vendorify
diff --git a/go/vendor/github.com/go-openapi/spec/expander.go b/go/vendor/github.com/go-openapi/spec/expander.go
new file mode 100644
index 0000000..456a9dd
--- /dev/null
+++ b/go/vendor/github.com/go-openapi/spec/expander.go
@@ -0,0 +1,1227 @@
+// Copyright 2015 go-swagger maintainers
+//
+// 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 spec
+
+import (
+	"encoding/json"
+	"fmt"
+	"log"
+	"net/url"
+	"os"
+	"path"
+	"path/filepath"
+	"reflect"
+	"strings"
+	"sync"
+
+	"github.com/go-openapi/jsonpointer"
+	"github.com/go-openapi/swag"
+)
+
+// ExpandOptions provides options for expand.
+type ExpandOptions struct {
+	RelativeBase        string
+	SkipSchemas         bool
+	ContinueOnError     bool
+	AbsoluteCircularRef bool
+}
+
+// ResolutionCache a cache for resolving urls
+type ResolutionCache interface {
+	Get(string) (interface{}, bool)
+	Set(string, interface{})
+}
+
+type simpleCache struct {
+	lock  sync.RWMutex
+	store map[string]interface{}
+}
+
+var resCache ResolutionCache
+
+func init() {
+	resCache = initResolutionCache()
+}
+
+// initResolutionCache initializes the URI resolution cache
+func initResolutionCache() ResolutionCache {
+	return &simpleCache{store: map[string]interface{}{
+		"http://swagger.io/v2/schema.json":       MustLoadSwagger20Schema(),
+		"http://json-schema.org/draft-04/schema": MustLoadJSONSchemaDraft04(),
+	}}
+}
+
+// resolverContext allows to share a context during spec processing.
+// At the moment, it just holds the index of circular references found.
+type resolverContext struct {
+	// circulars holds all visited circular references, which allows shortcuts.
+	// NOTE: this is not just a performance improvement: it is required to figure out
+	// circular references which participate several cycles.
+	// This structure is privately instantiated and needs not be locked against
+	// concurrent access, unless we chose to implement a parallel spec walking.
+	circulars map[string]bool
+	basePath  string
+}
+
+func newResolverContext(originalBasePath string) *resolverContext {
+	return &resolverContext{
+		circulars: make(map[string]bool),
+		basePath:  originalBasePath, // keep the root base path in context
+	}
+}
+
+// Get retrieves a cached URI
+func (s *simpleCache) Get(uri string) (interface{}, bool) {
+	debugLog("getting %q from resolution cache", uri)
+	s.lock.RLock()
+	v, ok := s.store[uri]
+	debugLog("got %q from resolution cache: %t", uri, ok)
+
+	s.lock.RUnlock()
+	return v, ok
+}
+
+// Set caches a URI
+func (s *simpleCache) Set(uri string, data interface{}) {
+	s.lock.Lock()
+	s.store[uri] = data
+	s.lock.Unlock()
+}
+
+// ResolveRefWithBase resolves a reference against a context root with preservation of base path
+func ResolveRefWithBase(root interface{}, ref *Ref, opts *ExpandOptions) (*Schema, error) {
+	resolver, err := defaultSchemaLoader(root, opts, nil, nil)
+	if err != nil {
+		return nil, err
+	}
+	specBasePath := ""
+	if opts != nil && opts.RelativeBase != "" {
+		specBasePath, _ = absPath(opts.RelativeBase)
+	}
+
+	result := new(Schema)
+	if err := resolver.Resolve(ref, result, specBasePath); err != nil {
+		return nil, err
+	}
+	return result, nil
+}
+
+// ResolveRef resolves a reference against a context root
+// ref is guaranteed to be in root (no need to go to external files)
+// ResolveRef is ONLY called from the code generation module
+func ResolveRef(root interface{}, ref *Ref) (*Schema, error) {
+	res, _, err := ref.GetPointer().Get(root)
+	if err != nil {
+		panic(err)
+	}
+	switch sch := res.(type) {
+	case Schema:
+		return &sch, nil
+	case *Schema:
+		return sch, nil
+	case map[string]interface{}:
+		b, _ := json.Marshal(sch)
+		newSch := new(Schema)
+		_ = json.Unmarshal(b, newSch)
+		return newSch, nil
+	default:
+		return nil, fmt.Errorf("unknown type for the resolved reference")
+	}
+}
+
+// ResolveParameter resolves a parameter reference against a context root
+func ResolveParameter(root interface{}, ref Ref) (*Parameter, error) {
+	return ResolveParameterWithBase(root, ref, nil)
+}
+
+// ResolveParameterWithBase resolves a parameter reference against a context root and base path
+func ResolveParameterWithBase(root interface{}, ref Ref, opts *ExpandOptions) (*Parameter, error) {
+	resolver, err := defaultSchemaLoader(root, opts, nil, nil)
+	if err != nil {
+		return nil, err
+	}
+
+	result := new(Parameter)
