mirror of
https://github.com/octoleo/restic.git
synced 2024-12-12 06:07:55 +00:00
bff635bc5f
So, `dep` got an nice new feature to remove tests and non-go files from `vendor/`, and this brings the size of the vendor directory from ~300MiB down to ~20MiB. We don that now.
554 lines
18 KiB
Go
554 lines
18 KiB
Go
// 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 cmp determines equality of values.
|
|
//
|
|
// This package is intended to be a more powerful and safer alternative to
|
|
// reflect.DeepEqual for comparing whether two values are semantically equal.
|
|
//
|
|
// The primary features of cmp are:
|
|
//
|
|
// • When the default behavior of equality does not suit the needs of the test,
|
|
// custom equality functions can override the equality operation.
|
|
// For example, an equality function may report floats as equal so long as they
|
|
// are within some tolerance of each other.
|
|
//
|
|
// • Types that have an Equal method may use that method to determine equality.
|
|
// This allows package authors to determine the equality operation for the types
|
|
// that they define.
|
|
//
|
|
// • If no custom equality functions are used and no Equal method is defined,
|
|
// 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.
|
|
package cmp
|
|
|
|
import (
|
|
"fmt"
|
|
"reflect"
|
|
|
|
"github.com/google/go-cmp/cmp/internal/diff"
|
|
"github.com/google/go-cmp/cmp/internal/function"
|
|
"github.com/google/go-cmp/cmp/internal/value"
|
|
)
|
|
|
|
// BUG(dsnet): Maps with keys containing NaN values cannot be properly compared due to
|
|
// the reflection package's inability to retrieve such entries. Equal will panic
|
|
// anytime it comes across a NaN key, but this behavior may change.
|
|
//
|
|
// See https://golang.org/issue/11104 for more details.
|
|
|
|
var nothing = reflect.Value{}
|
|
|
|
// Equal reports whether x and y are equal by recursively applying the
|
|
// following rules in the given order to x and y and all of their sub-values:
|
|
//
|
|
// • If two values are not of the same type, then they are never equal
|
|
// and the overall result is false.
|
|
//
|
|
// • Let S be the set of all Ignore, Transformer, and Comparer options that
|
|
// remain after applying all path filters, value filters, and type filters.
|
|
// If at least one Ignore exists in S, then the comparison is ignored.
|
|
// If the number of Transformer and Comparer options in S is greater than one,
|
|
// then Equal panics because it is ambiguous which option to use.
|
|
// If S contains a single Transformer, then use that to transform the current
|
|
// values and recursively call Equal on the output values.
|
|
// If S contains a single Comparer, then use that to compare the current values.
|
|
// Otherwise, evaluation proceeds to the next rule.
|
|
//
|
|
// • If the values have an Equal method of the form "(T) Equal(T) bool" or
|
|
// "(T) Equal(I) bool" where T is assignable to I, then use the result of
|
|
// x.Equal(y) even if x or y is nil.
|
|
// Otherwise, no such method exists and evaluation proceeds to the next rule.
|
|
//
|
|
// • Lastly, try to compare x and y based on their basic kinds.
|
|
// Simple kinds like booleans, integers, floats, complex numbers, strings, and
|
|
// channels are compared using the equivalent of the == operator in Go.
|
|
// Functions are only equal if they are both nil, otherwise they are unequal.
|
|
// Pointers are equal if the underlying values they point to are also equal.
|
|
// Interfaces are equal if their underlying concrete values are also equal.
|
|
//
|
|
// Structs are equal if all of their fields are equal. If a struct contains
|
|
// unexported fields, Equal panics unless the AllowUnexported option is used or
|
|
// an Ignore option (e.g., cmpopts.IgnoreUnexported) ignores that field.
|
|
//
|
|
// Arrays, slices, and maps are equal if they are both nil or both non-nil
|
|
// with the same length and the elements at each index or key are equal.
