Send a item-not-found error when the “after” value is not in the archive

src/database/database.hpp

@@ -22,6 +22,7 @@ class Database
 {
  public:
   using time_point = std::chrono::system_clock::time_point;
+  struct RecordNotFound: public std::exception {};
 
   struct Uuid: Column<std::string> { static constexpr auto name = "uuid_"; };
 

src/xmpp/biboumi_component.cpp

@@ -467,8 +467,12 @@ void BiboumiComponent::handle_iq(const Stanza& stanza)
 #ifdef USE_DATABASE
       else if ((query = stanza.get_child("query", MAM_NS)))
         {
-          if (this->handle_mam_request(stanza))
-            stanza_error.disable();
+          try {
+              if (this->handle_mam_request(stanza))
+                stanza_error.disable();
+            } catch (const Database::RecordNotFound& exc) {
+              error_name = "item-not-found";
+            }
         }
       else if ((query = stanza.get_child("query", MUC_OWNER_NS)))
         {