Do not allow to save drafts in non-writeable chats, fix #1986 (#1997)

python/src/deltachat/chat.py

@@ -82,6 +82,14 @@ class Chat(object):
         """
         return not lib.dc_chat_is_unpromoted(self._dc_chat)
 
+    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
+
+        :returns: True if the chat is writable, False otherwise
+        """
+        return lib.dc_chat_can_send(self._dc_chat)
+
     def is_protected(self):
         """ return True if this chat is a protected chat.
 

python/tests/test_account.py

@@ -1032,6 +1032,16 @@ class TestOnlineAccount:
         assert msg_in.text == text2
         assert ac1.get_config("addr") in [x.addr for x in msg_in.chat.get_contacts()]
 
+    def test_no_draft_if_cant_send(self, acfactory):
+        """Tests that no quote can be set if the user can't send to this chat"""
+        ac1 = acfactory.get_one_online_account()
+        device_chat = ac1.get_device_chat()
+        msg = Message.new_empty(ac1, "text")
+        device_chat.set_draft(msg)
+
+        assert not device_chat.can_send()
+        assert device_chat.get_draft() is None
+
     def test_prefer_encrypt(self, acfactory, lp):
         """Test quorum rule for encryption preference in 1:1 and group chat."""
         ac1, ac2, ac3 = acfactory.get_many_online_accounts(3)

src/chat.rs

@@ -460,6 +460,12 @@ impl ChatId {
                 msg.param.set(Param::File, blob.as_name());
             }
         }
+
+        let chat = Chat::load_from_db(context, self).await?;
+        if !chat.can_send() {
+            bail!("Can't set a draft: Can't send");
+        }
+
         context
             .sql
             .execute(