From 9aa36a37c73f10bc04bd77edf6e1c2c2a606fe39 Mon Sep 17 00:00:00 2001 From: Alexander Neumann Date: Sun, 19 Aug 2018 13:02:57 +0200 Subject: [PATCH] Vendor cmpopts --- Gopkg.lock | 4 +- .../google/go-cmp/cmp/cmpopts/equate.go | 89 +++++++++ .../google/go-cmp/cmp/cmpopts/ignore.go | 145 ++++++++++++++ .../google/go-cmp/cmp/cmpopts/sort.go | 146 ++++++++++++++ .../google/go-cmp/cmp/cmpopts/sort_go17.go | 46 +++++ .../google/go-cmp/cmp/cmpopts/sort_go18.go | 31 +++ .../go-cmp/cmp/cmpopts/struct_filter.go | 182 ++++++++++++++++++ 7 files changed, 642 insertions(+), 1 deletion(-) create mode 100644 vendor/github.com/google/go-cmp/cmp/cmpopts/equate.go create mode 100644 vendor/github.com/google/go-cmp/cmp/cmpopts/ignore.go create mode 100644 vendor/github.com/google/go-cmp/cmp/cmpopts/sort.go create mode 100644 vendor/github.com/google/go-cmp/cmp/cmpopts/sort_go17.go create mode 100644 vendor/github.com/google/go-cmp/cmp/cmpopts/sort_go18.go create mode 100644 vendor/github.com/google/go-cmp/cmp/cmpopts/struct_filter.go diff --git a/Gopkg.lock b/Gopkg.lock index 6fba8d652..1891a9f94 100644 --- a/Gopkg.lock +++ b/Gopkg.lock @@ -104,10 +104,11 @@ version = "v1.1.0" [[projects]] - digest = "1:2e3c336fc7fde5c984d2841455a658a6d626450b1754a854b3b32e7a8f49a07a" + digest = "1:d2754cafcab0d22c13541618a8029a70a8959eb3525ff201fe971637e2274cd0" name = "github.com/google/go-cmp" packages = [ "cmp", + "cmp/cmpopts", "cmp/internal/diff", "cmp/internal/function", "cmp/internal/value", @@ -449,6 +450,7 @@ "github.com/cenkalti/backoff", "github.com/elithrar/simple-scrypt", "github.com/google/go-cmp/cmp", + "github.com/google/go-cmp/cmp/cmpopts", "github.com/juju/ratelimit", "github.com/kurin/blazer/b2", "github.com/mattn/go-isatty", diff --git a/vendor/github.com/google/go-cmp/cmp/cmpopts/equate.go b/vendor/github.com/google/go-cmp/cmp/cmpopts/equate.go new file mode 100644 index 000000000..41bbddc61 --- /dev/null +++ b/vendor/github.com/google/go-cmp/cmp/cmpopts/equate.go @@ -0,0 +1,89 @@ +// Copyright 2017, The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE.md file. + +// Package cmpopts provides common options for the cmp package. +package cmpopts + +import ( + "math" + "reflect" + + "github.com/google/go-cmp/cmp" +) + +func equateAlways(_, _ interface{}) bool { return true } + +// EquateEmpty returns a Comparer option that determines all maps and slices +// with a length of zero to be equal, regardless of whether they are nil. +// +// EquateEmpty can be used in conjunction with SortSlices and SortMaps. +func EquateEmpty() cmp.Option { + return cmp.FilterValues(isEmpty, cmp.Comparer(equateAlways)) +} + +func isEmpty(x, y interface{}) bool { + vx, vy := reflect.ValueOf(x), reflect.ValueOf(y) + return (x != nil && y != nil && vx.Type() == vy.Type()) && + (vx.Kind() == reflect.Slice || vx.Kind() == reflect.Map) && + (vx.Len() == 0 && vy.Len() == 0) +} + +// EquateApprox returns a Comparer option that determines float32 or float64 +// values to be equal if they are within a relative fraction or absolute margin. +// This option is not used when either x or y is NaN or infinite. +// +// The fraction determines that the difference of two values must be within the +// smaller fraction of the two values, while the margin determines that the two +// values must be within some absolute margin. +// To express only a fraction or only a margin, use 0 for the other parameter. +// The fraction and margin must be non-negative. +// +// The mathematical expression used is equivalent to: +// |x-y| ≤ max(fraction*min(|x|, |y|), margin) +// +// EquateApprox can be used in conjunction with EquateNaNs. +func EquateApprox(fraction, margin float64) cmp.Option { + if margin < 0 || fraction < 0 || math.IsNaN(margin) || math.IsNaN(fraction) { + panic("margin or fraction