support merge strategy in list

kyaml/yaml/merge2/list_test.go

@@ -142,6 +142,109 @@ spec:
       - name: foo3
 `,
 	},
+	{description: `merge k8s deployment containers -- $patch directive`,
+		source: `
+    apiVersion: apps/v1
+    kind: Deployment
+    spec:
+      template:
+        spec:
+          containers:
+          - name: foo1
+          - name: foo2
+          - name: foo3
+          - $patch: merge
+`,
+		dest: `
+    apiVersion: apps/v1
+    kind: Deployment
+    spec:
+      template:
+        spec:
+          containers:
+          - name: foo4
+          - name: foo5
+`,
+		expected: `
+    apiVersion: apps/v1
+    kind: Deployment
+    spec:
+      template:
+        spec:
+          containers:
+          - name: foo1
+          - name: foo2
+          - name: foo3
+          - name: foo4
+          - name: foo5
+`,
+	},
+	{description: `replace k8s deployment containers -- $patch directive`,
+		source: `
+    apiVersion: apps/v1
+    kind: Deployment
+    spec:
+      template:
+        spec:
+          containers:
+          - name: foo1
+          - name: foo2
+          - name: foo3
+          - $patch: replace
+`,
+		dest: `
+    apiVersion: apps/v1
+    kind: Deployment
+    spec:
+      template:
+        spec:
+          containers:
+          - name: foo4
+          - name: foo5
+`,
+		expected: `
+    apiVersion: apps/v1
+    kind: Deployment
+    spec:
+      template:
+        spec:
+          containers:
+          - name: foo1
+          - name: foo2
+          - name: foo3
+`,
+	},
+	{description: `remove k8s deployment containers -- $patch directive`,
+		source: `
+    apiVersion: apps/v1
+    kind: Deployment
+    spec:
+      template:
+        spec:
+          containers:
+          - name: foo1
+          - name: foo2
+          - name: foo3
+          - $patch: delete
+`,
+		dest: `
+    apiVersion: apps/v1
+    kind: Deployment
+    spec:
+      template:
+        spec:
+          containers:
+          - name: foo4
+          - name: foo5
+`,
+		expected: `
+    apiVersion: apps/v1
+    kind: Deployment
+    spec:
+      template:
+        spec: {}
+`,
+	},
 
 	{description: `replace List -- different value in dest`,
 		source: `

kyaml/yaml/merge2/merge2.go

@@ -61,7 +61,7 @@ func (m Merger) VisitMap(nodes walk.Sources, s *openapi.ResourceSchema) (*yaml.R
 		return walk.ClearNode, nil
 	}
 
-	ps, err := determineMappingNodePatchStrategy(nodes.Origin())
+	ps, err := determineSmpDirective(nodes.Origin())
 	if err != nil {
 		return nil, err
 	}
@@ -115,8 +115,20 @@ func (m Merger) VisitList(nodes walk.Sources, s *openapi.ResourceSchema, kind wa
 	if nodes.Origin().IsTaggedNull() {
 		return walk.ClearNode, nil
 	}
-	// Recursively Merge dest
-	return nodes.Dest(), nil
+
+	ps, err := determineSmpDirective(nodes.Origin())
+	if err != nil {
+		return nil, err
+	}
+
+	switch ps {
+	case smpDelete:
+		return walk.ClearNode, nil
+	case smpReplace:
+		return nodes.Origin(), nil
+	default:
+		return nodes.Dest(), nil
+	}
 }
 
 func (m Merger) SetStyle(sources walk.Sources) error {

kyaml/yaml/merge2/smpdirective.go

@@ -42,9 +42,31 @@ func determineSmpDirective(patch *yaml.RNode) (smpDirective, error) {
 	}
 }
 
-// TODO: what should this do?
-func determineSequenceNodePatchStrategy(_ *yaml.RNode) (smpDirective, error) {
-	return smpMerge, nil
+func determineSequenceNodePatchStrategy(patch *yaml.RNode) (smpDirective, error) {
+	// get the $patch element
+	node, err := patch.Pipe(yaml.GetElementByKey(strategicMergePatchDirectiveKey))
+	// if there are more than 1 key/value pair in the map, then this $patch
+	// is not for the sequence
+	if err != nil || node == nil || node.YNode() == nil || len(node.Content()) > 2 {
+		return smpMerge, nil
+	}
+	// get the value
+	value, err := node.Pipe(yaml.Get(strategicMergePatchDirectiveKey))
+	if err != nil || value == nil || value.YNode() == nil {
+		return smpMerge, nil
+	}
+	v := value.YNode().Value
+	if v == smpDelete.String() {
+		return smpDelete, elideSequencePatchDirective(patch, v)
+	}
+	if v == smpReplace.String() {
+		return smpReplace, elideSequencePatchDirective(patch, v)
+	}
+	if v == smpMerge.String() {
+		return smpMerge, elideSequencePatchDirective(patch, v)
+	}
+	return smpUnknown, fmt.Errorf(
+		"unknown patch strategy '%s'", v)
 }
 
 func determineMappingNodePatchStrategy(patch *yaml.RNode) (smpDirective, error) {
@@ -54,18 +76,26 @@ func determineMappingNodePatchStrategy(patch *yaml.RNode) (smpDirective, error)
 	}
 	v := node.YNode().Value
 	if v == smpDelete.String() {
-		return smpDelete, elidePatchDirective(patch)
+		return smpDelete, elideMappingPatchDirective(patch)
 	}
 	if v == smpReplace.String() {
-		return smpReplace, elidePatchDirective(patch)
+		return smpReplace, elideMappingPatchDirective(patch)
 	}
 	if v == smpMerge.String() {
-		return smpMerge, elidePatchDirective(patch)
+		return smpMerge, elideMappingPatchDirective(patch)
 	}
 	return smpUnknown, fmt.Errorf(
 		"unknown patch strategy '%s'", v)
 }
 
-func elidePatchDirective(patch *yaml.RNode) error {
+func elideMappingPatchDirective(patch *yaml.RNode) error {
 	return patch.PipeE(yaml.Clear(strategicMergePatchDirectiveKey))
 }
+
+func elideSequencePatchDirective(patch *yaml.RNode, value string) error {
+	return patch.PipeE(yaml.ElementSetter{
+		Element: nil,
+		Key:     strategicMergePatchDirectiveKey,
+		Value:   value,
+	})
+}

kyaml/yaml/merge2/smpdirective_test.go

@@ -26,6 +26,45 @@ func Test_determineSmpDirective(t *testing.T) {
 - one
 - two
 - three
+- $patch: merge
+`,
+			expected: smpMerge,
+			elided: `- one
+- two
+- three
+`,
+		},
+		"list replace": {
+			patch: `
+- one
+- two
+- three
+- $patch: replace
+`,
+			expected: smpReplace,
+			elided: `- one
+- two
+- three
+`,
+		},
+		"list delete": {
+			patch: `
+- one
+- two
+- three
+- $patch: delete
+`,
+			expected: smpDelete,
+			elided: `- one
+- two
+- three
+`,
+		},
+		"list default": {
+			patch: `
+- one
+- two
+- three
 `,
 			expected: smpMerge,
 			elided: `- one