|
|
// Note that a non-nil empty slice and a nil slice are not equal.
|
|
// To equate empty slices and maps, consider using cmpopts.EquateEmpty.
|
|
// Map keys are equal according to the == operator.
|
|
// To use custom comparisons for map keys, consider using cmpopts.SortMaps.
|
|
func Equal(x, y interface{}, opts ...Option) bool {
|
|
s := newState(opts)
|
|
s.compareAny(reflect.ValueOf(x), reflect.ValueOf(y))
|
|
return s.result.Equal()
|
|
}
|
|
|
|
// Diff returns a human-readable report of the differences between two values.
|
|
// It returns an empty string if and only if Equal returns true for the same
|
|
// input values and options. The output string will use the "-" symbol to
|
|
// indicate elements removed from x, and the "+" symbol to indicate elements
|
|
// added to y.
|
|
//
|
|
// Do not depend on this output being stable.
|
|
func Diff(x, y interface{}, opts ...Option) string {
|
|
r := new(defaultReporter)
|
|
opts = Options{Options(opts), r}
|
|
eq := Equal(x, y, opts...)
|
|
d := r.String()
|
|
if (d == "") != eq {
|
|
panic("inconsistent difference and equality results")
|
|
}
|
|
return d
|
|
}
|
|
|
|
type state struct {
|
|
// These fields represent the "comparison state".
|
|
// Calling statelessCompare must not result in observable changes to these.
|
|
result diff.Result // The current result of comparison
|
|
curPath Path // The current path in the value tree
|
|
reporter reporter // Optional reporter used for difference formatting
|
|
|
|
// dynChecker triggers pseudo-random checks for option correctness.
|
|
// It is safe for statelessCompare to mutate this value.
|
|
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
|
|
}
|
|
|
|
func newState(opts []Option) *state {
|
|
s := new(state)
|
|
for _, opt := range opts {
|
|
s.processOption(opt)
|
|
}
|
|
return s
|
|
}
|
|
|
|
func (s *state) processOption(opt Option) {
|
|
switch opt := opt.(type) {
|
|
case nil:
|
|
case Options:
|
|
for _, o := range opt {
|
|
s.processOption(o)
|
|
}
|
|
case coreOption:
|
|
type filtered interface {
|
|
isFiltered() bool
|
|
}
|
|
if fopt, ok := opt.(filtered); ok && !fopt.isFiltered() {
|
|
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 reporter:
|
|
if s.reporter != nil {
|
|
panic("difference reporter already registered")
|
|
}
|
|
s.reporter = opt
|
|
default:
|
|
panic(fmt.Sprintf("unknown option %T", opt))
|
|
}
|
|
}
|
|
|
|
// statelessCompare compares two values and returns the result.
|
|
// This function is stateless in that it does not alter the current result,
|
|
// or output to any registered reporters.
|
|
func (s *state) statelessCompare(vx, vy reflect.Value) diff.Result {
|
|
// We do not save and restore the curPath because all of the compareX
|
|
// methods should properly push and pop from the path.
|
|
// It is an implementation bug if the contents of curPath differs from
|
|
// when calling this function to when returning from it.
|
|
|
|
oldResult, oldReporter := s.result, s.reporter
|
|
s.result = diff.Result{} // Reset result
|
|
s.reporter = nil // Remove reporter to avoid spurious printouts
|
|
s.compareAny(vx, vy)
|
|
res := s.result
|
|
s.result, s.reporter = oldResult, oldReporter
|
|
return res
|
|
}
|
|
|
|
func (s *state) compareAny(vx, vy reflect.Value) {
|
|
// TODO: Support cyclic data structures.
|
|
|
|
// Rule 0: Differing types are never equal.