+	if err := resolver.Resolve(&ref, result, ""); err != nil {
+		return nil, err
+	}
+	return result, nil
+}
+
+// ResolveResponse resolves response a reference against a context root
+func ResolveResponse(root interface{}, ref Ref) (*Response, error) {
+	return ResolveResponseWithBase(root, ref, nil)
+}
+
+// ResolveResponseWithBase resolves response a reference against a context root and base path
+func ResolveResponseWithBase(root interface{}, ref Ref, opts *ExpandOptions) (*Response, error) {
+	resolver, err := defaultSchemaLoader(root, opts, nil, nil)
+	if err != nil {
+		return nil, err
+	}
+
+	result := new(Response)
+	if err := resolver.Resolve(&ref, result, ""); err != nil {
+		return nil, err
+	}
+	return result, nil
+}
+
+// ResolveItems resolves header and parameter items reference against a context root and base path
+func ResolveItems(root interface{}, ref Ref, opts *ExpandOptions) (*Items, error) {
+	resolver, err := defaultSchemaLoader(root, opts, nil, nil)
+	if err != nil {
+		return nil, err
+	}
+	basePath := ""
+	if opts.RelativeBase != "" {
+		basePath = opts.RelativeBase
+	}
+	result := new(Items)
+	if err := resolver.Resolve(&ref, result, basePath); err != nil {
+		return nil, err
+	}
+	return result, nil
+}
+
+// ResolvePathItem resolves response a path item against a context root and base path
+func ResolvePathItem(root interface{}, ref Ref, opts *ExpandOptions) (*PathItem, error) {
+	resolver, err := defaultSchemaLoader(root, opts, nil, nil)
+	if err != nil {
+		return nil, err
+	}
+	basePath := ""
+	if opts.RelativeBase != "" {
+		basePath = opts.RelativeBase
+	}
+	result := new(PathItem)
+	if err := resolver.Resolve(&ref, result, basePath); err != nil {
+		return nil, err
+	}
+	return result, nil
+}
+
+type schemaLoader struct {
+	root    interface{}
+	options *ExpandOptions
+	cache   ResolutionCache
+	context *resolverContext
+	loadDoc func(string) (json.RawMessage, error)
+}
+
+var idPtr, _ = jsonpointer.New("/id")
+var refPtr, _ = jsonpointer.New("/$ref")
+
+// PathLoader function to use when loading remote refs
+var PathLoader func(string) (json.RawMessage, error)
+
+func init() {
+	PathLoader = func(path string) (json.RawMessage, error) {
+		data, err := swag.LoadFromFileOrHTTP(path)
+		if err != nil {
+			return nil, err
+		}
+		return json.RawMessage(data), nil
+	}
+}
+
+func defaultSchemaLoader(
+	root interface{},
+	expandOptions *ExpandOptions,
+	cache ResolutionCache,
+	context *resolverContext) (*schemaLoader, error) {
+
+	if cache == nil {
+		cache = resCache
+	}
+	if expandOptions == nil {
+		expandOptions = &ExpandOptions{}
+	}
+	absBase, _ := absPath(expandOptions.RelativeBase)
+	if context == nil {
+		context = newResolverContext(absBase)
+	}
+	return &schemaLoader{
+		root:    root,
+		options: expandOptions,
+		cache:   cache,
+		context: context,
+		loadDoc: func(path string) (json.RawMessage, error) {
+			debugLog("fetching document at %q", path)
+			return PathLoader(path)
+		},
+	}, nil
+}
+
+func idFromNode(node interface{}) (*Ref, error) {
+	if idValue, _, err := idPtr.Get(node); err == nil {
+		if refStr, ok := idValue.(string); ok && refStr != "" {
+			idRef, err := NewRef(refStr)
+			if err != nil {
+				return nil, err
+			}
+			return &idRef, nil
+		}
+	}
+	return nil, nil
+}
+
+func nextRef(startingNode interface{}, startingRef *Ref, ptr *jsonpointer.Pointer) *Ref {
+	if startingRef == nil {
+		return nil
+	}
+
+	if ptr == nil {
+		return startingRef
+	}
+
+	ret := startingRef
+	var idRef *Ref
+	node := startingNode
+
+	for _, tok := range ptr.DecodedTokens() {
+		node, _, _ = jsonpointer.GetForToken(node, tok)
+		if node == nil {
+			break
+		}
+
+		idRef, _ = idFromNode(node)
+		if idRef != nil {
+			nw, err := ret.Inherits(*idRef)
+			if err != nil {
+				break
+			}
+			ret = nw
+		}
+
+		refRef, _, _ := refPtr.Get(node)
+		if refRef != nil {
+			var rf Ref
+			switch value := refRef.(type) {
+			case string:
+				rf, _ = NewRef(value)
+			}
+			nw, err := ret.Inherits(rf)
+			if err != nil {
+				break
+			}
+			nwURL := nw.GetURL()
+			if nwURL.Scheme == "file" || (nwURL.Scheme == "" && nwURL.Host == "") {
+				nwpt := filepath.ToSlash(nwURL.Path)
+				if filepath.IsAbs(nwpt) {
+					_, err := os.Stat(nwpt)
+					if err != nil {
+						nwURL.Path = filepath.Join(".", nwpt)
+					}
+				}
+			}
+
+			ret = nw
+		}
+
+	}
+
+	return ret
+}
+
+// normalize absolute path for cache.
