fix recursive procedures

Author: James Cor

enginetest/queries/procedure_queries.go

@@ -2192,6 +2192,52 @@ END;`,
 			},
 		},
 	},
+	{
+		Name: "recursive procedure",
+		SetUpScript: []string{
+			`
+create procedure recursive_proc(in counter int)
+begin
+  set counter := counter + 1;
+  if counter > 3 then
+    select concat('ended with value: ', counter) as result;
+  else
+    call recursive_proc(counter);
+  end if;
+end;`,
+		},
+		Assertions: []ScriptTestAssertion{
+			{
+				Query: "call recursive_proc(1);",
+				Expected: []sql.Row{
+					{"ended with value: 4"},
+				},
+			},
+		},
+	},
+	{
+		Name: "multi recursive procedures",
+		SetUpScript: []string{
+			`
+create procedure recursive_proc(in counter int)
+begin
+  set counter := counter + 1;
+  if counter > 3 then
+    select concat('ended with value: ', counter) as result;
+  else
+    call recursive_proc(counter);
+  end if;
+end;`,
+		},
+		Assertions: []ScriptTestAssertion{
+			{
+				Query: "call recursive_proc(1);",
+				Expected: []sql.Row{
+					{"ended with value: 4"},
+				},
+			},
+		},
+	},
 }
 
 var ProcedureCallTests = []ScriptTest{

sql/core.go

@@ -894,7 +894,7 @@ type StoredProcParam struct {
 func (s *StoredProcParam) SetValue(val any) {
 	s.Value = val
 	s.HasBeenSet = true
-	if s.Reference != nil {
+	if s.Reference != nil && s != s.Reference {
 		s.Reference.SetValue(val)
 	}
 }

sql/rowexec/proc.go

@@ -223,6 +223,9 @@ func (b *BaseBuilder) buildCall(ctx *sql.Context, n *plan.Call, row sql.Row) (sq
 		paramName := strings.ToLower(param.Name)
 		for spp := ctx.Session.GetStoredProcParam(paramName); spp != nil; {
 			spp.Value = paramVal
+			if spp.Reference == spp {
+				break
+			}
 			spp = spp.Reference
 		}
 	}