|
|
if !vx.IsValid() || !vy.IsValid() {
|
|
s.report(vx.IsValid() == vy.IsValid(), vx, vy)
|
|
return
|
|
}
|
|
if vx.Type() != vy.Type() {
|
|
s.report(false, vx, vy) // Possible for path to be empty
|
|
return
|
|
}
|
|
t := vx.Type()
|
|
if len(s.curPath) == 0 {
|
|
s.curPath.push(&pathStep{typ: t})
|
|
defer s.curPath.pop()
|
|
}
|
|
vx, vy = s.tryExporting(vx, vy)
|
|
|
|
// Rule 1: Check whether an option applies on this node in the value tree.
|
|
if s.tryOptions(vx, vy, t) {
|
|
return
|
|
}
|
|
|
|
// Rule 2: Check whether the type has a valid Equal method.
|
|
if s.tryMethod(vx, vy, t) {
|
|
return
|
|
}
|
|
|
|
// Rule 3: Recursively descend into each value's underlying kind.
|
|
switch t.Kind() {
|
|
case reflect.Bool:
|
|
s.report(vx.Bool() == vy.Bool(), vx, vy)
|
|
return
|
|
case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
|
|
s.report(vx.Int() == vy.Int(), vx, vy)
|
|
return
|
|
case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
|
|
s.report(vx.Uint() == vy.Uint(), vx, vy)
|
|
return
|
|
case reflect.Float32, reflect.Float64:
|
|
s.report(vx.Float() == vy.Float(), vx, vy)
|
|
return
|
|
case reflect.Complex64, reflect.Complex128:
|
|
s.report(vx.Complex() == vy.Complex(), vx, vy)
|
|
return
|
|
case reflect.String:
|
|
s.report(vx.String() == vy.String(), vx, vy)
|
|
return
|
|
case reflect.Chan, reflect.UnsafePointer:
|
|
s.report(vx.Pointer() == vy.Pointer(), vx, vy)
|
|
return
|
|
case reflect.Func:
|
|
s.report(vx.IsNil() && vy.IsNil(), vx, vy)
|
|
return
|
|
case reflect.Ptr:
|
|
if vx.IsNil() || vy.IsNil() {
|
|
s.report(vx.IsNil() && vy.IsNil(), vx, vy)
|
|
return
|
|
}
|
|
s.curPath.push(&indirect{pathStep{t.Elem()}})
|
|
defer s.curPath.pop()
|
|
s.compareAny(vx.Elem(), vy.Elem())
|
|
return
|
|
case reflect.Interface:
|
|
if vx.IsNil() || vy.IsNil() {
|
|
s.report(vx.IsNil() && vy.IsNil(), vx, vy)
|
|
return
|
|
}
|
|
if vx.Elem().Type() != vy.Elem().Type() {
|
|
s.report(false, vx.Elem(), vy.Elem())
|
|
return
|
|
}
|
|
s.curPath.push(&typeAssertion{pathStep{vx.Elem().Type()}})
|
|
defer s.curPath.pop()
|
|
s.compareAny(vx.Elem(), vy.Elem())
|
|
return
|
|
case reflect.Slice:
|
|
if vx.IsNil() || vy.IsNil() {
|
|
s.report(vx.IsNil() && vy.IsNil(), vx, vy)
|
|
return
|
|
}
|
|
fallthrough
|
|
case reflect.Array:
|
|
s.compareArray(vx, vy, t)
|
|
return
|
|
case reflect.Map:
|
|
s.compareMap(vx, vy, t)
|
|
return
|
|
case reflect.Struct:
|
|
s.compareStruct(vx, vy, t)
|
|
return
|
|
default:
|
|
panic(fmt.Sprintf("%v kind not handled", t.Kind()))
|
|
}
|
|
}
|
|
|
|
func (s *state) tryExporting(vx, vy reflect.Value) (reflect.Value, reflect.Value) {
|
|
if sf, ok := s.curPath[len(s.curPath)-1].(*structField); ok && sf.unexported {
|
|
if sf.force {
|
|
// Use unsafe pointer arithmetic to get read-write access to an
|
|
// unexported field in the struct.
