Remove deaddrop chat

Contact request chats are not merged into a single virtual "deaddrop"
chat anymore. Instead, they are shown in the chatlist the same way as
other chats, but sending of messages to them is not allowed and MDNs
are not sent automatically until the chat is "accepted" by the user.

New API:
- dc_chat_is_contact_request(): returns true if chat is a contact
request.  In this case option to accept and block the chat via
dc_accept_chat() and dc_block_chat() should be shown in the UI.
- dc_accept_chat(): accept contact request and unblock the chat
- dc_block_chat(): decline contact request and block the chat

Removed API:
- dc_create_chat_by_msg_id(): deprecated 2021-02-07 in favor of
  dc_decide_on_contact_request()
- dc_marknoticed_contact(): deprecated 2021-02-07 in favor of
  dc_decide_on_contact_request()
- dc_decide_on_contact_request(): this call requires a message ID from
  deaddrop chat as input. As deaddrop chat is removed, this call can't
  be used anymore.
- dc_msg_get_real_chat_id(): use dc_msg_get_chat_id() instead, the
  only difference between these calls was in handling of deaddrop chat
- removed DC_CHAT_ID_DEADDROP and DC_STR_DEADDROP constants

python/src/deltachat/account.py

@@ -330,9 +330,6 @@ class Account(object):
         """ Create a 1:1 chat with Account, Contact or e-mail address. """
         return self.create_contact(obj).create_chat()
 
-    def _create_chat_by_message_id(self, msg_id):
-        return Chat(self, lib.dc_create_chat_by_msg_id(self._dc_context, msg_id))
-
     def create_group_chat(self, name, contacts=None, verified=False):
         """ create a new group chat object.
 
@@ -367,9 +364,6 @@ class Account(object):
             chatlist.append(Chat(self, chat_id))
         return chatlist
 
-    def get_deaddrop_chat(self):
-        return Chat(self, const.DC_CHAT_ID_DEADDROP)
-
     def get_device_chat(self):
         return Contact(self, const.DC_CONTACT_ID_DEVICE).create_chat()
 

python/src/deltachat/chat.py

@@ -50,6 +50,14 @@ class Chat(object):
         """
         lib.dc_delete_chat(self.account._dc_context, self.id)
 
+    def block(self):
+        """Block this chat."""
+        lib.dc_block_chat(self.account._dc_context, self.id)
+
+    def accept(self):
+        """Accept this contact request chat."""
+        lib.dc_accept_chat(self.account._dc_context, self.id)
+
     # ------  chat status/metadata API ------------------------------
 
     def is_group(self):
@@ -59,13 +67,6 @@ class Chat(object):
         """
         return lib.dc_chat_get_type(self._dc_chat) == const.DC_CHAT_TYPE_GROUP
 
-    def is_deaddrop(self):
-        """ return true if this chat is a deaddrop chat.
-
-        :returns: True if chat is the deaddrop chat, False otherwise.
-        """
-        return self.id == const.DC_CHAT_ID_DEADDROP
-
     def is_muted(self):
         """ return true if this chat is muted.
 
@@ -73,6 +74,13 @@ class Chat(object):
         """
         return lib.dc_chat_is_muted(self._dc_chat)
 
+    def is_contact_request(self):
+        """ return True if this chat is a contact request chat.
+
+        :returns: True if chat is a contact request chat, False otherwise.
+        """
+        return lib.dc_chat_is_contact_request(self._dc_chat)
+
     def is_promoted(self):
         """ return True if this chat is promoted, i.e.
         the member contacts are aware of their membership,
@@ -84,7 +92,7 @@ class Chat(object):
 
     def can_send(self):
         """Check if messages can be sent to a give chat.
-        This is not true eg. for the deaddrop or for the device-talk
+        This is not true eg. for the contact requests or for the device-talk
 
         :returns: True if the chat is writable, False otherwise
         """

python/src/deltachat/hookspec.py

@@ -43,7 +43,7 @@ class PerAccount:
 
     @account_hookspec
     def ac_incoming_message(self, message):
-        """ Called on any incoming message (to deaddrop or chat). """
+        """ Called on any incoming message (both existing chats and contact requests). """
 
     @account_hookspec
     def ac_outgoing_message(self, message):

python/src/deltachat/message.py

@@ -61,16 +61,13 @@ class Message(object):
     def create_chat(self):
         """ create or get an existing chat (group) object for this message.
 
-        If the message is a deaddrop contact request
+        If the message is a contact request
         the sender will become an accepted contact.
 
         :returns: a :class:`deltachat.chat.Chat` object.
         """
-        from .chat import Chat
-        chat_id = lib.dc_create_chat_by_msg_id(self.account._dc_context, self.id)
-        ctx = self.account._dc_context
-        self._dc_msg = ffi.gc(lib.dc_get_msg(ctx, self.id), lib.dc_msg_unref)
-        return Chat(self.account, chat_id)
+        self.chat.accept()
+        return self.chat
 
     @props.with_doc
     def id(self):