+// on Windows, drive letters should be converted to lower as scheme in net/url.URL
+func normalizeAbsPath(path string) string {
+	u, err := url.Parse(path)
+	if err != nil {
+		debugLog("normalize absolute path failed: %s", err)
+		return path
+	}
+	return u.String()
+}
+
+// base or refPath could be a file path or a URL
+// given a base absolute path and a ref path, return the absolute path of refPath
+// 1) if refPath is absolute, return it
+// 2) if refPath is relative, join it with basePath keeping the scheme, hosts, and ports if exists
+// base could be a directory or a full file path
+func normalizePaths(refPath, base string) string {
+	refURL, _ := url.Parse(refPath)
+	if path.IsAbs(refURL.Path) || filepath.IsAbs(refPath) {
+		// refPath is actually absolute
+		if refURL.Host != "" {
+			return refPath
+		}
+		parts := strings.Split(refPath, "#")
+		result := filepath.FromSlash(parts[0])
+		if len(parts) == 2 {
+			result += "#" + parts[1]
+		}
+		return result
+	}
+
+	// relative refPath
+	baseURL, _ := url.Parse(base)
+	if !strings.HasPrefix(refPath, "#") {
+		// combining paths
+		if baseURL.Host != "" {
+			baseURL.Path = path.Join(path.Dir(baseURL.Path), refURL.Path)
+		} else { // base is a file
+			newBase := fmt.Sprintf("%s#%s", filepath.Join(filepath.Dir(base), filepath.FromSlash(refURL.Path)), refURL.Fragment)
+			return newBase
+		}
+
+	}
+	// copying fragment from ref to base
+	baseURL.Fragment = refURL.Fragment
+	return baseURL.String()
+}
+
+// denormalizePaths returns to simplest notation on file $ref,
+// i.e. strips the absolute path and sets a path relative to the base path.
+//
+// This is currently used when we rewrite ref after a circular ref has been detected
+func denormalizeFileRef(ref *Ref, relativeBase, originalRelativeBase string) *Ref {
+	debugLog("denormalizeFileRef for: %s", ref.String())
+
+	if ref.String() == "" || ref.IsRoot() || ref.HasFragmentOnly {
+		return ref
+	}
+	// strip relativeBase from URI
+	relativeBaseURL, _ := url.Parse(relativeBase)
+	relativeBaseURL.Fragment = ""
+
+	if relativeBaseURL.IsAbs() && strings.HasPrefix(ref.String(), relativeBase) {
+		// this should work for absolute URI (e.g. http://...): we have an exact match, just trim prefix
+		r, _ := NewRef(strings.TrimPrefix(ref.String(), relativeBase))
+		return &r
+	}
+
+	if relativeBaseURL.IsAbs() {
+		// other absolute URL get unchanged (i.e. with a non-empty scheme)
+		return ref
+	}
+
+	// for relative file URIs:
+	originalRelativeBaseURL, _ := url.Parse(originalRelativeBase)
+	originalRelativeBaseURL.Fragment = ""
+	if strings.HasPrefix(ref.String(), originalRelativeBaseURL.String()) {
+		// the resulting ref is in the expanded spec: return a local ref
+		r, _ := NewRef(strings.TrimPrefix(ref.String(), originalRelativeBaseURL.String()))
+		return &r
+	}
+
+	// check if we may set a relative path, considering the original base path for this spec.
+	// Example:
+	//   spec is located at /mypath/spec.json
+	//   my normalized ref points to: /mypath/item.json#/target
+	//   expected result: item.json#/target
+	parts := strings.Split(ref.String(), "#")
+	relativePath, err := filepath.Rel(path.Dir(originalRelativeBaseURL.String()), parts[0])
+	if err != nil {
+		// there is no common ancestor (e.g. different drives on windows)
+		// leaves the ref unchanged
+		return ref
+	}
+	if len(parts) == 2 {
+		relativePath += "#" + parts[1]
+	}
+	r, _ := NewRef(relativePath)
+	return &r
+}
+
+// relativeBase could be an ABSOLUTE file path or an ABSOLUTE URL
+func normalizeFileRef(ref *Ref, relativeBase string) *Ref {
+	// This is important for when the reference is pointing to the root schema
+	if ref.String() == "" {
+		r, _ := NewRef(relativeBase)
+		return &r
+	}
+
+	debugLog("normalizing %s against %s", ref.String(), relativeBase)
+
+	s := normalizePaths(ref.String(), relativeBase)
+	r, _ := NewRef(s)
+	return &r
+}
+
+func (r *schemaLoader) resolveRef(ref *Ref, target interface{}, basePath string) error {
+	tgt := reflect.ValueOf(target)
+	if tgt.Kind() != reflect.Ptr {
+		return fmt.Errorf("resolve ref: target needs to be a pointer")
+	}
+
+	refURL := ref.GetURL()
+	if refURL == nil {
+		return nil
+	}
+
+	var res interface{}
+	var data interface{}
+	var err error
+	// Resolve against the root if it isn't nil, and if ref is pointing at the root, or has a fragment only which means
+	// it is pointing somewhere in the root.