must be a non-negative number") + } + a := approximator{fraction, margin} + return cmp.Options{ + cmp.FilterValues(areRealF64s, cmp.Comparer(a.compareF64)), + cmp.FilterValues(areRealF32s, cmp.Comparer(a.compareF32)), + } +} + +type approximator struct{ frac, marg float64 } + +func areRealF64s(x, y float64) bool { + return !math.IsNaN(x) && !math.IsNaN(y) && !math.IsInf(x, 0) && !math.IsInf(y, 0) +} +func areRealF32s(x, y float32) bool { + return areRealF64s(float64(x), float64(y)) +} +func (a approximator) compareF64(x, y float64) bool { + relMarg := a.frac * math.Min(math.Abs(x), math.Abs(y)) + return math.Abs(x-y) <= math.Max(a.marg, relMarg) +} +func (a approximator) compareF32(x, y float32) bool { + return a.compareF64(float64(x), float64(y)) +} + +// EquateNaNs returns a Comparer option that determines float32 and float64 +// NaN values to be equal. +// +// EquateNaNs can be used in conjunction with EquateApprox. +func EquateNaNs() cmp.Option { + return cmp.Options{ + cmp.FilterValues(areNaNsF64s, cmp.Comparer(equateAlways)), + cmp.FilterValues(areNaNsF32s, cmp.Comparer(equateAlways)), + } +} + +func areNaNsF64s(x, y float64) bool { + return math.IsNaN(x) && math.IsNaN(y) +} +func areNaNsF32s(x, y float32) bool { + return areNaNsF64s(float64(x), float64(y)) +} diff --git a/vendor/github.com/google/go-cmp/cmp/cmpopts/ignore.go b/vendor/github.com/google/go-cmp/cmp/cmpopts/ignore.go new file mode 100644 index 000000000..e86554b92 --- /dev/null +++ b/vendor/github.com/google/go-cmp/cmp/cmpopts/ignore.go @@ -0,0 +1,145 @@ +// Copyright 2017, The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE.md file. + +package cmpopts + +import ( + "fmt" + "reflect" + "unicode" + "unicode/utf8" + + "github.com/google/go-cmp/cmp" +) + +// IgnoreFields returns an Option that ignores exported fields of the +// given names on a single struct type. +// The struct type is specified by passing in a value of that type. +// +// The name may be a dot-delimited string (e.g., "Foo.Bar") to ignore a +// specific sub-field that is embedded or nested within the parent struct. +// +// This does not handle unexported fields; use IgnoreUnexported instead. +func IgnoreFields(typ interface{}, names ...string) cmp.Option { + sf := newStructFilter(typ, names...) + return cmp.FilterPath(sf.filter, cmp.Ignore()) +} + +// IgnoreTypes returns an Option that ignores all values assignable to +// certain types, which are specified by passing in a value of each type. +func IgnoreTypes(typs ...interface{}) cmp.Option { + tf := newTypeFilter(typs...) + return cmp.FilterPath(tf.filter, cmp.Ignore()) +} + +type typeFilter []reflect.Type + +func newTypeFilter(typs ...interface{}) (tf typeFilter) { + for _, typ := range typs { + t := reflect.TypeOf(typ) + if t == nil { + // This occurs if someone tries to pass in sync.Locker(nil) + panic("cannot determine type; consider using IgnoreInterfaces") + } + tf = append(tf, t) + } + return tf +} +func (tf typeFilter) filter(p cmp.Path) bool { + if len(p) < 1 { + return false + } + t := p.Last().Type() + for _, ti := range tf { + if t.AssignableTo(ti) { + return true + } + } + return false +} + +// IgnoreInterfaces returns an Option that ignores all values or references of +// values assignable to certain interface types. These interfaces are specified +// by passing in an anonymous struct with the interface types embedded in it. +// For example, to ignore sync.Locker, pass in struct{sync.Locker}{}. +func IgnoreInterfaces(ifaces interface{}) cmp.Option { + tf := newIfaceFilter(ifaces) + return cmp.FilterPath(tf.filter, cmp.Ignore()) +} + +type ifaceFilter []reflect.Type + +func newIfaceFilter(ifaces interface{}) (tf ifaceFilter) { + t := reflect.TypeOf(ifaces) + if ifaces == nil || t.Name() != "" || t.Kind() != reflect.Struct { + panic("input must be an anonymous struct") + } + for i := 0; i < t.NumField(); i++ { + fi := t.Field(i) + switch { + case !fi.Anonymous: + panic("struct cannot have named fields") + case fi.Type.Kind() != reflect.Interface: + panic("embedded field must be an interface type") + case fi.Type.NumMethod() == 0: + // This matches everything; why would you ever want this? + panic("cannot ignore empty interface") + default: + tf = append(tf, fi.Type) + } + } + return tf +} +func (tf ifaceFilter) filter(p cmp.Path) bool { + if len(p) < 1 { + return false + } + t := p.Last().Type() + for _, ti := range tf { + if t.AssignableTo(ti) { + return true + } + if t.Kind() != reflect.Ptr && reflect.PtrTo(t).AssignableTo(ti) { + return true + } + } + return false +} + +// IgnoreUnexported returns an Option that only ignores the immediate unexported +// fields of a struct, including anonymous fields of unexported types. +// In particular, unexported fields within the struct's exported fields +// of struct types, including anonymous fields, will not be ignored unless the +// type of the field itself is also passed to IgnoreUnexported. +func IgnoreUnexported(typs ...interface{}) cmp.Option { + ux := newUnexportedFilter(typs...) + return cmp.FilterPath(ux.filter, cmp.Ignore()) +} + +type unexportedFilter struct{ m map[reflect.Type]bool } + +func newUnexportedFilter(typs ...interface{}) unexportedFilter { + ux := unexportedFilter{m: make(map[reflect.Type]bool)} + for _, typ := range typs { + t := reflect.TypeOf(typ) + if t == nil || t.Kind() != reflect.Struct { + panic(fmt.Sprintf("invalid struct type: %T", typ)) + } + ux.m[t] = true + } + return ux +} +func (xf unexportedFilter) filter(p cmp.Path) bool { + sf, ok := p.Index(-1).(cmp.StructField) + if !ok { + return false + } + return xf.m[p.Index(-2).Type()] && !isExported(sf.Name()) +} + +// isExported reports whether the identifier is exported. +func isExported(id string) bool { + r, _ := utf8.DecodeRuneInString(id) + return unicode.IsUpper(r) +} diff --git a/vendor/github.com/google/go-cmp/cmp/cmpopts/sort.go b/vendor/github.com/google/go-cmp/cmp/cmpopts/sort.go new file mode 100644 index 000000000..da17d7469 --- /dev/null +++ b/vendor/github.com/google/go-cmp/cmp/cmpopts/sort.go @@ -0,0 +1,146 @@ +// Copyright 2017, The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE.md file. + +package cmpopts + +import ( + "fmt" + "reflect" + + "github.com/google/go-cmp/cmp" + "github.com/google/go-cmp/cmp/internal/function" +) + +// SortSlices returns a Transformer option that sorts all []V. +// The less function must be of the form "func(T, T) bool" which is used to +// sort any slice with element type V that is assignable to T. +// +// The less function must be: +// • Deterministic: less(x, y) == less(x, y) +// • Irreflexive: !less(x, x) +// • Transitive: if !less(x, y) and !less(y, z), then !less(x, z) +// +// The less function does not have to be "total". That is, if !less(x, y) and +// !less(y, x) for two elements x and y, their relative order is maintained. +// +// SortSlices can be used in conjunction with EquateEmpty. +func SortSlices(less interface{}) cmp.Option { + vf := reflect.ValueOf(less) + if !function.IsType(vf.Type(), function.Less) || vf.IsNil() { + panic(fmt.Sprintf("invalid less function: %T", less)) + } + ss := sliceSorter{vf.Type().In(0), vf} + return cmp.FilterValues(ss.filter, cmp.Transformer("Sort", ss.sort)) +} + +type sliceSorter struct { + in reflect.Type // T + fnc reflect.Value // func(T, T) bool +} + +func (ss sliceSorter) filter(x, y interface{}) bool { + vx, vy := reflect.ValueOf(x), reflect.ValueOf(y) + if !(x != nil && y != nil && vx.Type() == vy.Type()) || + !