refactor: Make MvboxMove a dependent setting of IsChatmail

This makes the code more straightforward in some places and also allows to keep `MvboxMove` unset
for chatmail case and thus know that the user hasn't modified it.

src/config.rs

@@ -164,7 +164,6 @@ pub enum Config {
 
     /// True if chat messages should be moved to a separate folder. Auto-sent messages like sync
     /// ones are moved there anyway.
-    #[strum(props(default = "1"))]
     MvboxMove,
 
     /// Watch for new messages in the "Mvbox" (aka DeltaChat folder) only.
@@ -596,9 +595,17 @@ impl Context {
             .unwrap_or_default())
     }
 
+    /// Returns true if chat messages should be moved to the mvbox ("DeltaChat" folder).
+    pub(crate) async fn should_move_to_mvbox(&self) -> Result<bool> {
+        match self.get_config_bool_opt(Config::MvboxMove).await? {
+            Some(val) => Ok(val),
+            None => Ok(!self.get_config_bool(Config::IsChatmail).await?),
+        }
+    }
+
     /// Returns true if movebox ("DeltaChat" folder) should be watched.
     pub(crate) async fn should_watch_mvbox(&self) -> Result<bool> {
-        Ok(self.get_config_bool(Config::MvboxMove).await?
+        Ok(self.should_move_to_mvbox().await?
             || self.get_config_bool(Config::OnlyFetchMvbox).await?
             || !self.get_config_bool(Config::IsChatmail).await?)
     }

src/config/config_tests.rs

@@ -185,6 +185,15 @@ async fn test_delete_server_after_default() -> Result<()> {
     Ok(())
 }
 
+#[tokio::test(flavor = "multi_thread", worker_threads = 2)]
+async fn test_should_move_to_mvbox() -> Result<()> {
+    let alice = &TestContext::new_alice().await;
+    assert!(alice.should_move_to_mvbox().await?);
+    alice.set_config_bool(Config::IsChatmail, true).await?;
+    assert!(!alice.should_move_to_mvbox().await?);
+    Ok(())
+}
+
 const SAVED_MESSAGES_DEDUPLICATED_FILE: &str = "969142cb84015bc135767bc2370934a.png";
 
 #[tokio::test(flavor = "multi_thread", worker_threads = 2)]

src/configure.rs

@@ -529,7 +529,6 @@ async fn configure(ctx: &Context, param: &EnteredLoginParam) -> Result<Configure
     };
     if is_chatmail {
         ctx.set_config(Config::SentboxWatch, None).await?;
-        ctx.set_config(Config::MvboxMove, Some("0")).await?;
         ctx.set_config(Config::OnlyFetchMvbox, None).await?;
         ctx.set_config(Config::ShowEmails, None).await?;
     }

src/imap.rs

@@ -482,7 +482,10 @@ impl Imap {
                 false => session.is_chatmail(),
                 true => context.get_config_bool(Config::IsChatmail).await?,
             };
-            let create_mvbox = !is_chatmail || context.get_config_bool(Config::MvboxMove).await?;
+            let create_mvbox = context
+                .get_config_bool_opt(Config::MvboxMove)
+                .await?
+                .unwrap_or(!is_chatmail);
             self.configure_folders(context, &mut session, create_mvbox)
                 .await?;
         }
@@ -1784,7 +1787,7 @@ impl Imap {
             context
                 .set_config_internal(Config::ConfiguredMvboxFolder, Some(mvbox_folder))
                 .await?;
-        } else if create_mvbox && context.config_exists(Config::MvboxMove).await? {
+        } else if context.get_config_bool_opt(Config::MvboxMove).await? == Some(true) {
             warn!(context, "Will retry configuring MVBOX on reconnect.");
             return Ok(());
         }
@@ -1997,7 +2000,7 @@ async fn needs_move_to_mvbox(
             }
         }
     }
-    if !context.get_config_bool(Config::MvboxMove).await? {
+    if !context.should_move_to_mvbox().await? {
         return Ok(false);
     }