+	root := r.root
+	if (ref.IsRoot() || ref.HasFragmentOnly) && root == nil && basePath != "" {
+		if baseRef, erb := NewRef(basePath); erb == nil {
+			root, _, _, _ = r.load(baseRef.GetURL())
+		}
+	}
+	if (ref.IsRoot() || ref.HasFragmentOnly) && root != nil {
+		data = root
+	} else {
+		baseRef := normalizeFileRef(ref, basePath)
+		debugLog("current ref is: %s", ref.String())
+		debugLog("current ref normalized file: %s", baseRef.String())
+		data, _, _, err = r.load(baseRef.GetURL())
+		if err != nil {
+			return err
+		}
+	}
+
+	res = data
+	if ref.String() != "" {
+		res, _, err = ref.GetPointer().Get(data)
+		if err != nil {
+			return err
+		}
+	}
+	if err := swag.DynamicJSONToStruct(res, target); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func (r *schemaLoader) load(refURL *url.URL) (interface{}, url.URL, bool, error) {
+	debugLog("loading schema from url: %s", refURL)
+	toFetch := *refURL
+	toFetch.Fragment = ""
+
+	normalized := normalizeAbsPath(toFetch.String())
+
+	data, fromCache := r.cache.Get(normalized)
+	if !fromCache {
+		b, err := r.loadDoc(normalized)
+		if err != nil {
+			return nil, url.URL{}, false, err
+		}
+
+		if err := json.Unmarshal(b, &data); err != nil {
+			return nil, url.URL{}, false, err
+		}
+		r.cache.Set(normalized, data)
+	}
+
+	return data, toFetch, fromCache, nil
+}
+
+// Resolve resolves a reference against basePath and stores the result in target
+// Resolve is not in charge of following references, it only resolves ref by following its URL
+// if the schema that ref is referring to has more refs in it. Resolve doesn't resolve them
+// if basePath is an empty string, ref is resolved against the root schema stored in the schemaLoader struct
+func (r *schemaLoader) Resolve(ref *Ref, target interface{}, basePath string) error {
+	return r.resolveRef(ref, target, basePath)
+}
+
+// absPath returns the absolute path of a file
+func absPath(fname string) (string, error) {
+	if strings.HasPrefix(fname, "http") {
+		return fname, nil
+	}
+	if filepath.IsAbs(fname) {
+		return fname, nil
+	}
+	wd, err := os.Getwd()
+	return filepath.Join(wd, fname), err
+}
+
+// ExpandSpec expands the references in a swagger spec
+func ExpandSpec(spec *Swagger, options *ExpandOptions) error {
+	resolver, err := defaultSchemaLoader(spec, options, nil, nil)
+	// Just in case this ever returns an error.
+	if shouldStopOnError(err, resolver.options) {
+		return err
+	}
+
+	// getting the base path of the spec to adjust all subsequent reference resolutions
+	specBasePath := ""
+	if options != nil && options.RelativeBase != "" {
+		specBasePath, _ = absPath(options.RelativeBase)
+	}
+
+	if options == nil || !options.SkipSchemas {
+		for key, definition := range spec.Definitions {
+			var def *Schema
+			var err error
+			if def, err = expandSchema(definition, []string{fmt.Sprintf("#/definitions/%s", key)}, resolver, specBasePath); shouldStopOnError(err, resolver.options) {
+				return err
+			}
+			if def != nil {
+				spec.Definitions[key] = *def
+			}
+		}
+	}
+
+	for key, parameter := range spec.Parameters {
+		if err := expandParameter(&parameter, resolver, specBasePath); shouldStopOnError(err, resolver.options) {
+			return err
+		}
+		spec.Parameters[key] = parameter
+	}
+
+	for key, response := range spec.Responses {
+		if err := expandResponse(&response, resolver, specBasePath); shouldStopOnError(err, resolver.options) {
+			return err
+		}
+		spec.Responses[key] = response
+	}
+
+	if spec.Paths != nil {
+		for key, path := range spec.Paths.Paths {
+			if err := expandPathItem(&path, resolver, specBasePath); shouldStopOnError(err, resolver.options) {
+				return err
+			}
+			spec.Paths.Paths[key] = path
+		}
+	}
+
+	return nil
+}
+
+func shouldStopOnError(err error, opts *ExpandOptions) bool {
+	if err != nil && !opts.ContinueOnError {
+		return true
+	}
+
+	if err != nil {
+		log.Println(err)
+	}
+
+	return false
+}
+
+// baseForRoot loads in the cache the root document and produces a fake "root" base path entry
+// for further $ref resolution
+func baseForRoot(root interface{}, cache ResolutionCache) string {
+	// cache the root document to resolve $ref's
+	const rootBase = "root"
+	if root != nil {
+		base, _ := absPath(rootBase)
+		normalizedBase := normalizeAbsPath(base)
+		debugLog("setting root doc in cache at: %s", normalizedBase)
+		if cache == nil {
+			cache = resCache
+		}
+		cache.Set(normalizedBase, root)
+		return rootBase
+	}
+	return ""
+}
+
+// ExpandSchema expands the refs in the schema object with reference to the root object
+// go-openapi/validate uses this function