(vx.Kind() == reflect.Slice && vx.Type().Elem().AssignableTo(ss.in)) || + (vx.Len() <= 1 && vy.Len() <= 1) { + return false + } + // Check whether the slices are already sorted to avoid an infinite + // recursion cycle applying the same transform to itself. + ok1 := sliceIsSorted(x, func(i, j int) bool { return ss.less(vx, i, j) }) + ok2 := sliceIsSorted(y, func(i, j int) bool { return ss.less(vy, i, j) }) + return !ok1 || !ok2 +} +func (ss sliceSorter) sort(x interface{}) interface{} { + src := reflect.ValueOf(x) + dst := reflect.MakeSlice(src.Type(), src.Len(), src.Len()) + for i := 0; i < src.Len(); i++ { + dst.Index(i).Set(src.Index(i)) + } + sortSliceStable(dst.Interface(), func(i, j int) bool { return ss.less(dst, i, j) }) + ss.checkSort(dst) + return dst.Interface() +} +func (ss sliceSorter) checkSort(v reflect.Value) { + start := -1 // Start of a sequence of equal elements. + for i := 1; i < v.Len(); i++ { + if ss.less(v, i-1, i) { + // Check that first and last elements in v[start:i] are equal. + if start >= 0 && (ss.less(v, start, i-1) || ss.less(v, i-1, start)) { + panic(fmt.Sprintf("incomparable values detected: want equal elements: %v", v.Slice(start, i))) + } + start = -1 + } else if start == -1 { + start = i + } + } +} +func (ss sliceSorter) less(v reflect.Value, i, j int) bool { + vx, vy := v.Index(i), v.Index(j) + return ss.fnc.Call([]reflect.Value{vx, vy})[0].Bool() +} + +// SortMaps returns a Transformer option that flattens map[K]V types to be a +// sorted []struct{K, V}. The less function must be of the form +// "func(T, T) bool" which is used to sort any map with key K that is +// assignable to T. +// +// Flattening the map into a slice has the property that cmp.Equal is able to +// use Comparers on K or the K.Equal method if it exists. +// +// The less function must be: +// • Deterministic: less(x, y) == less(x, y) +// • Irreflexive: !less(x, x) +// • Transitive: if !less(x, y) and !less(y, z), then !less(x, z) +// • Total: if x != y, then either less(x, y) or less(y, x) +// +// SortMaps can be used in conjunction with EquateEmpty. +func SortMaps(less interface{}) cmp.Option { + vf := reflect.ValueOf(less) + if !function.IsType(vf.Type(), function.Less) || vf.IsNil() { + panic(fmt.Sprintf("invalid less function: %T", less)) + } + ms := mapSorter{vf.Type().In(0), vf} + return cmp.FilterValues(ms.filter, cmp.Transformer("Sort", ms.sort)) +} + +type mapSorter struct { + in reflect.Type // T + fnc reflect.Value // func(T, T) bool +} + +func (ms mapSorter) filter(x, y interface{}) bool { + vx, vy := reflect.ValueOf(x), reflect.ValueOf(y) + return (x != nil && y != nil && vx.Type() == vy.Type()) && + (vx.Kind() == reflect.Map && vx.Type().Key().AssignableTo(ms.in)) && + (vx.Len() != 0 || vy.Len() != 0) +} +func (ms mapSorter) sort(x interface{}) interface{} { + src := reflect.ValueOf(x) + outType := mapEntryType(src.Type()) + dst := reflect.MakeSlice(reflect.SliceOf(outType), src.Len(), src.Len()) + for i, k := range src.MapKeys() { + v := reflect.New(outType).Elem() + v.Field(0).Set(k) + v.Field(1).Set(src.MapIndex(k)) + dst.Index(i).Set(v) + } + sortSlice(dst.Interface(), func(i, j int) bool { return ms.less(dst, i, j) }) + ms.checkSort(dst) + return dst.Interface() +} +func (ms mapSorter) checkSort(v reflect.Value) { + for i := 1; i < v.Len(); i++ { + if !ms.less(v, i-1, i) { + panic(fmt.Sprintf("partial order detected: want %v < %v", v.Index(i-1), v.Index(i))) + } + } +} +func (ms mapSorter) less(v reflect.Value, i, j int) bool { + vx, vy := v.Index(i).Field(0), v.Index(j).Field(0) + if !hasReflectStructOf { + vx, vy = vx.Elem(), vy.Elem() + } + return ms.fnc.Call([]reflect.Value{vx, vy})[0].Bool() +} diff --git a/vendor/github.com/google/go-cmp/cmp/cmpopts/sort_go17.go b/vendor/github.com/google/go-cmp/cmp/cmpopts/sort_go17.go new file mode 100644 index 000000000..839b88ca4 --- /dev/null +++ b/vendor/github.com/google/go-cmp/cmp/cmpopts/sort_go17.go @@ -0,0 +1,46 @@ +// Copyright 2017, The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE.md file. + +// +build !go1.8 + +package cmpopts + +import ( + "reflect" + "sort" +) + +const hasReflectStructOf = false + +func mapEntryType(reflect.Type) reflect.Type { + return reflect.TypeOf(struct{ K, V interface{} }{}) +} + +func sliceIsSorted(slice interface{}, less func(i, j int) bool) bool { + return sort.IsSorted(reflectSliceSorter{reflect.ValueOf(slice), less}) +} +func sortSlice(slice interface{}, less func(i, j int) bool) { + sort.Sort(reflectSliceSorter{reflect.ValueOf(slice), less}) +} +func sortSliceStable(slice interface{}, less func(i, j int) bool) { + sort.Stable(reflectSliceSorter{reflect.ValueOf(slice), less}) +} + +type reflectSliceSorter struct { + slice reflect.Value + less func(i, j int) bool +} + +func (ss reflectSliceSorter) Len() int { + return ss.slice.Len() +} +func (ss reflectSliceSorter) Less(i, j int) bool { + return ss.less(i, j) +} +func (ss reflectSliceSorter) Swap(i, j int) { + vi := ss.slice.Index(i).Interface() + vj := ss.slice.Index(j).Interface() + ss.slice.Index(i).Set(reflect.ValueOf(vj)) + ss.slice.Index(j).Set(reflect.ValueOf(vi)) +} diff --git a/vendor/github.com/google/go-cmp/cmp/cmpopts/sort_go18.go b/vendor/github.com/google/go-cmp/cmp/cmpopts/sort_go18.go new file mode 100644 index 000000000..8a59c0d38 --- /dev/null +++ b/vendor/github.com/google/go-cmp/cmp/cmpopts/sort_go18.go @@ -0,0 +1,31 @@ +// Copyright 2017, The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE.md file. + +// +build go1.8 + +package cmpopts + +import ( + "reflect" + "sort" +) + +const hasReflectStructOf = true + +func mapEntryType(t reflect.Type) reflect.Type { + return reflect.StructOf([]reflect.StructField{ + {Name: "K", Type: t.Key()}, + {Name: "V", Type: t.Elem()}, + }) +} + +func sliceIsSorted(slice interface{}, less func(i, j int) bool) bool { + return sort.SliceIsSorted(slice, less) +} +func sortSlice(slice interface{}, less func(i, j int) bool) { + sort.Slice(slice, less) +} +func sortSliceStable(slice interface{}, less func(i, j int) bool) { + sort.SliceStable(slice, less) +} diff --git a/vendor/github.com/google/go-cmp/cmp/cmpopts/struct_filter.go b/vendor/github.com/google/go-cmp/cmp/cmpopts/struct_filter.go new file mode 100644 index 000000000..97f707983 --- /dev/null +++ b/vendor/github.com/google/go-cmp/cmp/cmpopts/struct_filter.go @@ -0,0 +1,182 @@ +// Copyright 2017, The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE.md file. + +package cmpopts + +import ( + "fmt" + "reflect" + "strings" + + "github.com/google/go-cmp/cmp" +) + +// filterField returns a new Option where opt is only evaluated on paths that +// include a specific exported field on a single struct type. +// The struct type is specified by passing in a value of that type. +// +// The name may be a dot-delimited string (e.g., "Foo.Bar") to select a +// specific sub-field that is embedded or nested within the parent struct. +func filterField(typ interface{}, name string, opt cmp.Option) cmp.Option { + // TODO: This is currently unexported over concerns of how helper filters + // can be composed together easily. + // TODO: Add tests for FilterField. + + sf := newStructFilter(typ, name) + return cmp.FilterPath(sf.filter, opt) +} + +type structFilter struct { + t reflect.Type // The root struct type to match on + ft fieldTree // Tree of fields to match on +} + +func newStructFilter(typ interface{}, names ...string) structFilter { + // TODO: Perhaps allow * as a special identifier to allow ignoring any + // number of path steps until the next field match? + // This could be useful when a concrete struct gets transformed into + // an anonymous struct where it is not possible to specify that by type, + // but