From 8443f342fd5368931696363c0d16fc11eb14f5d9 Mon Sep 17 00:00:00 2001
From: Joe Betz <jpbetz@google.com>
Date: Wed, 30 Sep 2020 18:55:21 -0700
Subject: [PATCH] Fix noop granular case for atomic<->granular schema changes

---
 typed/reconcile_schema.go      |  7 ++++---
 typed/reconcile_schema_test.go | 23 +++++++++++++++++++++++
 2 files changed, 27 insertions(+), 3 deletions(-)

diff --git a/typed/reconcile_schema.go b/typed/reconcile_schema.go
index fa67714c..5a8214ae 100644
--- a/typed/reconcile_schema.go
+++ b/typed/reconcile_schema.go
@@ -258,12 +258,13 @@ func buildGranularFieldSet(path fieldpath.Path, value *TypedValue) (*fieldpath.S
 	if err != nil {
 		return nil, errorf("toFieldSet: %v", err)
 	}
-	result := fieldpath.NewSet(path)
-	resultAtPath := descendToPath(result, path)
 	if valueFieldSetAtPath, ok := fieldSetAtPath(valueFieldSet, path); ok {
+		result := fieldpath.NewSet(path)
+		resultAtPath := descendToPath(result, path)
 		*resultAtPath = *valueFieldSetAtPath
+		return result, nil
 	}
-	return result, nil
+	return nil, nil
 }
 
 func fieldSetAtPath(node *fieldpath.Set, path fieldpath.Path) (*fieldpath.Set, bool) {
diff --git a/typed/reconcile_schema_test.go b/typed/reconcile_schema_test.go
index 29d30719..c4171412 100644
--- a/typed/reconcile_schema_test.go
+++ b/typed/reconcile_schema_test.go
@@ -267,6 +267,29 @@ var reconcileCases = []reconcileTestCase{{
 		_P("unchanged", "numeric"),
 	),
 	fixedFields: nil, // indicates no change
+}, {
+	name:         "no-change-empty-granular",
+	rootTypeName: "v1",
+	oldSchema:    granularSchema("v1"),
+	newSchema:    granularSchema("v1"),
+	liveObject: typed.YAMLObject(`
+struct: {}
+list: []
+objectList:
+  - keyA: a1
+    keyB: b1
+stringMap: {}
+unchanged: {}
+`),
+	oldFields: _NS(
+		_P("struct"),
+		_P("list"),
+		_P("objectList"),
+		_P("objectList", _KBF("keyA", "a1", "keyB", "b1")),
+		_P("objectList", _KBF("keyA", "a1", "keyB", "b1"), "value"),
+		_P("unchanged"),
+	),
+	fixedFields: nil, // indicates no change
 }}
 
 func TestReconcileFieldSetWithSchema(t *testing.T) {