+// notice that it is impossible to reference a json schema in a different file other than root
+func ExpandSchema(schema *Schema, root interface{}, cache ResolutionCache) error {
+	opts := &ExpandOptions{
+		// when a root is specified, cache the root as an in-memory document for $ref retrieval
+		RelativeBase:    baseForRoot(root, cache),
+		SkipSchemas:     false,
+		ContinueOnError: false,
+		// when no base path is specified, remaining $ref (circular) are rendered with an absolute path
+		AbsoluteCircularRef: true,
+	}
+	return ExpandSchemaWithBasePath(schema, cache, opts)
+}
+
+// ExpandSchemaWithBasePath expands the refs in the schema object, base path configured through expand options
+func ExpandSchemaWithBasePath(schema *Schema, cache ResolutionCache, opts *ExpandOptions) error {
+	if schema == nil {
+		return nil
+	}
+
+	var basePath string
+	if opts.RelativeBase != "" {
+		basePath, _ = absPath(opts.RelativeBase)
+	}
+
+	resolver, err := defaultSchemaLoader(nil, opts, cache, nil)
+	if err != nil {
+		return err
+	}
+
+	refs := []string{""}
+	var s *Schema
+	if s, err = expandSchema(*schema, refs, resolver, basePath); err != nil {
+		return err
+	}
+	*schema = *s
+	return nil
+}
+
+func expandItems(target Schema, parentRefs []string, resolver *schemaLoader, basePath string) (*Schema, error) {
+	if target.Items != nil {
+		if target.Items.Schema != nil {
+			t, err := expandSchema(*target.Items.Schema, parentRefs, resolver, basePath)
+			if err != nil {
+				return nil, err
+			}
+			*target.Items.Schema = *t
+		}
+		for i := range target.Items.Schemas {
+			t, err := expandSchema(target.Items.Schemas[i], parentRefs, resolver, basePath)
+			if err != nil {
+				return nil, err
+			}
+			target.Items.Schemas[i] = *t
+		}
+	}
+	return &target, nil
+}
+
+// basePathFromSchemaID returns a new basePath based on an existing basePath and a schema ID
+func basePathFromSchemaID(oldBasePath, id string) string {
+	u, err := url.Parse(oldBasePath)
+	if err != nil {
+		panic(err)
+	}
+	uid, err := url.Parse(id)
+	if err != nil {
+		panic(err)
+	}
+
+	if path.IsAbs(uid.Path) {
+		return id
+	}
+	u.Path = path.Join(path.Dir(u.Path), uid.Path)
+	return u.String()
+}
+
+// isCircular detects cycles in sequences of $ref.
+// It relies on a private context (which needs not be locked).
+func (r *schemaLoader) isCircular(ref *Ref, basePath string, parentRefs ...string) (foundCycle bool) {
+	normalizedRef := normalizePaths(ref.String(), basePath)
+	if _, ok := r.context.circulars[normalizedRef]; ok {
+		// circular $ref has been already detected in another explored cycle
+		foundCycle = true
+		return
+	}
+	foundCycle = swag.ContainsStringsCI(parentRefs, normalizedRef)
+	if foundCycle {
+		r.context.circulars[normalizedRef] = true
+	}
+	return
+}
+
+func updateBasePath(transitive *schemaLoader, resolver *schemaLoader, basePath string) string {
+	if transitive != resolver {
+		debugLog("got a new resolver")
+		if transitive.options != nil && transitive.options.RelativeBase != "" {
+			basePath, _ = absPath(transitive.options.RelativeBase)
+			debugLog("new basePath = %s", basePath)
+		}
+	}
+
+	return basePath
+}
+
+func expandSchema(target Schema, parentRefs []string, resolver *schemaLoader, basePath string) (*Schema, error) {
+	if target.Ref.String() == "" && target.Ref.IsRoot() {
+		// normalizing is important
+		newRef := normalizeFileRef(&target.Ref, basePath)
+		target.Ref = *newRef
+		return &target, nil
+
+	}
+
+	/* change the base path of resolution when an ID is encountered
+	   otherwise the basePath should inherit the parent's */
+	// important: ID can be relative path
+	if target.ID != "" {
+		debugLog("schema has ID: %s", target.ID)
+		// handling the case when id is a folder
+		// remember that basePath has to be a file
+		refPath := target.ID
+		if strings.HasSuffix(target.ID, "/") {
+			// path.Clean here would not work correctly if basepath is http
+			refPath = fmt.Sprintf("%s%s", refPath, "placeholder.json")
+		}
+		basePath = normalizePaths(refPath, basePath)
+	}
+
+	/* Explain here what this function does */
+	var t *Schema
+	/* if Ref is found, everything else doesn't matter */
+	/* Ref also changes the resolution scope of children expandSchema */
+	if target.Ref.String() != "" {
+		/* Here the resolution scope is changed because a $ref was encountered */
+		normalizedRef := normalizeFileRef(&target.Ref, basePath)
+		normalizedBasePath := normalizedRef.RemoteURI()
+
+		if resolver.isCircular(normalizedRef, basePath, parentRefs...) {
+			// this means there is a cycle in the recursion tree: return the Ref
+			// - circular refs cannot be expanded. We leave them as ref.
