Fix custom recursive loading in post_load callback

Before we called the callback while holding the statements locked. As a
result, if the callback tried to load another object of this type, it
failed. Now we unlock the statements (since we have completely loaded
the object from ODB's point of view) and then call the callback. The
callback test has been updated to test this situation.

1 files changed, 16 insertions, 0 deletions

diff --git a/odb/mysql/object-statements.ixx b/odb/mysql/object-statements.ixx
index 9dc772b..713a09f 100644
--- a/odb/mysql/object-statements.ixx
+++ b/odb/mysql/object-statements.ixx
@@ -8,6 +8,22 @@ namespace odb
   namespace mysql
   {
     //
+    // auto_unlock
+    //
+    inline object_statements_base::auto_unlock::
+    auto_unlock (object_statements_base& s)
+        : s_ (s)
+    {
+      s_.unlock ();
+    }
+
+    inline object_statements_base::auto_unlock::
+    ~auto_unlock ()
+    {
+      s_.lock ();
+    }
+
+    //
     // auto_lock
     //
     template <typename T>