vendor files

vendor/k8s.io/apimachinery/pkg/util/strategicpatch/BUILD

@@ -0,0 +1,61 @@
+package(default_visibility = ["//visibility:public"])
+
+load(
+    "@io_bazel_rules_go//go:def.bzl",
+    "go_library",
+    "go_test",
+)
+
+go_test(
+    name = "go_default_test",
+    srcs = ["patch_test.go"],
+    data = [
+        "testdata/swagger-merge-item.json",
+        "testdata/swagger-precision-item.json",
+    ],
+    importpath = "k8s.io/apimachinery/pkg/util/strategicpatch",
+    library = ":go_default_library",
+    deps = [
+        "//vendor/github.com/davecgh/go-spew/spew:go_default_library",
+        "//vendor/github.com/ghodss/yaml:go_default_library",
+        "//vendor/k8s.io/apimachinery/pkg/runtime:go_default_library",
+        "//vendor/k8s.io/apimachinery/pkg/util/json:go_default_library",
+        "//vendor/k8s.io/apimachinery/pkg/util/mergepatch:go_default_library",
+        "//vendor/k8s.io/apimachinery/pkg/util/sets:go_default_library",
+        "//vendor/k8s.io/apimachinery/pkg/util/strategicpatch/testing:go_default_library",
+    ],
+)
+
+go_library(
+    name = "go_default_library",
+    srcs = [
+        "errors.go",
+        "meta.go",
+        "patch.go",
+        "types.go",
+    ],
+    importpath = "k8s.io/apimachinery/pkg/util/strategicpatch",
+    deps = [
+        "//vendor/k8s.io/apimachinery/pkg/apis/meta/v1/unstructured:go_default_library",
+        "//vendor/k8s.io/apimachinery/pkg/util/json:go_default_library",
+        "//vendor/k8s.io/apimachinery/pkg/util/mergepatch:go_default_library",
+        "//vendor/k8s.io/apimachinery/third_party/forked/golang/json:go_default_library",
+        "//vendor/k8s.io/kube-openapi/pkg/util/proto:go_default_library",
+    ],
+)
+
+filegroup(
+    name = "package-srcs",
+    srcs = glob(["**"]),
+    tags = ["automanaged"],
+    visibility = ["//visibility:private"],
+)
+
+filegroup(
+    name = "all-srcs",
+    srcs = [
+        ":package-srcs",
+        "//staging/src/k8s.io/apimachinery/pkg/util/strategicpatch/testing:all-srcs",
+    ],
+    tags = ["automanaged"],
+)

vendor/k8s.io/apimachinery/pkg/util/strategicpatch/OWNERS

@@ -0,0 +1,5 @@
+approvers:
+- pwittrock
+reviewers:
+- mengqiy
+- apelisse

vendor/k8s.io/apimachinery/pkg/util/strategicpatch/errors.go

@@ -0,0 +1,49 @@
+/*
+Copyright 2017 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package strategicpatch
+
+import (
+	"fmt"
+)
+
+type LookupPatchMetaError struct {
+	Path string
+	Err  error
+}
+
+func (e LookupPatchMetaError) Error() string {
+	return fmt.Sprintf("LookupPatchMetaError(%s): %v", e.Path, e.Err)
+}
+
+type FieldNotFoundError struct {
+	Path  string
+	Field string
+}
+
+func (e FieldNotFoundError) Error() string {
+	return fmt.Sprintf("unable to find api field %q in %s", e.Field, e.Path)
+}
+
+type InvalidTypeError struct {
+	Path     string
+	Expected string
+	Actual   string
+}
+
+func (e InvalidTypeError) Error() string {
+	return fmt.Sprintf("invalid type for %s: got %q, expected %q", e.Path, e.Actual, e.Expected)
+}

