imap: expunge folder before IDLE if needed

This ensures Inbox is expunged timely in setups that don't watch
DeltaChat folder.

python/tests/test_account.py

@@ -1542,7 +1542,6 @@ class TestOnlineAccount:
         assert msg.is_encrypted(), "Message is not encrypted"
         assert msg.chat == ac2.create_chat(ac4)
 
-    @pytest.mark.xfail
     def test_immediate_autodelete(self, acfactory, lp):
         ac1 = acfactory.get_online_configuring_account()
         ac2 = acfactory.get_online_configuring_account(mvbox=False, move=False, sentbox=False)

src/imap/select_folder.rs

@@ -51,6 +51,14 @@ impl Imap {
         Ok(())
     }
 
+    /// Issues a CLOSE command if selected folder needs expunge.
+    pub(crate) async fn maybe_close_folder(&mut self, context: &Context) -> Result<()> {
+        if self.config.selected_folder_needs_expunge {
+            self.close_folder(context).await?;
+        }
+        Ok(())
+    }
+
     /// select a folder, possibly update uid_validity and, if needed,
     /// expunge the folder to remove delete-marked messages.
     pub(super) async fn select_folder<S: AsRef<str>>(
@@ -76,10 +84,7 @@ impl Imap {
         }
 
         // deselect existing folder, if needed (it's also done implicitly by SELECT, however, without EXPUNGE then)
-        let needs_expunge = { self.config.selected_folder_needs_expunge };
+        self.maybe_close_folder(context).await?;
-        if needs_expunge {
-            self.close_folder(context).await?;
-        }
 
         // select new folder
         if let Some(ref folder) = folder {

src/scheduler.rs

@@ -74,6 +74,13 @@ async fn inbox_loop(ctx: Context, started: Sender<()>, inbox_handlers: ImapConne
                 }
                 None => {
                     jobs_loaded = 0;
+
+                    // Expunge folder if needed, e.g. if some jobs have
+                    // deleted messages on the server.
+                    if let Err(err) = connection.maybe_close_folder(&ctx).await {
+                        warn!(ctx, "failed to close folder: {:?}", err);
+                    }
+
                     info = if ctx.get_config_bool(Config::InboxWatch).await {
                         fetch_idle(&ctx, &mut connection, Config::ConfiguredInboxFolder).await
                     } else {