add option to choose prepend/append in merge

api/filters/patchstrategicmerge/patchstrategicmerge.go

@@ -18,7 +18,12 @@ var _ kio.Filter = Filter{}
 func (pf Filter) Filter(nodes []*yaml.RNode) ([]*yaml.RNode, error) {
 	var result []*yaml.RNode
 	for i := range nodes {
-		r, err := merge2.Merge(pf.Patch, nodes[i])
+		r, err := merge2.Merge(
+			pf.Patch, nodes[i],
+			yaml.MergeOptions{
+				ListIncreaseDirection: yaml.MergeOptionsListPrepend,
+			},
+		)
 		if err != nil {
 			return nil, err
 		}

api/filters/patchstrategicmerge/patchstrategicmerge_test.go

@@ -67,10 +67,10 @@ spec:
   template:
     spec:
       containers:
+      - name: foo0
       - name: foo1
       - name: foo2
       - name: foo3
-      - name: foo0
 `,
 		},
 		"volumes patch": {
@@ -107,10 +107,10 @@ spec:
   template:
     spec:
       volumes:
+      - name: foo0
       - name: foo1
       - name: foo2
       - name: foo3
-      - name: foo0
 `,
 		},
 		"nested patch": {

api/krusty/baseandoverlaymedium_test.go

@@ -225,13 +225,13 @@ spec:
     spec:
       containers:
       - env:
-        - name: foo
-          value: bar
         - name: FOO
           valueFrom:
             configMapKeyRef:
               key: somekey
               name: test-infra-app-env-8h5mh7f7ch
+        - name: foo
+          value: bar
         image: nginx:1.8.0
         name: nginx
         ports:

api/krusty/generatormergeandreplace_test.go

@@ -385,12 +385,12 @@ spec:
       - gcePersistentDisk:
           pdName: nginx-persistent-storage
         name: nginx-persistent-storage
-      - configMap:
-          name: staging-team-foo-configmap-in-base-hc6g9dk6g9
-        name: configmap-in-base
       - configMap:
           name: staging-configmap-in-overlay-dc6fm46dhm
         name: configmap-in-overlay
+      - configMap:
+          name: staging-team-foo-configmap-in-base-hc6g9dk6g9
+        name: configmap-in-base
 ---
 apiVersion: v1
 kind: Service

api/krusty/multiplepatch_test.go

@@ -146,12 +146,12 @@ spec:
       - gcePersistentDisk:
           pdName: nginx-persistent-storage
         name: nginx-persistent-storage
-      - configMap:
-          name: a-b-configmap-in-base-798k5k7g9f
-        name: configmap-in-base
       - configMap:
           name: a-configmap-in-overlay-dc6fm46dhm
         name: configmap-in-overlay
+      - configMap:
+          name: a-b-configmap-in-base-798k5k7g9f
+        name: configmap-in-base
 ---
 apiVersion: v1
 kind: Service
@@ -351,12 +351,12 @@ spec:
       - gcePersistentDisk:
           pdName: nginx-persistent-storage
         name: nginx-persistent-storage
-      - configMap:
-          name: staging-team-foo-configmap-in-base-798k5k7g9f
-        name: configmap-in-base
       - configMap:
           name: staging-configmap-in-overlay-dc6fm46dhm
         name: configmap-in-overlay
+      - configMap:
+          name: staging-team-foo-configmap-in-base-798k5k7g9f
+        name: configmap-in-base
 ---
 apiVersion: v1
 kind: Service