vendor/k8s.io/apimachinery/pkg/util/strategicpatch/meta.go

@@ -0,0 +1,194 @@
+/*
+Copyright 2017 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package strategicpatch
+
+import (
+	"errors"
+	"fmt"
+	"reflect"
+
+	"k8s.io/apimachinery/pkg/util/mergepatch"
+	forkedjson "k8s.io/apimachinery/third_party/forked/golang/json"
+	openapi "k8s.io/kube-openapi/pkg/util/proto"
+)
+
+type PatchMeta struct {
+	patchStrategies []string
+	patchMergeKey   string
+}
+
+func (pm PatchMeta) GetPatchStrategies() []string {
+	if pm.patchStrategies == nil {
+		return []string{}
+	}
+	return pm.patchStrategies
+}
+
+func (pm PatchMeta) SetPatchStrategies(ps []string) {
+	pm.patchStrategies = ps
+}
+
+func (pm PatchMeta) GetPatchMergeKey() string {
+	return pm.patchMergeKey
+}
+
+func (pm PatchMeta) SetPatchMergeKey(pmk string) {
+	pm.patchMergeKey = pmk
+}
+
+type LookupPatchMeta interface {
+	// LookupPatchMetadataForStruct gets subschema and the patch metadata (e.g. patch strategy and merge key) for map.
+	LookupPatchMetadataForStruct(key string) (LookupPatchMeta, PatchMeta, error)
+	// LookupPatchMetadataForSlice get subschema and the patch metadata for slice.
+	LookupPatchMetadataForSlice(key string) (LookupPatchMeta, PatchMeta, error)
+	// Get the type name of the field
+	Name() string
+}
+
+type PatchMetaFromStruct struct {
+	T reflect.Type
+}
+
+func NewPatchMetaFromStruct(dataStruct interface{}) (PatchMetaFromStruct, error) {
+	t, err := getTagStructType(dataStruct)
+	return PatchMetaFromStruct{T: t}, err
+}
+
+var _ LookupPatchMeta = PatchMetaFromStruct{}
+
+func (s PatchMetaFromStruct) LookupPatchMetadataForStruct(key string) (LookupPatchMeta, PatchMeta, error) {
+	fieldType, fieldPatchStrategies, fieldPatchMergeKey, err := forkedjson.LookupPatchMetadataForStruct(s.T, key)
+	if err != nil {
+		return nil, PatchMeta{}, err
+	}
+
+	return PatchMetaFromStruct{T: fieldType},
+		PatchMeta{
+			patchStrategies: fieldPatchStrategies,
+			patchMergeKey:   fieldPatchMergeKey,
+		}, nil
+}
+
+func (s PatchMetaFromStruct) LookupPatchMetadataForSlice(key string) (LookupPatchMeta, PatchMeta, error) {
+	subschema, patchMeta, err := s.LookupPatchMetadataForStruct(key)
+	if err != nil {
+		return nil, PatchMeta{}, err
+	}
+	elemPatchMetaFromStruct := subschema.(PatchMetaFromStruct)
+	t := elemPatchMetaFromStruct.T
+
+	var elemType reflect.Type
+	switch t.Kind() {
+	// If t is an array or a slice, get the element type.
+	// If element is still an array or a slice, return an error.
+	// Otherwise, return element type.
+	case reflect.Array, reflect.Slice:
+		elemType = t.Elem()
+		if elemType.Kind() == reflect.Array || elemType.Kind() == reflect.Slice {
