fix: Do not recover messages if they exceed size limit

connector/connector.go

@@ -9,6 +9,7 @@ import (
 )
 
 var ErrOperationNotAllowed = errors.New("operation not allowed")
+var ErrMessageSizeExceedsLimits = errors.New("message size exceeds limits")
 
 // Connector connects the gluon server to a remote mail store.
 type Connector interface {

internal/state/mailbox.go

@@ -7,6 +7,7 @@ import (
 	"strings"
 	"time"
 
+	"github.com/ProtonMail/gluon/connector"
 	"github.com/ProtonMail/gluon/imap"
 	"github.com/ProtonMail/gluon/imap/command"
 	"github.com/ProtonMail/gluon/internal/db"
@@ -238,6 +239,11 @@ var ErrKnownRecoveredMessage = errors.New("known recovered message, possible dup
 func (m *Mailbox) Append(ctx context.Context, literal []byte, flags imap.FlagSet, date time.Time) (imap.UID, error) {
 	uid, err := m.AppendRegular(ctx, literal, flags, date)
 	if err != nil {
+		// Can't store messages that exceed size limits
+		if errors.Is(err, connector.ErrMessageSizeExceedsLimits) {
+			return uid, err
+		}
+
 		// Failed to append to mailbox attempt to insert into recovery mailbox.
 		knownMessage, recoverErr := db.WriteResult(ctx, m.state.db(), func(ctx context.Context, tx *ent.Tx) (bool, error) {
 			return m.state.actionCreateRecoveredMessage(ctx, tx, literal, flags, date)

tests/recovery_mailbox_test.go

@@ -270,6 +270,33 @@ func TestRecoveryMailboxOnlyReportsOnFirstDedupedMessage(t *testing.T) {
 	})
 }
 
+func TestRecoveryMailboxDoesNotStoreMessageWhichExceedLimit(t *testing.T) {
+	runOneToOneTestClientWithAuth(t, defaultServerOptions(t, withConnectorBuilder(&sizeExceededAppendConnectorBuilder{})), func(client *client.Client, s *testSession) {
+		{
+			status, err := client.Status(ids.GluonRecoveryMailboxName, []goimap.StatusItem{goimap.StatusMessages})
+			require.NoError(t, err)
+			require.Equal(t, uint32(0), status.Messages)
+		}
+
+		status, err := client.Select("INBOX", false)
+		require.NoError(t, err)
+		require.Equal(t, uint32(0), status.Messages)
+		require.Error(t, doAppendWithClientFromFile(t, client, "INBOX", "testdata/original.eml", time.Now()))
+		require.Error(t, doAppendWithClientFromFile(t, client, "INBOX", "testdata/duplicate.eml", time.Now()))
+
+		{
+			status, err := client.Status(ids.GluonRecoveryMailboxName, []goimap.StatusItem{goimap.StatusMessages})
+			require.NoError(t, err)
+			require.Equal(t, uint32(0), status.Messages)
+		}
+		{
+			status, err := client.Status("INBOX", []goimap.StatusItem{goimap.StatusMessages})
+			require.NoError(t, err)
+			require.Equal(t, uint32(0), status.Messages)
+		}
+	})
+}
+
 func TestRecoveryMBoxCanBeCopiedOutOfDedup(t *testing.T) {
 	runOneToOneTestClientWithAuth(t, defaultServerOptions(t, withConnectorBuilder(&recoveryDedupConnectorConnectorBuilder{})), func(client *client.Client, s *testSession) {
 		// Insert first message, fails.
@@ -524,3 +551,33 @@ func (failAppendLabelConnectorBuilder) New(usernames []string, password []byte,
 		Dummy: connector.NewDummy(usernames, password, period, flags, permFlags, attrs),
 	}
 }
+
+// failAppendLabelConnector simulate Create Message failures and also ensures that no calls to Add or Move can take place.
+type sizeExceededAppendConnector struct {
+	*connector.Dummy
+}
+
+func (r *sizeExceededAppendConnector) CreateMessage(
+	_ context.Context,
+	_ imap.MailboxID,
+	_ []byte,
+	_ imap.FlagSet,
+	_ time.Time) (imap.Message, []byte, error) {
+	return imap.Message{}, nil, fmt.Errorf("messsage to large: %w", connector.ErrMessageSizeExceedsLimits)
+}
+
+func (r *sizeExceededAppendConnector) AddMessagesToMailbox(
+	_ context.Context,
+	_ []imap.MessageID,
+	_ imap.MailboxID,
+) error {
+	return fmt.Errorf("messsage to large: %w", connector.ErrMessageSizeExceedsLimits)
+}
+
+type sizeExceededAppendConnectorBuilder struct{}
+
+func (sizeExceededAppendConnectorBuilder) New(usernames []string, password []byte, period time.Duration, flags, permFlags, attrs imap.FlagSet) Connector {
+	return &sizeExceededAppendConnector{
+		Dummy: connector.NewDummy(usernames, password, period, flags, permFlags, attrs),
+	}
+}