From 004c80c25c0ced9f08fd7dacce4c069434e68be6 Mon Sep 17 00:00:00 2001
From: renshaohai83 <renshaohai@sohu.com>
Date: Wed, 18 Oct 2017 16:48:42 +0800
Subject: [PATCH] To support if DDL is upgraded first and application could be
 upgraded smoothly

To support if DDL is upgraded first and application could be upgraded
smoothly
---
 queries/reflect.go      | 8 ++++++--
 queries/reflect_test.go | 6 ++++--
 2 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/queries/reflect.go b/queries/reflect.go
index 9c55b336e..1e04a6d68 100644
--- a/queries/reflect.go
+++ b/queries/reflect.go
@@ -279,8 +279,8 @@ ColLoop:
 				continue ColLoop
 			}
 		}
-
-		return nil, errors.Errorf("could not find struct field name in mapping: %s", name)
+		// if c doesn't exist in the model, the pointer will be the zero value in the ptrs array and it's value will be thrown away
+		continue
 	}
 
 	return ptrs, nil
@@ -309,6 +309,10 @@ func ValuesFromMapping(val reflect.Value, mapping []uint64) []interface{} {
 // ptrFromMapping expects to be passed an addressable struct that it's looking
 // for things on.
 func ptrFromMapping(val reflect.Value, mapping uint64, addressOf bool) reflect.Value {
+	if mapping == 0 {
+		var ignored interface{}
+		return reflect.ValueOf(&ignored)
+	}
 	for i := 0; i < 8; i++ {
 		v := (mapping >> uint(i*8)) & sentinel
 
diff --git a/queries/reflect_test.go b/queries/reflect_test.go
index 8d83ed35b..bad403d36 100644
--- a/queries/reflect_test.go
+++ b/queries/reflect_test.go
@@ -283,8 +283,7 @@ func TestValuesFromMapping(t *testing.T) {
 			IntP: new(int),
 		},
 	}
-
-	mapping := []uint64{testMakeMapping(0), testMakeMapping(1), testMakeMapping(2, 0), testMakeMapping(2, 1)}
+	mapping := []uint64{testMakeMapping(0), testMakeMapping(1), testMakeMapping(2, 0), testMakeMapping(2, 1), 0}
 	v := ValuesFromMapping(reflect.Indirect(reflect.ValueOf(val)), mapping)
 
 	if got := v[0].(int); got != 5 {
@@ -299,6 +298,9 @@ func TestValuesFromMapping(t *testing.T) {
 	if got := v[3].(int); got != 0 {
 		t.Error("nested pointer was wrong:", got)
 	}
+	if got := *v[4].(*interface{}); got != nil {
+		t.Error("nil pointer was not be ignored:", got)
+	}
 }
 
 func TestPtrsFromMapping(t *testing.T) {