+			return nil, PatchMeta{}, errors.New("unexpected slice of slice")
+		}
+	// If t is an pointer, get the underlying element.
+	// If the underlying element is neither an array nor a slice, the pointer is pointing to a slice,
+	// e.g. https://github.com/kubernetes/kubernetes/blob/bc22e206c79282487ea0bf5696d5ccec7e839a76/staging/src/k8s.io/apimachinery/pkg/util/strategicpatch/patch_test.go#L2782-L2822
+	// If the underlying element is either an array or a slice, return its element type.
+	case reflect.Ptr:
+		t = t.Elem()
+		if t.Kind() == reflect.Array || t.Kind() == reflect.Slice {
+			t = t.Elem()
+		}
+		elemType = t
+	default:
+		return nil, PatchMeta{}, fmt.Errorf("expected slice or array type, but got: %s", s.T.Kind().String())
+	}
+
+	return PatchMetaFromStruct{T: elemType}, patchMeta, nil
+}
+
+func (s PatchMetaFromStruct) Name() string {
+	return s.T.Kind().String()
+}
+
+func getTagStructType(dataStruct interface{}) (reflect.Type, error) {
+	if dataStruct == nil {
+		return nil, mergepatch.ErrBadArgKind(struct{}{}, nil)
+	}
+
+	t := reflect.TypeOf(dataStruct)
+	// Get the underlying type for pointers
+	if t.Kind() == reflect.Ptr {
+		t = t.Elem()
+	}
+
+	if t.Kind() != reflect.Struct {
+		return nil, mergepatch.ErrBadArgKind(struct{}{}, dataStruct)
+	}
+
+	return t, nil
+}
+
+func GetTagStructTypeOrDie(dataStruct interface{}) reflect.Type {
+	t, err := getTagStructType(dataStruct)
+	if err != nil {
+		panic(err)
+	}
+	return t
+}
+
+type PatchMetaFromOpenAPI struct {
+	Schema openapi.Schema
+}
+
+func NewPatchMetaFromOpenAPI(s openapi.Schema) PatchMetaFromOpenAPI {
+	return PatchMetaFromOpenAPI{Schema: s}
+}
+
+var _ LookupPatchMeta = PatchMetaFromOpenAPI{}
+
+func (s PatchMetaFromOpenAPI) LookupPatchMetadataForStruct(key string) (LookupPatchMeta, PatchMeta, error) {
+	if s.Schema == nil {
+		return nil, PatchMeta{}, nil
+	}
+	kindItem := NewKindItem(key, s.Schema.GetPath())
+	s.Schema.Accept(kindItem)
+
+	err := kindItem.Error()
+	if err != nil {
+		return nil, PatchMeta{}, err
+	}
+	return PatchMetaFromOpenAPI{Schema: kindItem.subschema},
+		kindItem.patchmeta, nil
+}
+
+func (s PatchMetaFromOpenAPI) LookupPatchMetadataForSlice(key string) (LookupPatchMeta, PatchMeta, error) {
+	if s.Schema == nil {
+		return nil, PatchMeta{}, nil
+	}
+	sliceItem := NewSliceItem(key, s.Schema.GetPath())
+	s.Schema.Accept(sliceItem)
+
+	err := sliceItem.Error()
+	if err != nil {
+		return nil, PatchMeta{}, err
+	}
+	return PatchMetaFromOpenAPI{Schema: sliceItem.subschema},
+		sliceItem.patchmeta, nil
+}
+
+func (s PatchMetaFromOpenAPI) Name() string {
+	schema := s.Schema
+	return schema.GetName()
+}