+			// - denormalization means that a new local file ref is set relative to the original basePath
+			debugLog("shortcut circular ref: basePath: %s, normalizedPath: %s, normalized ref: %s",
+				basePath, normalizedBasePath, normalizedRef.String())
+			if !resolver.options.AbsoluteCircularRef {
+				target.Ref = *denormalizeFileRef(normalizedRef, normalizedBasePath, resolver.context.basePath)
+			} else {
+				target.Ref = *normalizedRef
+			}
+			return &target, nil
+		}
+
+		debugLog("basePath: %s", basePath)
+		if Debug {
+			b, _ := json.Marshal(target)
+			debugLog("calling Resolve with target: %s", string(b))
+		}
+		if err := resolver.Resolve(&target.Ref, &t, basePath); shouldStopOnError(err, resolver.options) {
+			return nil, err
+		}
+
+		if t != nil {
+			parentRefs = append(parentRefs, normalizedRef.String())
+			var err error
+			transitiveResolver, err := transitiveResolver(basePath, target.Ref, resolver)
+			if shouldStopOnError(err, resolver.options) {
+				return nil, err
+			}
+
+			basePath = updateBasePath(transitiveResolver, resolver, normalizedBasePath)
+
+			return expandSchema(*t, parentRefs, transitiveResolver, basePath)
+		}
+	}
+
+	t, err := expandItems(target, parentRefs, resolver, basePath)
+	if shouldStopOnError(err, resolver.options) {
+		return &target, err
+	}
+	if t != nil {
+		target = *t
+	}
+
+	for i := range target.AllOf {
+		t, err := expandSchema(target.AllOf[i], parentRefs, resolver, basePath)
+		if shouldStopOnError(err, resolver.options) {
+			return &target, err
+		}
+		target.AllOf[i] = *t
+	}
+	for i := range target.AnyOf {
+		t, err := expandSchema(target.AnyOf[i], parentRefs, resolver, basePath)
+		if shouldStopOnError(err, resolver.options) {
+			return &target, err
+		}
+		target.AnyOf[i] = *t
+	}
+	for i := range target.OneOf {
+		t, err := expandSchema(target.OneOf[i], parentRefs, resolver, basePath)
+		if shouldStopOnError(err, resolver.options) {
+			return &target, err
+		}
+		if t != nil {
+			target.OneOf[i] = *t
+		}
+	}
+	if target.Not != nil {
+		t, err := expandSchema(*target.Not, parentRefs, resolver, basePath)
+		if shouldStopOnError(err, resolver.options) {
+			return &target, err
+		}
+		if t != nil {
+			*target.Not = *t
+		}
+	}
+	for k := range target.Properties {
+		t, err := expandSchema(target.Properties[k], parentRefs, resolver, basePath)
+		if shouldStopOnError(err, resolver.options) {
+			return &target, err
+		}
+		if t != nil {
+			target.Properties[k] = *t
+		}
+	}
+	if target.AdditionalProperties != nil && target.AdditionalProperties.Schema != nil {
+		t, err := expandSchema(*target.AdditionalProperties.Schema, parentRefs, resolver, basePath)
+		if shouldStopOnError(err, resolver.options) {
+			return &target, err
+		}
+		if t != nil {
+			*target.AdditionalProperties.Schema = *t
+		}
+	}
+	for k := range target.PatternProperties {
+		t, err := expandSchema(target.PatternProperties[k], parentRefs, resolver, basePath)
+		if shouldStopOnError(err, resolver.options) {
+			return &target, err
+		}
+		if t != nil {
+			target.PatternProperties[k] = *t
+		}
+	}
+	for k := range target.Dependencies {
+		if target.Dependencies[k].Schema != nil {
+			t, err := expandSchema(*target.Dependencies[k].Schema, parentRefs, resolver, basePath)
+			if shouldStopOnError(err, resolver.options) {
+				return &target, err
+			}
+			if t != nil {
+				*target.Dependencies[k].Schema = *t
+			}
+		}
+	}
+	if target.AdditionalItems != nil && target.AdditionalItems.Schema != nil {
+		t, err := expandSchema(*target.AdditionalItems.Schema, parentRefs, resolver, basePath)
+		if shouldStopOnError(err, resolver.options) {
+			return &target, err
+		}
+		if t != nil {
+			*target.AdditionalItems.Schema = *t
+		}
+	}
+	for k := range target.Definitions {
+		t, err := expandSchema(target.Definitions[k], parentRefs, resolver, basePath)
+		if shouldStopOnError(err, resolver.options) {
+			return &target, err
+		}
+		if t != nil {
+			target.Definitions[k] = *t
+		}
+	}
+	return &target, nil
+}
+
+func derefPathItem(pathItem *PathItem, parentRefs []string, resolver *schemaLoader, basePath string) error {
+	curRef := pathItem.Ref.String()
+	if curRef != "" {
+		normalizedRef := normalizeFileRef(&pathItem.Ref, basePath)
+		normalizedBasePath := normalizedRef.RemoteURI()
+
+		if resolver.isCircular(normalizedRef, basePath, parentRefs...) {
+			return nil
+		}
+
+		if err := resolver.Resolve(&pathItem.Ref, pathItem, basePath); shouldStopOnError(err, resolver.options) {
+			return err
+		}
+
+		if pathItem.Ref.String() != "" && pathItem.Ref.String() != curRef && basePath != normalizedBasePath {
+			parentRefs = append(parentRefs, normalizedRef.String())
+			return derefPathItem(pathItem, parentRefs, resolver, normalizedBasePath)
+		}
+	}
+
+	return nil
+}
+
+func expandPathItem(pathItem *PathItem, resolver *schemaLoader, basePath string) error {