|
|
vx = unsafeRetrieveField(sf.pvx, sf.field)
|
|
vy = unsafeRetrieveField(sf.pvy, sf.field)
|
|
} else {
|
|
// We are not allowed to export the value, so invalidate them
|
|
// so that tryOptions can panic later if not explicitly ignored.
|
|
vx = nothing
|
|
vy = nothing
|
|
}
|
|
}
|
|
return vx, vy
|
|
}
|
|
|
|
func (s *state) tryOptions(vx, vy reflect.Value, t reflect.Type) bool {
|
|
// If there were no FilterValues, we will not detect invalid inputs,
|
|
// so manually check for them and append invalid if necessary.
|
|
// We still evaluate the options since an ignore can override invalid.
|
|
opts := s.opts
|
|
if !vx.IsValid() || !vy.IsValid() {
|
|
opts = Options{opts, invalid{}}
|
|
}
|
|
|
|
// Evaluate all filters and apply the remaining options.
|
|
if opt := opts.filter(s, vx, vy, t); opt != nil {
|
|
opt.apply(s, vx, vy)
|
|
return true
|
|
}
|
|
return false
|
|
}
|
|
|
|
func (s *state) tryMethod(vx, vy reflect.Value, t reflect.Type) bool {
|
|
// Check if this type even has an Equal method.
|
|
m, ok := t.MethodByName("Equal")
|
|
if !ok || !function.IsType(m.Type, function.EqualAssignable) {
|
|
return false
|
|
}
|
|
|
|
eq := s.callTTBFunc(m.Func, vx, vy)
|
|
s.report(eq, vx, vy)
|
|
return true
|
|
}
|
|
|
|
func (s *state) callTRFunc(f, v reflect.Value) reflect.Value {
|
|
v = sanitizeValue(v, f.Type().In(0))
|
|
if !s.dynChecker.Next() {
|
|
return f.Call([]reflect.Value{v})[0]
|
|
}
|
|
|
|
// Run the function twice and ensure that we get the same results back.
|
|
// We run in goroutines so that the race detector (if enabled) can detect
|
|
// unsafe mutations to the input.
|
|
c := make(chan reflect.Value)
|
|
go detectRaces(c, f, v)
|
|
want := f.Call([]reflect.Value{v})[0]
|
|
if got := <-c; !s.statelessCompare(got, want).Equal() {
|
|
// To avoid false-positives with non-reflexive equality operations,
|
|
// we sanity check whether a value is equal to itself.
|
|
if !s.statelessCompare(want, want).Equal() {
|
|
return want
|
|
}
|
|
fn := getFuncName(f.Pointer())
|
|
panic(fmt.Sprintf("non-deterministic function detected: %s", fn))
|
|
}
|
|
return want
|
|
}
|
|
|
|
func (s *state) callTTBFunc(f, x, y reflect.Value) bool {
|
|
x = sanitizeValue(x, f.Type().In(0))
|
|
y = sanitizeValue(y, f.Type().In(1))
|
|
if !s.dynChecker.Next() {
|
|
return f.Call([]reflect.Value{x, y})[0].Bool()
|
|
}
|
|
|
|
// Swapping the input arguments is sufficient to check that
|
|
// f is symmetric and deterministic.
|
|
// We run in goroutines so that the race detector (if enabled) can detect
|
|
// unsafe mutations to the input.
|
|
c := make(chan reflect.Value)
|
|
go detectRaces(c, f, y, x)
|
|
want := f.Call([]reflect.Value{x, y})[0].Bool()
|
|
if got := <-c; !got.IsValid() || got.Bool() != want {
|
|
fn := getFuncName(f.Pointer())
|
|
panic(fmt.Sprintf("non-deterministic or non-symmetric function detected: %s", fn))
|
|
}
|
|
return want
|
|
}
|
|
|
|
func detectRaces(c chan<- reflect.Value, f reflect.Value, vs ...reflect.Value) {
|
|
var ret reflect.Value
|
|
defer func() {
|
|
recover() // Ignore panics, let the other call to f panic instead
|
|
c <- ret
|
|
}()
|
|
ret = f.Call(vs)[0]
|
|
}
|
|
|
|
// sanitizeValue converts nil interfaces of type T to those of type R,
|
|
// assuming that T is assignable to R.