vendor/k8s.io/apimachinery/pkg/util/strategicpatch/testdata/swagger-merge-item.json

@@ -0,0 +1,170 @@
+{
+  "swagger": "2.0",
+  "info": {
+    "title": "StrategicMergePatchTestingMergeItem",
+    "version": "v1.9.0"
+  },
+  "paths": {},
+  "definitions": {
+    "mergeItem": {
+      "description": "MergeItem is type definition for testing strategic merge.",
+      "required": [],
+      "properties": {
+        "name": {
+          "description": "Name field.",
+          "type": "string"
+        },
+        "value": {
+          "description": "Value field.",
+          "type": "string"
+        },
+        "other": {
+          "description": "Other field.",
+          "type": "string"
+        },
+        "mergingList": {
+          "description": "MergingList field.",
+          "type": "array",
+          "items": {
+            "$ref": "#/definitions/mergeItem"
+          },
+          "x-kubernetes-patch-merge-key": "name",
+          "x-kubernetes-patch-strategy": "merge"
+        },
+        "nonMergingList": {
+          "description": "NonMergingList field.",
+          "type": "array",
+          "items": {
+            "$ref": "#/definitions/mergeItem"
+          }
+        },
+        "mergingIntList": {
+          "description": "MergingIntList field.",
+          "type": "array",
+          "items": {
+            "type": "integer",
+            "format": "int32"
+          },
+          "x-kubernetes-patch-strategy": "merge"
+        },
+        "nonMergingIntList": {
+          "description": "NonMergingIntList field.",
+          "type": "array",
+          "items": {
+            "type": "integer",
+            "format": "int32"
+          }
+        },
+        "mergeItemPtr": {
+          "description": "MergeItemPtr field.",
+          "$ref": "#/definitions/mergeItem",
+          "x-kubernetes-patch-merge-key": "name",
+          "x-kubernetes-patch-strategy": "merge"
+        },
+        "simpleMap": {
+          "description": "SimpleMap field.",
+          "type": "object",
+          "additionalProperties": {
+            "type": "string"
+          }
+        },
+        "replacingItem": {
+          "description": "ReplacingItem field.",
+          "$ref": "#/definitions/io.k8s.apimachinery.pkg.runtime.RawExtension",
+          "x-kubernetes-patch-strategy": "replace"
+        },
+        "retainKeysMap": {
+          "description": "RetainKeysMap field.",
+          "$ref": "#/definitions/retainKeysMergeItem",
+          "x-kubernetes-patch-strategy": "retainKeys"
+        },
+        "retainKeysMergingList": {
+          "description": "RetainKeysMergingList field.",
+          "type": "array",
+          "items": {
+            "$ref": "#/definitions/mergeItem"
+          },
+          "x-kubernetes-patch-merge-key": "name",
+          "x-kubernetes-patch-strategy": "merge,retainKeys"
+        }
+      },
+      "x-kubernetes-group-version-kind": [
+        {
+          "group": "fake-group",
+          "kind": "mergeItem",
+          "version": "some-version"
+        }
+      ]
+    },
+    "retainKeysMergeItem": {
+      "description": "RetainKeysMergeItem is type definition for testing strategic merge.",
+      "required": [],
+      "properties": {
+        "name": {
+          "description": "Name field.",
+          "type": "string"
+        },
+        "value": {
+          "description": "Value field.",
+          "type": "string"
+        },
+        "other": {
+          "description": "Other field.",
+          "type": "string"
+        },
+        "simpleMap": {
+          "description": "SimpleMap field.",
+          "additionalProperties": "object",
+          "items": {
+            "type": "string"
+          }
+        },
+        "mergingList": {
+          "description": "MergingList field.",
+          "type": "array",
+          "items": {
+            "$ref": "#/definitions/mergeItem"
+          },
+          "x-kubernetes-patch-merge-key": "name",
+          "x-kubernetes-patch-strategy": "merge"
+        },
+        "nonMergingList": {
+          "description": "NonMergingList field.",
+          "type": "array",
+          "items": {
+            "$ref": "#/definitions/mergeItem"
+          }
+        },
+        "mergingIntList": {
+          "description": "MergingIntList field.",
+          "type": "array",
+          "items": {
+            "type": "integer",
+            "format": "int32"
+          },
+          "x-kubernetes-patch-strategy": "merge"
+        }
+      },
+      "x-kubernetes-group-version-kind": [
+        {
+          "group": "fake-group",
+          "kind": "retainKeysMergeItem",
+          "version": "some-version"
+        }
+      ]
+    },
+    "io.k8s.apimachinery.pkg.runtime.RawExtension": {
+      "description": "RawExtension is used to hold extensions in external versions.",
+      "required": [
+        "Raw"
+      ],
+      "properties": {
+        "Raw": {
+          "description": "Raw is the underlying serialization of this object.",
+          "type": "string",
+          "format": "byte"
+        }
+      }
+    }
+  }
+}

vendor/k8s.io/apimachinery/pkg/util/strategicpatch/testdata/swagger-precision-item.json

@@ -0,0 +1,47 @@
+{
+  "swagger": "2.0",
+  "info": {
+    "title": "StrategicMergePatchTestingPrecisionItem",
+    "version": "v1.9.0"
+  },
+  "paths": {},
+  "definitions": {
+    "precisionItem": {
+      "description": "PrecisionItem is type definition for testing strategic merge.",
+      "required": [],
+      "properties": {
+        "name": {
+          "description": "Name field.",
+          "type": "string"
+        },
+        "int32": {
+          "description": "Int32 field.",
+          "type": "integer",
+          "format": "int32"
+        },
+        "int64": {
+          "description": "Int64 field.",
+          "type": "integer",
+          "format": "int64"
+        },
+        "float32": {
+          "description": "Float32 field.",
+          "type": "number",
+          "format": "float32"
+        },
+        "float64": {
+          "description": "Float64 field.",
+          "type": "number",
+          "format": "float64"
+        }
+      },
+      "x-kubernetes-group-version-kind": [
+        {
+          "group": "fake-group",
+          "kind": "precisionItem",
+          "version": "some-version"
+        }
+      ]
+    }
+  }
+}

