sort: show warning when sort is not supported

Use the capabilities returned by the backend to check whether sort is
implemented when the user tries to use the sort command. Print a warning
to the log when a sort request is silently dropped by the backend.

Suggested-by: |cos|
Signed-off-by: Koni Marti <koni.marti@gmail.com>
Acked-by: Robin Jarry <robin@jarry.cc>

3 files changed, 13 insertions, 0 deletions

diff --git a/commands/account/sort.go b/commands/account/sort.go
index e9ee4a3..f8cb94c 100644
--- a/commands/account/sort.go
+++ b/commands/account/sort.go
@@ -72,6 +72,12 @@ func (Sort) Execute(aerc *widgets.Aerc, args []string) error {
 		return errors.New("Messages still loading.")
 	}
 
+	if c := store.Capabilities(); c != nil {
+		if !c.Sort {
+			return errors.New("Sorting is not available for this backend.")
+		}
+	}
+
 	var err error
 	var sortCriteria []*types.SortCriterion
 	if len(args[1:]) == 0 {
diff --git a/lib/msgstore.go b/lib/msgstore.go
index 783ce5d..c9f8fd9 100644
--- a/lib/msgstore.go
+++ b/lib/msgstore.go
@@ -847,3 +847,8 @@ func (store *MessageStore) FindIndexByUid(uid uint32) int {
 	}
 	return -1
 }
+
+// Capabilities returns a models.Capabilities struct or nil if not available
+func (store *MessageStore) Capabilities() *models.Capabilities {
+	return store.DirInfo.Caps
+}
diff --git a/worker/imap/open.go b/worker/imap/open.go
index 636b936..2d76f43 100644
--- a/worker/imap/open.go
+++ b/worker/imap/open.go
@@ -53,6 +53,8 @@ func (imapw *IMAPWorker) handleFetchDirectoryContents(
 		if err != nil {
 			// Non fatal, but we do want to print to get some debug info
 			logging.Errorf("can't check for SORT support: %v", err)
+		} else if len(sortCriteria) > 0 {
+			logging.Warnf("SORT is not supported but requested: list messages by UID")
 		}
 		uids, err = imapw.client.UidSearch(searchCriteria)
 	}