From db9807134f5fc0d25017319da484506d195286ae Mon Sep 17 00:00:00 2001
From: Wen Bo Li <50884368+wenovus@users.noreply.github.com>
Date: Tue, 24 Nov 2020 17:53:44 -0500
Subject: [PATCH] Ignore default data values in findSetLeaves (#476)

* Ignore default data values in findSetLeaves
---
 ygot/diff.go        |  3 ++-
 ygot/diff_test.go   | 11 +++++++++++
 ygot/render_test.go |  5 +++--
 3 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/ygot/diff.go b/ygot/diff.go
index 9ec324e7a..06b77441b 100644
--- a/ygot/diff.go
+++ b/ygot/diff.go
@@ -263,7 +263,8 @@ func findSetLeaves(s GoStruct, opts ...DiffOpt) (map[*pathSpec]interface{}, erro
 
 		ni.Annotation = []interface{}{vp}
 
-		if util.IsNilOrInvalidValue(ni.FieldValue) || util.IsValueStructPtr(ni.FieldValue) || util.IsValueMap(ni.FieldValue) {
+		// Ignore non-data, or default data values.
+		if util.IsNilOrInvalidValue(ni.FieldValue) || util.IsValueNilOrDefault(ni.FieldValue.Interface()) || util.IsValueStructPtr(ni.FieldValue) || util.IsValueMap(ni.FieldValue) {
 			return
 		}
 
diff --git a/ygot/diff_test.go b/ygot/diff_test.go
index 328a9b606..a640eb807 100644
--- a/ygot/diff_test.go
+++ b/ygot/diff_test.go
@@ -151,6 +151,7 @@ type basicStruct struct {
 	StringValue *string                     `path:"string-value"`
 	StructValue *basicStructTwo             `path:"struct-value"`
 	MapValue    map[string]*basicListMember `path:"map-list"`
+	EmptyValue  YANGEmpty                   `path:"empty-value"`
 }
 
 func (*basicStruct) IsYANGGoStruct() {}
@@ -429,6 +430,16 @@ func TestFindSetLeaves(t *testing.T) {
 		desc:     "struct with fields missing path annotation",
 		inStruct: &errorStruct{Value: String("foo")},
 		wantErr:  "error from ForEachDataField iteration: field Value did not specify a path",
+	}, {
+		desc:     "struct with empty value",
+		inStruct: &basicStruct{EmptyValue: YANGEmpty(true)},
+		want: map[*pathSpec]interface{}{
+			{
+				gNMIPaths: []*gnmipb.Path{{
+					Elem: []*gnmipb.PathElem{{Name: "empty-value"}},
+				}},
+			}: YANGEmpty(true),
+		},
 	}, {
 		desc: "multi-level string values",
 		inStruct: &basicStruct{
diff --git a/ygot/render_test.go b/ygot/render_test.go
index 3e06ad7ff..53a3e1928 100644
--- a/ygot/render_test.go
+++ b/ygot/render_test.go
@@ -838,8 +838,9 @@ func (*renderExampleUnionEnum) IsRenderUnionExample() {}
 
 // renderExampleChild is a child of the renderExample struct.
 type renderExampleChild struct {
-	Val  *uint64  `path:"val"`
-	Enum EnumTest `path:"enum"`
+	Val   *uint64   `path:"val"`
+	Enum  EnumTest  `path:"enum"`
+	Empty YANGEmpty `path:"empty"`
 }
 
 // IsYANGGoStruct implements the GoStruct interface.