vendor/k8s.io/apimachinery/pkg/util/strategicpatch/testing/BUILD

@@ -0,0 +1,30 @@
+package(default_visibility = ["//visibility:public"])
+
+load("@io_bazel_rules_go//go:def.bzl", "go_library")
+
+go_library(
+    name = "go_default_library",
+    srcs = ["openapi.go"],
+    importpath = "k8s.io/apimachinery/pkg/util/strategicpatch/testing",
+    visibility = ["//visibility:public"],
+    deps = [
+        "//vendor/github.com/googleapis/gnostic/OpenAPIv2:go_default_library",
+        "//vendor/github.com/googleapis/gnostic/compiler:go_default_library",
+        "//vendor/gopkg.in/yaml.v2:go_default_library",
+        "//vendor/k8s.io/kube-openapi/pkg/util/proto:go_default_library",
+    ],
+)
+
+filegroup(
+    name = "package-srcs",
+    srcs = glob(["**"]),
+    tags = ["automanaged"],
+    visibility = ["//visibility:private"],
+)
+
+filegroup(
+    name = "all-srcs",
+    srcs = [":package-srcs"],
+    tags = ["automanaged"],
+    visibility = ["//visibility:public"],
+)

vendor/k8s.io/apimachinery/pkg/util/strategicpatch/testing/openapi.go

@@ -0,0 +1,84 @@
+/*
+Copyright 2017 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package testing
+
+import (
+	"io/ioutil"
+	"os"
+	"sync"
+
+	"gopkg.in/yaml.v2"
+
+	"github.com/googleapis/gnostic/OpenAPIv2"
+	"github.com/googleapis/gnostic/compiler"
+	openapi "k8s.io/kube-openapi/pkg/util/proto"
+)
+
+// Fake opens and returns a openapi swagger from a file Path. It will
+// parse only once and then return the same copy everytime.
+type Fake struct {
+	Path string
+
+	once     sync.Once
+	document *openapi_v2.Document
+	err      error
+}
+
+// OpenAPISchema returns the openapi document and a potential error.
+func (f *Fake) OpenAPISchema() (*openapi_v2.Document, error) {
+	f.once.Do(func() {
+		_, err := os.Stat(f.Path)
+		if err != nil {
+			f.err = err
+			return
+		}
+		spec, err := ioutil.ReadFile(f.Path)
+		if err != nil {
+			f.err = err
+			return
+		}
+		var info yaml.MapSlice
+		err = yaml.Unmarshal(spec, &info)
+		if err != nil {
+			f.err = err
+			return
+		}
+		f.document, f.err = openapi_v2.NewDocument(info, compiler.NewContext("$root", nil))
+	})
+	return f.document, f.err
+}
+
+func getSchema(f Fake, model string) (openapi.Schema, error) {
+	s, err := f.OpenAPISchema()
+	if err != nil {
+		return nil, err
+	}
+	m, err := openapi.NewOpenAPIData(s)
+	if err != nil {
+		return nil, err
+	}
+	return m.LookupModel(model), nil
+}
+
+// GetSchemaOrDie returns returns the openapi schema.
+func GetSchemaOrDie(f Fake, model string) openapi.Schema {
+	s, err := getSchema(f, model)
+	if err != nil {
+		panic(err)
+	}
+	return s
+}

