Detect situations where session is required but not used

Throw session_required.

2 files changed, 13 insertions, 0 deletions

diff --git a/odb/exceptions.cxx b/odb/exceptions.cxx
index 9089a5b..b200843 100644
--- a/odb/exceptions.cxx
+++ b/odb/exceptions.cxx
@@ -46,6 +46,12 @@ namespace odb
     return "session not in effect in this thread";
   }
 
+  const char* session_required::
+  what () const throw ()
+  {
+    return "session required to load this object relationship";
+  }
+
   const char* deadlock::
   what () const throw ()
   {
diff --git a/odb/exceptions.hxx b/odb/exceptions.hxx
index 682766a..b55b2a4 100644
--- a/odb/exceptions.hxx
+++ b/odb/exceptions.hxx
@@ -55,6 +55,12 @@ namespace odb
     what () const throw ();
   };
 
+  struct LIBODB_EXPORT session_required: exception
+  {
+    virtual const char*
+    what () const throw ();
+  };
+
   // Database operations exceptions.
   //
   struct LIBODB_EXPORT recoverable: exception
@@ -138,6 +144,7 @@ namespace odb
 
     using odb::already_in_session;
     using odb::not_in_session;
+    using odb::session_required;
 
     using odb::recoverable;
     using odb::deadlock;