src/imap/attributes.rs

@@ -34,6 +34,12 @@ impl AttributesProxy {
         Self { attrs: fetch_attrs }
     }
 
+    pub fn is_enabling_condstore(&self) -> bool {
+        self.attrs.iter().any(|x| {
+            matches!(x, MessageDataItemName::ModSeq)
+        })
+    }
+
     pub fn need_body(&self) -> bool {
         self.attrs.iter().any(|x| {
             match x {

src/imap/command/examined.rs

@@ -91,14 +91,19 @@ impl<'a> ExaminedContext<'a> {
         uid: &bool,
     ) -> Result<(Response<'static>, flow::Transition)> {
         match self.mailbox.fetch(sequence_set, attributes, uid).await {
-            Ok(resp) => Ok((
+            Ok((resp, enable_condstore)) => {
+                if enable_condstore {
+                    self.client_capabilities.enable_condstore();
+                }
+                Ok((
                     Response::build()
                         .to_req(self.req)
                         .message("FETCH completed")
                         .set_body(resp)
                         .ok()?,
                     flow::Transition::None,
-            )),
+                ))
+            },
             Err(e) => Ok((
                 Response::build()
                     .to_req(self.req)

src/imap/command/selected.rs

@@ -117,14 +117,19 @@ impl<'a> SelectedContext<'a> {
         uid: &bool,
     ) -> Result<(Response<'static>, flow::Transition)> {
         match self.mailbox.fetch(sequence_set, attributes, uid).await {
-            Ok(resp) => Ok((
+            Ok((resp, enable_condstore)) => {
+                if enable_condstore {
+                    self.client_capabilities.enable_condstore();
+                }
+                Ok((
                     Response::build()
                         .to_req(self.req)
                         .message("FETCH completed")
                         .set_body(resp)
                         .ok()?,
                     flow::Transition::None,
-            )),
+                ))
+            },
             Err(e) => Ok((
                 Response::build()
                     .to_req(self.req)

src/imap/mailbox_view.rs

@@ -259,7 +259,7 @@ impl MailboxView {
         sequence_set: &SequenceSet,
         attributes: &'b MacroOrMessageDataItemNames<'static>,
         is_uid_fetch: &bool,
-    ) -> Result<Vec<Body<'static>>> {
+    ) -> Result<(Vec<Body<'static>>, bool)> {
         // [1/6] Pre-compute data
         //  a. what are the uuids of the emails we want?
         //  b. do we need to fetch the full body?
@@ -316,7 +316,7 @@ impl MailboxView {
             .collect::<Result<_, _>>()?;
 
         // [6/6] Build the final result that will be sent to the client.
-        Ok(imap_ret)
+        Ok((imap_ret, ap.is_enabling_condstore()))
     }
 
     /// A naive search implementation...