feat: Don't mark messages as seen on IMAP if bcc_self=0 or bot=1

bcc_self=0 means that the user disabled it or it's a chatmail setup with the only device and w/o
backups. If a backup is made someday, old messages not marked as IMAP-seen aren't a problem and new
ones are marked as IMAP-seen.

For bots, particularly multi-device ones (which are a rare case), probably no sane logic can be
built on the "seen" message status. Moreover, if the user has additionally a bot that reads incoming
messages, it doesn't mean that the user doesn't want to read them too.

deltachat-rpc-client/tests/test_multidevice.py

@@ -79,7 +79,6 @@ def test_one_account_send_bcc_setting(acfactory, log, direct_imap):
 
     # now make sure we are sending message to ourselves too
     assert self_addr in ev.msg
-    assert self_addr in ev.msg
 
     # BCC-self messages are marked as seen by the sender device.
     while True:

python/tests/test_1_online.py

@@ -160,6 +160,7 @@ def test_html_message(acfactory, lp):
 
 def test_webxdc_message(acfactory, data, lp):
     ac1, ac2 = acfactory.get_online_accounts(2)
+    ac2.set_config("bcc_self", "1")
     chat = acfactory.get_accepted_chat(ac1, ac2)
 
     lp.sec("ac1: prepare and send text message to ac2")
@@ -362,6 +363,8 @@ def test_send_and_receive_message_markseen(acfactory, lp):
     # make DC's life harder wrt to encodings
     ac1.set_config("displayname", "ä name")
 
+    ac2.set_config("bcc_self", "1")
+
     # clear any fresh device messages
     ac1.get_device_chat().mark_noticed()
     ac2.get_device_chat().mark_noticed()
@@ -502,9 +505,8 @@ def test_mdn_asymmetric(acfactory, lp):
     chat = ac1.create_chat(ac2)
     ac2.create_chat(ac1)
 
-    # make sure mdns are enabled (usually enabled by default already)
-    ac1.set_config("mdns_enabled", "1")
-    ac2.set_config("mdns_enabled", "1")
+    ac1.set_config("bcc_self", "1")
+    ac2.set_config("bcc_self", "1")
 
     lp.sec("sending text message from ac1 to ac2")
     msg_out = chat.send_text("message1")

src/imap.rs

@@ -2096,6 +2096,11 @@ async fn mark_seen_by_uid(
 /// Schedule marking the message as Seen on IMAP by adding all known IMAP messages corresponding to
 /// the given Message-ID to `imap_markseen` table.
 pub(crate) async fn markseen_on_imap_table(context: &Context, message_id: &str) -> Result<()> {
+    if !context.get_config_bool(Config::BccSelf).await?
+        || context.get_config_bool(Config::Bot).await?
+    {
+        return Ok(());
+    }
     context
         .sql
         .execute(