diff --git a/cmp/compare.go b/cmp/compare.go index 2133562..8419fcc 100644 --- a/cmp/compare.go +++ b/cmp/compare.go @@ -22,8 +22,8 @@ // equality is determined by recursively comparing the primitive kinds on both // values, much like reflect.DeepEqual. Unlike reflect.DeepEqual, unexported // fields are not compared by default; they result in panics unless suppressed -// by using an Ignore option (see cmpopts.IgnoreUnexported) or explicitly compared -// using the AllowUnexported option. +// by using an Ignore option (see cmpopts.IgnoreUnexported) or explicitly +// compared using the Exporter option. package cmp import ( @@ -62,8 +62,8 @@ import ( // // Structs are equal if recursively calling Equal on all fields report equal. // If a struct contains unexported fields, Equal panics unless an Ignore option -// (e.g., cmpopts.IgnoreUnexported) ignores that field or the AllowUnexported -// option explicitly permits comparing the unexported field. +// (e.g., cmpopts.IgnoreUnexported) ignores that field or the Exporter option +// explicitly permits comparing the unexported field. // // Slices are equal if they are both nil or both non-nil, where recursively // calling Equal on all non-ignored slice or array elements report equal. @@ -148,8 +148,8 @@ type state struct { dynChecker dynChecker // These fields, once set by processOption, will not change. - exporters map[reflect.Type]bool // Set of structs with unexported field visibility - opts Options // List of all fundamental and filter options + exporters []exporter // List of exporters for structs with unexported fields + opts Options // List of all fundamental and filter options } func newState(opts []Option) *state { @@ -174,13 +174,8 @@ func (s *state) processOption(opt Option) { panic(fmt.Sprintf("cannot use an unfiltered option: %v", opt)) } s.opts = append(s.opts, opt) - case visibleStructs: - if s.exporters == nil { - s.exporters = make(map[reflect.Type]bool) - } - for t := range opt { - s.exporters[t] = true - } + case exporter: + s.exporters = append(s.exporters, opt) case reporter: s.reporters = append(s.reporters, opt) default: @@ -354,6 +349,7 @@ func sanitizeValue(v reflect.Value, t reflect.Type) reflect.Value { func (s *state) compareStruct(t reflect.Type, vx, vy reflect.Value) { var vax, vay reflect.Value // Addressable versions of vx and vy + var mayForce, mayForceInit bool step := StructField{&structField{}} for i := 0; i < t.NumField(); i++ { step.typ = t.Field(i).Type @@ -375,7 +371,13 @@ func (s *state) compareStruct(t reflect.Type, vx, vy reflect.Value) { vax = makeAddressable(vx) vay = makeAddressable(vy) } - step.mayForce = s.exporters[t] + if !mayForceInit { + for _, xf := range s.exporters { + mayForce = mayForce || xf(t) + } + mayForceInit = true + } + step.mayForce = mayForce step.pvx = vax step.pvy = vay step.field = t.Field(i) diff --git a/cmp/export_panic.go b/cmp/export_panic.go index abc3a1c..dd03235 100644 --- a/cmp/export_panic.go +++ b/cmp/export_panic.go @@ -8,8 +8,8 @@ package cmp import "reflect" -const supportAllowUnexported = false +const supportExporters = false func retrieveUnexportedField(reflect.Value, reflect.StructField) reflect.Value { - panic("retrieveUnexportedField is not implemented") + panic("no support for forcibly accessing unexported fields") } diff --git a/cmp/export_unsafe.go b/cmp/export_unsafe.go index 5f6ed93..57020e2 100644 --- a/cmp/export_unsafe.go +++ b/cmp/export_unsafe.go @@ -11,7 +11,7 @@ import ( "unsafe" ) -const supportAllowUnexported = true +const supportExporters = true // retrieveUnexportedField uses unsafe to forcibly retrieve any field from // a struct such that the value has read-write permissions. diff --git a/cmp/options.go b/cmp/options.go index a20390d..409e803 100644 --- a/cmp/options.go +++ b/cmp/options.go @@ -225,7 +225,7 @@ func (validator) apply(s *state, vx, vy reflect.Value) { // Unable to Interface implies unexported field without visibility access. if !vx.CanInterface() || !vy.CanInterface() { - const help = "consider using a custom Comparer; if you control the implementation of type, you can also consider AllowUnexported or cmpopts.IgnoreUnexported" + const help = "consider using a custom Comparer; if you control the implementation of type, you can also consider using an Exporter, AllowUnexported, or cmpopts.IgnoreUnexported" var name string if t := s.curPath.Index(-2).Type(); t.Name() != "" { // Named type with unexported fields. @@ -372,9 +372,8 @@ func (cm comparer) String() string { return fmt.Sprintf("Comparer(%s)", function.NameOf(cm.fnc)) } -// AllowUnexported returns an Option that forcibly allows operations on -// unexported fields in certain structs, which are specified by passing in a -// value of each struct type. +// Exporter returns an Option that specifies whether Equal is allowed to +// introspect into the unexported fields of certain struct types. // // Users of this option must understand that comparing on unexported fields // from external packages is not safe since changes in the internal @@ -398,10 +397,24 @@ func (cm comparer) String() string { // // In other cases, the cmpopts.IgnoreUnexported option can be used to ignore // all unexported fields on specified struct types. -func AllowUnexported(types ...interface{}) Option { - if !supportAllowUnexported { - panic("AllowUnexported is not supported on purego builds, Google App Engine Standard, or GopherJS") +func Exporter(f func(reflect.Type) bool) Option { + if !supportExporters { + panic("Exporter is not supported on purego builds") } + return exporter(f) +} + +type exporter func(reflect.Type) bool + +func (exporter) filter(_ *state, _ reflect.Type, _, _ reflect.Value) applicableOption { + panic("not implemented") +} + +// AllowUnexported returns an Options that allows Equal to forcibly introspect +// unexported fields of the specified struct types. +// +// See Exporter for the proper use of this option. +func AllowUnexported(types ...interface{}) Option { m := make(map[reflect.Type]bool) for _, typ := range types { t := reflect.TypeOf(typ) @@ -410,13 +423,7 @@ func AllowUnexported(types ...interface{}) Option { } m[t] = true } - return visibleStructs(m) -} - -type visibleStructs map[reflect.Type]bool - -func (visibleStructs) filter(_ *state, _ reflect.Type, _, _ reflect.Value) applicableOption { - panic("not implemented") + return exporter(func(t reflect.Type) bool { return m[t] }) } // Result represents the comparison result for a single node and diff --git a/cmp/path.go b/cmp/path.go index 96fffd2..d7a420d 100644 --- a/cmp/path.go +++ b/cmp/path.go @@ -41,7 +41,7 @@ type PathStep interface { // In some cases, one or both may be invalid or have restrictions: // • For StructField, both are not interface-able if the current field // is unexported and the struct type is not explicitly permitted by - // AllowUnexported to traverse unexported fields. + // an Exporter to traverse unexported fields. // • For SliceIndex, one may be invalid if an element is missing from // either the x or y slice. // • For MapIndex, one may be invalid if an entry is missing from