|
|
// Otherwise, it returns the input value as is.
|
|
func sanitizeValue(v reflect.Value, t reflect.Type) reflect.Value {
|
|
// TODO(dsnet): Remove this hacky workaround.
|
|
// See https://golang.org/issue/22143
|
|
if v.Kind() == reflect.Interface && v.IsNil() && v.Type() != t {
|
|
return reflect.New(t).Elem()
|
|
}
|
|
return v
|
|
}
|
|
|
|
func (s *state) compareArray(vx, vy reflect.Value, t reflect.Type) {
|
|
step := &sliceIndex{pathStep{t.Elem()}, 0, 0}
|
|
s.curPath.push(step)
|
|
|
|
// Compute an edit-script for slices vx and vy.
|
|
es := diff.Difference(vx.Len(), vy.Len(), func(ix, iy int) diff.Result {
|
|
step.xkey, step.ykey = ix, iy
|
|
return s.statelessCompare(vx.Index(ix), vy.Index(iy))
|
|
})
|
|
|
|
// Report the entire slice as is if the arrays are of primitive kind,
|
|
// and the arrays are different enough.
|
|
isPrimitive := false
|
|
switch t.Elem().Kind() {
|
|
case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64,
|
|
reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr,
|
|
reflect.Bool, reflect.Float32, reflect.Float64, reflect.Complex64, reflect.Complex128:
|
|
isPrimitive = true
|
|
}
|
|
if isPrimitive && es.Dist() > (vx.Len()+vy.Len())/4 {
|
|
s.curPath.pop() // Pop first since we are reporting the whole slice
|
|
s.report(false, vx, vy)
|
|
return
|
|
}
|
|
|
|
// Replay the edit-script.
|
|
var ix, iy int
|
|
for _, e := range es {
|
|
switch e {
|
|
case diff.UniqueX:
|
|
step.xkey, step.ykey = ix, -1
|
|
s.report(false, vx.Index(ix), nothing)
|
|
ix++
|
|
case diff.UniqueY:
|
|
step.xkey, step.ykey = -1, iy
|
|
s.report(false, nothing, vy.Index(iy))
|
|
iy++
|
|
default:
|
|
step.xkey, step.ykey = ix, iy
|
|
if e == diff.Identity {
|
|
s.report(true, vx.Index(ix), vy.Index(iy))
|
|
} else {
|
|
s.compareAny(vx.Index(ix), vy.Index(iy))
|
|
}
|
|
ix++
|
|
iy++
|
|
}
|
|
}
|
|
s.curPath.pop()
|
|
return
|
|
}
|
|
|
|
func (s *state) compareMap(vx, vy reflect.Value, t reflect.Type) {
|
|
if vx.IsNil() || vy.IsNil() {
|
|
s.report(vx.IsNil() && vy.IsNil(), vx, vy)
|
|
return
|
|
}
|
|
|
|
// We combine and sort the two map keys so that we can perform the
|
|
// comparisons in a deterministic order.
