#
#
# patch "work.cc"
#  from [dd642c4fb0d409f31421f8f0945656994cd9f619]
#    to [f7b4308b3debf6578e90b4bee052decef5971bff]
# 
# patch "work.hh"
#  from [884c5981949c924b1f40d950809d862f4f6de2f4]
#    to [b2a0f077a4ad9482283a6dab697778ff0815dc1e]
#
============================================================
--- work.cc	dd642c4fb0d409f31421f8f0945656994cd9f619
+++ work.cc	f7b4308b3debf6578e90b4bee052decef5971bff
@@ -292,10 +292,25 @@ void
 }
 
 void
+workspace::require_parents_in_db(database & db,
+                                 revision_t const & rev)
+{
+  for (edge_map::const_iterator i = rev.edges.begin();
+       i != rev.edges.end(); i++)
+    {
+      revision_id const & parent(edge_old_revision(i));
+      E(db.revision_exists(parent), origin::user,
+        F("parent revision %s does not exist, did you specify the wrong database?")
+        % parent);
+    }
+}
+
+void
 workspace::get_parent_rosters(database & db, parent_map & parents)
 {
   revision_t rev;
   get_work_rev(rev);
+  require_parents_in_db(db, rev);
 
   parents.clear();
   for (edge_map::const_iterator i = rev.edges.begin();
@@ -314,6 +329,7 @@ workspace::get_current_roster_shape(data
 {
   revision_t rev;
   get_work_rev(rev);
+  require_parents_in_db(db, rev);
   revision_id new_rid(fake_id());
 
   // If there is just one parent, it might be the null ID, which
============================================================
--- work.hh	884c5981949c924b1f40d950809d862f4f6de2f4
+++ work.hh	b2a0f077a4ad9482283a6dab697778ff0815dc1e
@@ -102,6 +102,9 @@ private:
   // This is used by a lot of instance methods.
   lua_hooks & lua;
 
+  // Give a nice error if the parent revisions aren't in the db
+  void require_parents_in_db(database & db, revision_t const & rev);
+
   // Interfaces.
 public:
   static void require_workspace();