Handle user variables (@-vars) as OUT and INOUT parameters in SPs.

mysql-test/r/sp.result:
  Test cases for user variables (@-vars) as OUT and INOUT parameters.
mysql-test/t/sp.test:
  Test cases for user variables (@-vars) as OUT and INOUT parameters.
sql/item_func.h:
  We need to be able to detect Item_func_get_user_vars when used as arguments to SPs.
sql/sp_head.cc:
  Handle user variables (@-vars) as OUT and INOUT parameters.
  But we still just ignore it, if it's anything else.

mysql-test/r/sp.result

@@ -93,8 +93,12 @@ id	data
 zip	100
 delete from t1;
 drop procedure zip;
-drop procedure zap;
 drop procedure bar;
+call zap(7, @zap);
+select @zap;
+@zap
+8
+drop procedure zap;
 create procedure c1(x int)
 call c2("c", x);
 create procedure c2(s char(16), x int)
@@ -132,7 +136,17 @@ io1	1
 delete from t1;
 drop procedure iotest;
 drop procedure inc2;
+create procedure incr(inout x int)
+call inc(x);
+select @zap;
+@zap
+8
+call incr(@zap);
+select @zap;
+@zap
+9
 drop procedure inc;
+drop procedure incr;
 create procedure cbv1()
 begin
 declare y int default 3;

mysql-test/t/sp.test

@@ -122,9 +122,14 @@ call zip("zip", 99)|
 select * from t1|
 delete from t1|
 drop procedure zip|
-drop procedure zap|
 drop procedure bar|
 
+# Top-level OUT parameter
+call zap(7, @zap)|
+select @zap|
+
+drop procedure zap|
+
 
 # "Deep" calls...
 create procedure c1(x int)
@@ -165,8 +170,19 @@ select * from t1|
 delete from t1|
 drop procedure iotest|
 drop procedure inc2|
-drop procedure inc|
 
+# Propagating top-level @-vars
+create procedure incr(inout x int)
+  call inc(x)|
+
+# Before
+select @zap|
+call incr(@zap)|
+# After
+select @zap|
+
+drop procedure inc|
+drop procedure incr|
 
 # Call-by-value test
 #  The expected result is:

sql/item_func.h

@@ -46,7 +46,8 @@ class Item_func :public Item_result_field
 		  SP_TOUCHES_FUNC,SP_CROSSES_FUNC,SP_WITHIN_FUNC,
 		  SP_CONTAINS_FUNC,SP_OVERLAPS_FUNC,
 		  SP_STARTPOINT,SP_ENDPOINT,SP_EXTERIORRING,
-		  SP_POINTN,SP_GEOMETRYN,SP_INTERIORRINGN};
+		  SP_POINTN,SP_GEOMETRYN,SP_INTERIORRINGN,
+                  GUSERVAR_FUNC};
   enum optimize_type { OPTIMIZE_NONE,OPTIMIZE_KEY,OPTIMIZE_OP, OPTIMIZE_NULL };
   enum Type type() const { return FUNC_ITEM; }
   virtual enum Functype functype() const   { return UNKNOWN_FUNC; }
@@ -926,6 +927,8 @@ class Item_func_get_user_var :public Item_func
   Item_func_get_user_var(LEX_STRING a):
     Item_func(), name(a) {}
   user_var_entry *get_entry();
+  enum Functype functype() const { return GUSERVAR_FUNC; }
+  LEX_STRING get_name() { return name; }
   double val();
   longlong val_int();
   String *val_str(String* str);

sql/sp_head.cc

@@ -389,7 +389,8 @@ sp_head::execute_procedure(THD *thd, List<Item> *args)
 	else
 	  nctx->push_item(sp_eval_func_item(thd, it,pvar->type)); // IN or INOUT
 	// Note: If it's OUT or INOUT, it must be a variable.
-	// QQ: Need to handle "global" user/host variables too!!!
+	// QQ: We can check for global variables here, or should we do it
+	//     while parsing?
 	if (pvar->mode == sp_param_in)
 	  nctx->set_oindex(i, -1); // IN
 	else			// OUT or INOUT
@@ -427,22 +428,27 @@ sp_head::execute_procedure(THD *thd, List<Item> *args)
 	if (! tmp_octx)
 	  octx->set_item(nctx->get_oindex(i), nctx->get_item(i));
 	else
+	{
+	  // QQ Currently we just silently ignore non-user-variable arguments.
+	  //    We should check this during parsing, when setting up the call
+	  //    above
+	  if (it->type() == Item::FUNC_ITEM)
+	  {
+	    Item_func *fi= static_cast<Item_func*>(it);
+
+	    if (fi->functype() == Item_func::GUSERVAR_FUNC)
 	    {			// A global user variable
-#if NOT_USED_NOW
-	  // QQ This works if the parameter really is a user variable, but
-	  // for the moment we can't assure that, so it will crash if it's
-	  // something else. So for now, we just do nothing, to avoid a crash.
-	  // Note: This also assumes we have a get_name() method in
-	  //       the Item_func_get_user_var class.
 	      Item *item= nctx->get_item(i);
 	      Item_func_set_user_var *suv;
-	  Item_func_get_user_var *guv= static_cast<Item_func_get_user_var*>(it);
+	      Item_func_get_user_var *guv=
+		static_cast<Item_func_get_user_var*>(fi);
 
 	      suv= new Item_func_set_user_var(guv->get_name(), item);
 	      suv->fix_fields(thd, NULL, &item);
 	      suv->fix_length_and_dec();
 	      suv->update();
-#endif
+	    }
+	  }
 	}
       }
     }