the transformer happens to provide guarantees about the names of + // the transformed fields. + + t := reflect.TypeOf(typ) + if t == nil || t.Kind() != reflect.Struct { + panic(fmt.Sprintf("%T must be a struct", typ)) + } + var ft fieldTree + for _, name := range names { + cname, err := canonicalName(t, name) + if err != nil { + panic(fmt.Sprintf("%s: %v", strings.Join(cname, "."), err)) + } + ft.insert(cname) + } + return structFilter{t, ft} +} + +func (sf structFilter) filter(p cmp.Path) bool { + for i, ps := range p { + if ps.Type().AssignableTo(sf.t) && sf.ft.matchPrefix(p[i+1:]) { + return true + } + } + return false +} + +// fieldTree represents a set of dot-separated identifiers. +// +// For example, inserting the following selectors: +// Foo +// Foo.Bar.Baz +// Foo.Buzz +// Nuka.Cola.Quantum +// +// Results in a tree of the form: +// {sub: { +// "Foo": {ok: true, sub: { +// "Bar": {sub: { +// "Baz": {ok: true}, +// }}, +// "Buzz": {ok: true}, +// }}, +// "Nuka": {sub: { +// "Cola": {sub: { +// "Quantum": {ok: true}, +// }}, +// }}, +// }} +type fieldTree struct { + ok bool // Whether this is a specified node + sub map[string]fieldTree // The sub-tree of fields under this node +} + +// insert inserts a sequence of field accesses into the tree. +func (ft *fieldTree) insert(cname []string) { + if ft.sub == nil { + ft.sub = make(map[string]fieldTree) + } + if len(cname) == 0 { + ft.ok = true + return + } + sub := ft.sub[cname[0]] + sub.insert(cname[1:]) + ft.sub[cname[0]] = sub +} + +// matchPrefix reports whether any selector in the fieldTree matches +// the start of path p. +func (ft fieldTree) matchPrefix(p cmp.Path) bool { + for _, ps := range p { + switch ps := ps.(type) { + case cmp.StructField: + ft = ft.sub[ps.Name()] + if ft.ok { + return true + } + if len(ft.sub) == 0 { + return false + } + case cmp.Indirect: + default: + return false + } + } + return false +} + +// canonicalName returns a list of identifiers where any struct field access +// through an embedded field is expanded to include the names of the embedded +// types themselves. +// +// For example, suppose field "Foo" is not directly in the parent struct, +// but actually from an embedded struct of type "Bar". Then, the canonical name +// of "Foo" is actually "Bar.Foo". +// +// Suppose field "Foo" is not directly in the parent struct, but actually +// a field in two different embedded structs of types "Bar" and "Baz". +// Then the selector "Foo" causes a panic since it is ambiguous which one it +// refers to. The user must specify either "Bar.Foo" or "Baz.Foo". +func canonicalName(t reflect.Type, sel string) ([]string, error) { + var name string + sel = strings.TrimPrefix(sel, ".") + if sel == "" { + return nil, fmt.Errorf("name must not be empty") + } + if i := strings.IndexByte(sel, '.'); i < 0 { + name, sel = sel, "" + } else { + name, sel = sel[:i], sel[i:] + } + + // Type must be a struct or pointer to struct. + if t.Kind() == reflect.Ptr { + t = t.Elem() + } + if t.Kind() != reflect.Struct { + return nil, fmt.Errorf("%v must be a struct", t) + } + + // Find the canonical name for this current field name. + // If the field exists in an embedded struct, then it will be expanded. + if !isExported(name) { + // Disallow unexported fields: + // * To discourage people from actually touching unexported fields + // * FieldByName is buggy (https://golang.org/issue/4876) + return []string{name}, fmt.Errorf("name must be exported") + } + sf, ok := t.FieldByName(name) + if !ok { + return []string{name}, fmt.Errorf("does not exist") + } + var ss []string + for i := range sf.Index { + ss = append(ss, t.FieldByIndex(sf.Index[:i+1]).Name) + } + if sel == "" { + return ss, nil + } + ssPost, err := canonicalName(sf.Type, sel) + return append(ss, ssPost...), err +}