vendor/k8s.io/apimachinery/pkg/util/strategicpatch/types.go

@@ -0,0 +1,193 @@
+/*
+Copyright 2017 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package strategicpatch
+
+import (
+	"errors"
+	"strings"
+
+	"k8s.io/apimachinery/pkg/util/mergepatch"
+	openapi "k8s.io/kube-openapi/pkg/util/proto"
+)
+
+const (
+	patchStrategyOpenapiextensionKey = "x-kubernetes-patch-strategy"
+	patchMergeKeyOpenapiextensionKey = "x-kubernetes-patch-merge-key"
+)
+
+type LookupPatchItem interface {
+	openapi.SchemaVisitor
+
+	Error() error
+	Path() *openapi.Path
+}
+
+type kindItem struct {
+	key          string
+	path         *openapi.Path
+	err          error
+	patchmeta    PatchMeta
+	subschema    openapi.Schema
+	hasVisitKind bool
+}
+
+func NewKindItem(key string, path *openapi.Path) *kindItem {
+	return &kindItem{
+		key:  key,
+		path: path,
+	}
+}
+
+var _ LookupPatchItem = &kindItem{}
+
+func (item *kindItem) Error() error {
+	return item.err
+}
+
+func (item *kindItem) Path() *openapi.Path {
+	return item.path
+}
+
+func (item *kindItem) VisitPrimitive(schema *openapi.Primitive) {
+	item.err = errors.New("expected kind, but got primitive")
+}
+
+func (item *kindItem) VisitArray(schema *openapi.Array) {
+	item.err = errors.New("expected kind, but got slice")
+}
+
+func (item *kindItem) VisitMap(schema *openapi.Map) {
+	item.err = errors.New("expected kind, but got map")
+}
+
+func (item *kindItem) VisitReference(schema openapi.Reference) {
+	if !item.hasVisitKind {
+		schema.SubSchema().Accept(item)
+	}
+}
+
+func (item *kindItem) VisitKind(schema *openapi.Kind) {
+	subschema, ok := schema.Fields[item.key]
+	if !ok {
+		item.err = FieldNotFoundError{Path: schema.GetPath().String(), Field: item.key}
+		return
+	}
+
+	mergeKey, patchStrategies, err := parsePatchMetadata(subschema.GetExtensions())
+	if err != nil {
+		item.err = err
+		return
+	}
+	item.patchmeta = PatchMeta{
+		patchStrategies: patchStrategies,
+		patchMergeKey:   mergeKey,
+	}
+	item.subschema = subschema
+}
+
+type sliceItem struct {
+	key          string
+	path         *openapi.Path
+	err          error
+	patchmeta    PatchMeta
+	subschema    openapi.Schema
+	hasVisitKind bool
+}
+
+func NewSliceItem(key string, path *openapi.Path) *sliceItem {
+	return &sliceItem{
+		key:  key,
+		path: path,
+	}
+}
+
+var _ LookupPatchItem = &sliceItem{}
+
+func (item *sliceItem) Error() error {
+	return item.err
+}
+
+func (item *sliceItem) Path() *openapi.Path {
+	return item.path
+}
+
+func (item *sliceItem) VisitPrimitive(schema *openapi.Primitive) {
+	item.err = errors.New("expected slice, but got primitive")
+}
+
+func (item *sliceItem) VisitArray(schema *openapi.Array) {
+	if !item.hasVisitKind {
+		item.err = errors.New("expected visit kind first, then visit array")
+	}
+	subschema := schema.SubType
+	item.subschema = subschema
+}
+
+func (item *sliceItem) VisitMap(schema *openapi.Map) {
+	item.err = errors.New("expected slice, but got map")
+}
+
+func (item *sliceItem) VisitReference(schema openapi.Reference) {
+	if !item.hasVisitKind {
+		schema.SubSchema().Accept(item)
+	} else {
+		item.subschema = schema.SubSchema()
+	}
+}
+
+func (item *sliceItem) VisitKind(schema *openapi.Kind) {
+	subschema, ok := schema.Fields[item.key]
+	if !ok {
+		item.err = FieldNotFoundError{Path: schema.GetPath().String(), Field: item.key}
+		return
+	}
+
+	mergeKey, patchStrategies, err := parsePatchMetadata(subschema.GetExtensions())
+	if err != nil {
+		item.err = err
+		return
+	}
+	item.patchmeta = PatchMeta{
+		patchStrategies: patchStrategies,
+		patchMergeKey:   mergeKey,
+	}
+	item.hasVisitKind = true
+	subschema.Accept(item)
+}
+
+func parsePatchMetadata(extensions map[string]interface{}) (string, []string, error) {
+	ps, foundPS := extensions[patchStrategyOpenapiextensionKey]
+	var patchStrategies []string
+	var mergeKey, patchStrategy string
+	var ok bool
+	if foundPS {
+		patchStrategy, ok = ps.(string)
+		if ok {
+			patchStrategies = strings.Split(patchStrategy, ",")
+		} else {
+			return "", nil, mergepatch.ErrBadArgType(patchStrategy, ps)
+		}
+	}
+	mk, foundMK := extensions[patchMergeKeyOpenapiextensionKey]
+	if foundMK {
+		mergeKey, ok = mk.(string)
+		if !ok {
+			return "", nil, mergepatch.ErrBadArgType(mergeKey, mk)
+		}
+	}
+	return mergeKey, patchStrategies, nil
+}