted bucket

internal/store/mailbox.go

@@ -38,6 +38,8 @@ type Mailbox struct {
 	color       string
 
 	log *logrus.Entry
+
+	isDeleting bool
 }
 
 func newMailbox(storeAddress *Address, labelID, labelPrefix, labelName, color string) (mb *Mailbox, err error) {
@@ -215,6 +217,7 @@ func (storeMailbox *Mailbox) Rename(newName string) error {
 // Deletion has to be propagated to all the same mailboxes in all addresses.
 // The propagation is processed by the event loop.
 func (storeMailbox *Mailbox) Delete() error {
+	storeMailbox.isDeleting = true
 	return storeMailbox.storeAddress.deleteMailbox(storeMailbox.labelID)
 }
 
@@ -226,6 +229,14 @@ func (storeMailbox *Mailbox) GetDelimiter() string {
 // deleteMailboxEvent deletes the mailbox bucket.
 // This is called from the event loop.
 func (storeMailbox *Mailbox) deleteMailboxEvent() error {
+	if !storeMailbox.isDeleting {
+		// Deleting label removes bucket. Any ongoing connection selected
+		// in such mailbox then might panic because of non-existing bucket.
+		// Closing connetions prevents that panic but if the connection
+		// asked for deletion, it should not be closed so it can receive
+		// successful response.
+		storeMailbox.store.user.CloseAllConnections()
+	}
 	return storeMailbox.db().Update(func(tx *bolt.Tx) error {
 		return tx.Bucket(mailboxesBucket).DeleteBucket(storeMailbox.getBucketName())
 	})

internal/store/mocks/mocks.go

@@ -106,6 +106,18 @@ func (m *MockBridgeUser) EXPECT() *MockBridgeUserMockRecorder {
 	return m.recorder
 }
 
+// CloseAllConnections mocks base method
+func (m *MockBridgeUser) CloseAllConnections() {
+	m.ctrl.T.Helper()
+	m.ctrl.Call(m, "CloseAllConnections")
+}
+
+// CloseAllConnections indicates an expected call of CloseAllConnections
+func (mr *MockBridgeUserMockRecorder) CloseAllConnections() *gomock.Call {
+	mr.mock.ctrl.T.Helper()
+	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "CloseAllConnections", reflect.TypeOf((*MockBridgeUser)(nil).CloseAllConnections))
+}
+
 // CloseConnection mocks base method
 func (m *MockBridgeUser) CloseConnection(arg0 string) {
 	m.ctrl.T.Helper()

internal/store/types.go

@@ -36,6 +36,7 @@ type BridgeUser interface {
 	GetPrimaryAddress() string
 	GetStoreAddresses() []string
 	UpdateUser() error
+	CloseAllConnections()
 	CloseConnection(string)
 	Logout() error
 }