+	if pathItem == nil {
+		return nil
+	}
+
+	parentRefs := []string{}
+	if err := derefPathItem(pathItem, parentRefs, resolver, basePath); shouldStopOnError(err, resolver.options) {
+		return err
+	}
+	if pathItem.Ref.String() != "" {
+		var err error
+		resolver, err = transitiveResolver(basePath, pathItem.Ref, resolver)
+		if shouldStopOnError(err, resolver.options) {
+			return err
+		}
+	}
+	pathItem.Ref = Ref{}
+
+	// Currently unused:
+	//parentRefs = parentRefs[0:]
+
+	for idx := range pathItem.Parameters {
+		if err := expandParameter(&(pathItem.Parameters[idx]), resolver, basePath); shouldStopOnError(err, resolver.options) {
+			return err
+		}
+	}
+	if err := expandOperation(pathItem.Get, resolver, basePath); shouldStopOnError(err, resolver.options) {
+		return err
+	}
+	if err := expandOperation(pathItem.Head, resolver, basePath); shouldStopOnError(err, resolver.options) {
+		return err
+	}
+	if err := expandOperation(pathItem.Options, resolver, basePath); shouldStopOnError(err, resolver.options) {
+		return err
+	}
+	if err := expandOperation(pathItem.Put, resolver, basePath); shouldStopOnError(err, resolver.options) {
+		return err
+	}
+	if err := expandOperation(pathItem.Post, resolver, basePath); shouldStopOnError(err, resolver.options) {
+		return err
+	}
+	if err := expandOperation(pathItem.Patch, resolver, basePath); shouldStopOnError(err, resolver.options) {
+		return err
+	}
+	if err := expandOperation(pathItem.Delete, resolver, basePath); shouldStopOnError(err, resolver.options) {
+		return err
+	}
+	return nil
+}
+
+func expandOperation(op *Operation, resolver *schemaLoader, basePath string) error {
+	if op == nil {
+		return nil
+	}
+
+	for i, param := range op.Parameters {
+		if err := expandParameter(&param, resolver, basePath); shouldStopOnError(err, resolver.options) {
+			return err
+		}
+		op.Parameters[i] = param
+	}
+
+	if op.Responses != nil {
+		responses := op.Responses
+		if err := expandResponse(responses.Default, resolver, basePath); shouldStopOnError(err, resolver.options) {
+			return err
+		}
+		for code, response := range responses.StatusCodeResponses {
+			if err := expandResponse(&response, resolver, basePath); shouldStopOnError(err, resolver.options) {
+				return err
+			}
+			responses.StatusCodeResponses[code] = response
+		}
+	}
+	return nil
+}
+
+func transitiveResolver(basePath string, ref Ref, resolver *schemaLoader) (*schemaLoader, error) {
+	if ref.IsRoot() || ref.HasFragmentOnly {
+		return resolver, nil
+	}
+
+	baseRef, _ := NewRef(basePath)
+	currentRef := normalizeFileRef(&ref, basePath)
+	// Set a new root to resolve against
+	if !strings.HasPrefix(currentRef.String(), baseRef.String()) {
+		rootURL := currentRef.GetURL()
+		rootURL.Fragment = ""
+		root, _ := resolver.cache.Get(rootURL.String())
+		var err error
+
+		// shallow copy of resolver options to set a new RelativeBase when
+		// traversing multiple documents
+		newOptions := resolver.options
+		newOptions.RelativeBase = rootURL.String()
+		debugLog("setting new root: %s", newOptions.RelativeBase)
+		resolver, err = defaultSchemaLoader(root, newOptions, resolver.cache, resolver.context)
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	return resolver, nil
+}
+
+// ExpandResponseWithRoot expands a response based on a root document, not a fetchable document
+func ExpandResponseWithRoot(response *Response, root interface{}, cache ResolutionCache) error {
+	opts := &ExpandOptions{
+		RelativeBase:    baseForRoot(root, cache),
+		SkipSchemas:     false,
+		ContinueOnError: false,
+		// when no base path is specified, remaining $ref (circular) are rendered with an absolute path
+		AbsoluteCircularRef: true,
+	}
+	resolver, err := defaultSchemaLoader(root, opts, nil, nil)
+	if err != nil {
+		return err
+	}
+
+	return expandResponse(response, resolver, opts.RelativeBase)
+}
+
+// ExpandResponse expands a response based on a basepath
+// This is the exported version of expandResponse
+// all refs inside response will be resolved relative to basePath
+func ExpandResponse(response *Response, basePath string) error {
+	var specBasePath string
+	if basePath != "" {
+		specBasePath, _ = absPath(basePath)
+	}
+	opts := &ExpandOptions{
+		RelativeBase: specBasePath,
+	}
+	resolver, err := defaultSchemaLoader(nil, opts, nil, nil)
+	if err != nil {
+		return err
+	}
+
+	return expandResponse(response, resolver, opts.RelativeBase)
+}
+
+func derefResponse(response *Response, parentRefs []string, resolver *schemaLoader, basePath string) error {
+	curRef := response.Ref.String()
+	if curRef != "" {
+		/* Here the resolution scope is changed because a $ref was encountered */
+		normalizedRef := normalizeFileRef(&response.Ref, basePath)
+		normalizedBasePath := normalizedRef.RemoteURI()
+
+		if resolver.isCircular(normalizedRef, basePath, parentRefs...) {