|
|
step := &mapIndex{pathStep: pathStep{t.Elem()}}
|
|
s.curPath.push(step)
|
|
defer s.curPath.pop()
|
|
for _, k := range value.SortKeys(append(vx.MapKeys(), vy.MapKeys()...)) {
|
|
step.key = k
|
|
vvx := vx.MapIndex(k)
|
|
vvy := vy.MapIndex(k)
|
|
switch {
|
|
case vvx.IsValid() && vvy.IsValid():
|
|
s.compareAny(vvx, vvy)
|
|
case vvx.IsValid() && !vvy.IsValid():
|
|
s.report(false, vvx, nothing)
|
|
case !vvx.IsValid() && vvy.IsValid():
|
|
s.report(false, nothing, vvy)
|
|
default:
|
|
// It is possible for both vvx and vvy to be invalid if the
|
|
// key contained a NaN value in it. There is no way in
|
|
// reflection to be able to retrieve these values.
|
|
// See https://golang.org/issue/11104
|
|
panic(fmt.Sprintf("%#v has map key with NaNs", s.curPath))
|
|
}
|
|
}
|
|
}
|
|
|
|
func (s *state) compareStruct(vx, vy reflect.Value, t reflect.Type) {
|
|
var vax, vay reflect.Value // Addressable versions of vx and vy
|
|
|
|
step := &structField{}
|
|
s.curPath.push(step)
|
|
defer s.curPath.pop()
|
|
for i := 0; i < t.NumField(); i++ {
|
|
vvx := vx.Field(i)
|
|
vvy := vy.Field(i)
|
|
step.typ = t.Field(i).Type
|
|
step.name = t.Field(i).Name
|
|
step.idx = i
|
|
step.unexported = !isExported(step.name)
|
|
if step.unexported {
|
|
// Defer checking of unexported fields until later to give an
|
|
// Ignore a chance to ignore the field.
|
|
if !vax.IsValid() || !vay.IsValid() {
|
|
// For unsafeRetrieveField to work, the parent struct must
|
|
// be addressable. Create a new copy of the values if
|
|
// necessary to make them addressable.
|
|
vax = makeAddressable(vx)
|
|
vay = makeAddressable(vy)
|
|
}
|
|
step.force = s.exporters[t]
|
|
step.pvx = vax
|
|
step.pvy = vay
|
|
step.field = t.Field(i)
|
|
}
|
|
s.compareAny(vvx, vvy)
|
|
}
|
|
}
|
|
|
|
// report records the result of a single comparison.
|
|
// It also calls Report if any reporter is registered.
|
|
func (s *state) report(eq bool, vx, vy reflect.Value) {
|
|
if eq {
|
|
s.result.NSame++
|
|
} else {
|
|
s.result.NDiff++
|
|
}
|
|
if s.reporter != nil {
|
|
s.reporter.Report(vx, vy, eq, s.curPath)
|
|
}
|
|
}
|
|
|
|
// dynChecker tracks the state needed to periodically perform checks that
|
|
// user provided functions are symmetric and deterministic.
|
|
// The zero value is safe for immediate use.
|
|
type dynChecker struct{ curr, next int }
|
|
|
|
// Next increments the state and reports whether a check should be performed.
|
|
//
|
|
// Checks occur every Nth function call, where N is a triangular number:
|
|
// 0 1 3 6 10 15 21 28 36 45 55 66 78 91 105 120 136 153 171 190 ...
|
|
// See https://en.wikipedia.org/wiki/Triangular_number
|
|
//
|
|
// This sequence ensures that the cost of checks drops significantly as
|
|
// the number of functions calls grows larger.
|
|
func (dc *dynChecker) Next() bool {
|
|
ok := dc.curr == dc.next
|
|
if ok {
|
|
dc.curr = 0
|
|
dc.next++
|
|
}
|
|
dc.curr++
|
|
return ok
|
|
}
|
|
|
|
// makeAddressable returns a value that is always addressable.
|
|
// It returns the input verbatim if it is already addressable,
|
|
// otherwise it creates a new value and returns an addressable copy.
|
|
func makeAddressable(v reflect.Value) reflect.Value {
|
|
if v.CanAddr() {
|
|
return v
|
|
}
|
|
vc := reflect.New(v.Type()).Elem()
|
|
vc.Set(v)
|
|
return vc
|
|
}
|