fix(imap): fix parsing of optional date in APPEND command

The parser failed when the optional date was provided

Refs: #948

Author: marle3003

imap/append.go

@@ -5,7 +5,6 @@ import (
 	"bytes"
 	"encoding/base64"
 	"fmt"
-	log "github.com/sirupsen/logrus"
 	"io"
 	"mime/multipart"
 	"mime/quotedprintable"
@@ -15,6 +14,8 @@ import (
 	"net/textproto"
 	"strings"
 	"time"
+
+	log "github.com/sirupsen/logrus"
 )
 
 type AppendOptions struct {
@@ -36,7 +37,7 @@ func (c *conn) handleAppend(tag string, d *Decoder) error {
 	}
 	d.SP()
 
-	opt := AppendOptions{}
+	opt := AppendOptions{Date: time.Now()}
 	if d.IsList() {
 		err = d.List(func() error {
 			f, err := d.ReadFlag()
@@ -52,6 +53,14 @@ func (c *conn) handleAppend(tag string, d *Decoder) error {
 		d.SP()
 	}
 
+	if d.is("\"") {
+		opt.Date, err = d.Date()
+		if err != nil {
+			return err
+		}
+		d.SP()
+	}
+
 	if err := d.expect("{"); err != nil {
 		return err
 	}
@@ -63,7 +72,7 @@ func (c *conn) handleAppend(tag string, d *Decoder) error {
 		return err
 	}
 
-	c.tpc.PrintfLine("+ Ready for literal data")
+	_ = c.tpc.PrintfLine("+ Ready for literal data")
 
 	r := io.LimitReader(c.tpc.R, size)
 	data, err := io.ReadAll(r)

imap/append_test.go

@@ -2,12 +2,14 @@ package imap_test
 
 import (
 	"fmt"
-	"github.com/stretchr/testify/require"
 	"mokapi/imap"
 	"mokapi/imap/imaptest"
 	"mokapi/smtp"
 	"mokapi/try"
 	"testing"
+	"time"
+
+	"github.com/stretchr/testify/require"
 )
 
 func TestAppend(t *testing.T) {
@@ -37,7 +39,7 @@ func TestAppend(t *testing.T) {
 	}()
 
 	c := imap.NewClient(fmt.Sprintf("localhost:%v", p))
-	defer c.Close()
+	defer func() { _ = c.Close() }()
 
 	_, err := c.Dial()
 	require.NoError(t, err)
@@ -73,6 +75,7 @@ func TestAppend_Flags(t *testing.T) {
 	handler := &imaptest.Handler{
 		AppendFunc: func(mailbox string, msg *smtp.Message, opt imap.AppendOptions) error {
 			require.Equal(t, []imap.Flag{imap.FlagSeen}, opt.Flags)
+			require.Greater(t, opt.Date, time.Time{})
 			return nil
 		},
 	}
@@ -89,7 +92,7 @@ func TestAppend_Flags(t *testing.T) {
 	}()
 
 	c := imap.NewClient(fmt.Sprintf("localhost:%v", p))
-	defer c.Close()
+	defer func() { _ = c.Close() }()
 
 	_, err := c.Dial()
 	require.NoError(t, err)
@@ -119,3 +122,56 @@ func TestAppend_Flags(t *testing.T) {
 	require.Equal(t, "A003 OK APPEND completed", res2)
 
 }
+
+func TestAppend_Flags_And_Time(t *testing.T) {
+
+	handler := &imaptest.Handler{
+		AppendFunc: func(mailbox string, msg *smtp.Message, opt imap.AppendOptions) error {
+			require.Equal(t, []imap.Flag{imap.FlagSeen}, opt.Flags)
+			require.Equal(t, "2026-04-26T14:20:31+02:00", opt.Date.Format(time.RFC3339))
+			return nil
+		},
+	}
+
+	p := try.GetFreePort()
+	s := &imap.Server{
+		Addr:    fmt.Sprintf(":%v", p),
+		Handler: handler,
+	}
+	defer s.Close()
+	go func() {
+		err := s.ListenAndServe()
+		require.ErrorIs(t, err, imap.ErrServerClosed)
+	}()
+
+	c := imap.NewClient(fmt.Sprintf("localhost:%v", p))
+	defer func() { _ = c.Close() }()
+
+	_, err := c.Dial()
+	require.NoError(t, err)
+
+	err = c.PlainAuth("", "", "")
+	require.NoError(t, err)
+
+	res, err := c.SendRaw("A003 APPEND Sent (\\Seen) \"26-Apr-2026 14:20:31 +0200\" {310}")
+	require.NoError(t, err)
+	require.Equal(t, "+ Ready for literal data", res)
+
+	request := []string{
+		"Date: Mon, 7 Feb 1994 21:52:25 -0800 (PST)",
+		"From: Fred Foobar <foobar@Blurdybloop.COM>",
+		"Subject: afternoon meeting",
+		"To: mooch@owatagu.siam.edu",
+		"Message-Id: <B27397-0100000@Blurdybloop.COM>",
+		"MIME-Version: 1.0",
+		"Content-Type: TEXT/PLAIN; CHARSET=US-ASCII",
+		"",
+		"Hello Joe, do you think we can meet at 3:30 tomorrow?",
+		"",
+	}
+
+	res2, err := c.SendRawLines(request)
+	require.NoError(t, err)
+	require.Equal(t, "A003 OK APPEND completed", res2)
+
+}