+			return nil
+		}
+
+		if err := resolver.Resolve(&response.Ref, response, basePath); shouldStopOnError(err, resolver.options) {
+			return err
+		}
+
+		if response.Ref.String() != "" && response.Ref.String() != curRef && basePath != normalizedBasePath {
+			parentRefs = append(parentRefs, normalizedRef.String())
+			return derefResponse(response, parentRefs, resolver, normalizedBasePath)
+		}
+	}
+
+	return nil
+}
+
+func expandResponse(response *Response, resolver *schemaLoader, basePath string) error {
+	if response == nil {
+		return nil
+	}
+	parentRefs := []string{}
+	if err := derefResponse(response, parentRefs, resolver, basePath); shouldStopOnError(err, resolver.options) {
+		return err
+	}
+	if response.Ref.String() != "" {
+		transitiveResolver, err := transitiveResolver(basePath, response.Ref, resolver)
+		if shouldStopOnError(err, transitiveResolver.options) {
+			return err
+		}
+		basePath = updateBasePath(transitiveResolver, resolver, basePath)
+		resolver = transitiveResolver
+	}
+	if response.Schema != nil && response.Schema.Ref.String() != "" {
+		// schema expanded to a $ref in another root
+		var ern error
+		response.Schema.Ref, ern = NewRef(normalizePaths(response.Schema.Ref.String(), response.Ref.RemoteURI()))
+		if ern != nil {
+			return ern
+		}
+	}
+	response.Ref = Ref{}
+
+	parentRefs = parentRefs[0:]
+	if !resolver.options.SkipSchemas && response.Schema != nil {
+		// parentRefs = append(parentRefs, response.Schema.Ref.String())
+		s, err := expandSchema(*response.Schema, parentRefs, resolver, basePath)
+		if shouldStopOnError(err, resolver.options) {
+			return err
+		}
+		*response.Schema = *s
+	}
+
+	return nil
+}
+
+// ExpandParameterWithRoot expands a parameter based on a root document, not a fetchable document
+func ExpandParameterWithRoot(parameter *Parameter, root interface{}, cache ResolutionCache) error {
+	opts := &ExpandOptions{
+		RelativeBase:    baseForRoot(root, cache),
+		SkipSchemas:     false,
+		ContinueOnError: false,
+		// when no base path is specified, remaining $ref (circular) are rendered with an absolute path
+		AbsoluteCircularRef: true,
+	}
+	resolver, err := defaultSchemaLoader(root, opts, nil, nil)
+	if err != nil {
+		return err
+	}
+
+	return expandParameter(parameter, resolver, opts.RelativeBase)
+}
+
+// ExpandParameter expands a parameter based on a basepath
+// This is the exported version of expandParameter
+// all refs inside parameter will be resolved relative to basePath
+func ExpandParameter(parameter *Parameter, basePath string) error {
+	var specBasePath string
+	if basePath != "" {
+		specBasePath, _ = absPath(basePath)
+	}
+	opts := &ExpandOptions{
+		RelativeBase: specBasePath,
+	}
+	resolver, err := defaultSchemaLoader(nil, opts, nil, nil)
+	if err != nil {
+		return err
+	}
+
+	return expandParameter(parameter, resolver, opts.RelativeBase)
+}
+
+func derefParameter(parameter *Parameter, parentRefs []string, resolver *schemaLoader, basePath string) error {
+	curRef := parameter.Ref.String()
+	if curRef != "" {
+		normalizedRef := normalizeFileRef(&parameter.Ref, basePath)
+		normalizedBasePath := normalizedRef.RemoteURI()
+
+		if resolver.isCircular(normalizedRef, basePath, parentRefs...) {
+			return nil
+		}
+
+		if err := resolver.Resolve(&parameter.Ref, parameter, basePath); shouldStopOnError(err, resolver.options) {
+			return err
+		}
+
+		if parameter.Ref.String() != "" && parameter.Ref.String() != curRef && basePath != normalizedBasePath {
+			parentRefs = append(parentRefs, normalizedRef.String())
+			return derefParameter(parameter, parentRefs, resolver, normalizedBasePath)
+		}
+	}
+
+	return nil
+}
+
+func expandParameter(parameter *Parameter, resolver *schemaLoader, basePath string) error {
+	if parameter == nil {
+		return nil
+	}
+
+	parentRefs := []string{}
+	if err := derefParameter(parameter, parentRefs, resolver, basePath); shouldStopOnError(err, resolver.options) {
+		return err
+	}
+	if parameter.Ref.String() != "" {
+		transitiveResolver, err := transitiveResolver(basePath, parameter.Ref, resolver)
+		if shouldStopOnError(err, transitiveResolver.options) {
+			return err
+		}
+		basePath = updateBasePath(transitiveResolver, resolver, basePath)
+		resolver = transitiveResolver
+	}
+
+	if parameter.Schema != nil && parameter.Schema.Ref.String() != "" {
+		// schema expanded to a $ref in another root
+		var ern error
+		parameter.Schema.Ref, ern = NewRef(normalizePaths(parameter.Schema.Ref.String(), parameter.Ref.RemoteURI()))
+		if ern != nil {
+			return ern
+		}
+	}
+	parameter.Ref = Ref{}
+
+	parentRefs = parentRefs[0:]
+	if !resolver.options.SkipSchemas && parameter.Schema != nil {
+		s, err := expandSchema(*parameter.Schema, parentRefs, resolver, basePath)
+		if shouldStopOnError(err, resolver.options) {
+			return err
+		}
+		*parameter.Schema = *s
+	}
+	return nil
+}