diff options
Diffstat (limited to 'vendor/github.com/google/go-cmp/cmp/compare.go')
| -rw-r--r-- | vendor/github.com/google/go-cmp/cmp/compare.go | 665 |
1 files changed, 0 insertions, 665 deletions
diff --git a/vendor/github.com/google/go-cmp/cmp/compare.go b/vendor/github.com/google/go-cmp/cmp/compare.go deleted file mode 100644 index 2a5446762..000000000 --- a/vendor/github.com/google/go-cmp/cmp/compare.go +++ /dev/null @@ -1,665 +0,0 @@ -// 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 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. -// It is intended to only be used in tests, as performance is not a goal and -// it may panic if it cannot compare the values. Its propensity towards -// panicking means that its unsuitable for production environments where a -// spurious panic may be fatal. -// -// 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 Exporter option. -package cmp - -import ( - "fmt" - "reflect" - "strings" - - "github.com/google/go-cmp/cmp/internal/diff" - "github.com/google/go-cmp/cmp/internal/function" - "github.com/google/go-cmp/cmp/internal/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: -// -// • 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. -// -// 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 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. -// Empty non-nil slices and nil slices are not equal; to equate empty slices, -// consider using cmpopts.EquateEmpty. -// -// Maps are equal if they are both nil or both non-nil, where recursively -// calling Equal on all non-ignored map entries report equal. -// Map keys are equal according to the == operator. -// To use custom comparisons for map keys, consider using cmpopts.SortMaps. -// Empty non-nil maps and nil maps are not equal; to equate empty maps, -// consider using cmpopts.EquateEmpty. -// -// Pointers and interfaces are equal if they are both nil or both non-nil, -// where they have the same underlying concrete type and recursively -// calling Equal on the underlying values reports equal. -// -// Before recursing into a pointer, slice element, or map, the current path -// is checked to detect whether the address has already been visited. -// If there is a cycle, then the pointed at values are considered equal -// only if both addresses were previously visited in the same path step. -func Equal(x, y interface{}, opts ...Option) bool { - s := newState(opts) - s.compareAny(rootStep(x, y)) - return s.result.Equal() -} - -// Diff returns a human-readable report of the differences between two values: -// y - x. It returns an empty string if and only if Equal returns true for the -// same input values and options. -// -// The output is displayed as a literal in pseudo-Go syntax. -// At the start of each line, a "-" prefix indicates an element removed from x, -// a "+" prefix to indicates an element added from y, and the lack of a prefix -// indicates an element common to both x and y. If possible, the output -// uses fmt.Stringer.String or error.Error methods to produce more humanly -// readable outputs. In such cases, the string is prefixed with either an -// 's' or 'e' character, respectively, to indicate that the method was called. -// -// Do not depend on this output being stable. If you need the ability to -// programmatically interpret the difference, consider using a custom Reporter. -func Diff(x, y interface{}, opts ...Option) string { - s := newState(opts) - - // Optimization: If there are no other reporters, we can optimize for the - // common case where the result is equal (and thus no reported difference). - // This avoids the expensive construction of a difference tree. - if len(s.reporters) == 0 { - s.compareAny(rootStep(x, y)) - if s.result.Equal() { - return "" - } - s.result = diff.Result{} // Reset results - } - - r := new(defaultReporter) - s.reporters = append(s.reporters, reporter{r}) - s.compareAny(rootStep(x, y)) - d := r.String() - if (d == "") != s.result.Equal() { - panic("inconsistent difference and equality results") - } - return d -} - -// rootStep constructs the first path step. If x and y have differing types, -// then they are stored within an empty interface type. -func rootStep(x, y interface{}) PathStep { - vx := reflect.ValueOf(x) - vy := reflect.ValueOf(y) - - // If the inputs are different types, auto-wrap them in an empty interface - // so that they have the same parent type. - var t reflect.Type - if !vx.IsValid() || !vy.IsValid() || vx.Type() != vy.Type() { - t = reflect.TypeOf((*interface{})(nil)).Elem() - if vx.IsValid() { - vvx := reflect.New(t).Elem() - vvx.Set(vx) - vx = vvx - } - if vy.IsValid() { - vvy := reflect.New(t).Elem() - vvy.Set(vy) - vy = vvy - } - } else { - t = vx.Type() - } - - return &pathStep{t, vx, vy} -} - -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 - curPtrs pointerPath // The current set of visited pointers - reporters []reporter // Optional reporters - - // recChecker checks for infinite cycles applying the same set of - // transformers upon the output of itself. - recChecker recChecker - - // 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 []exporter // List of exporters for structs with unexported fields - opts Options // List of all fundamental and filter options -} - -func newState(opts []Option) *state { - // Always ensure a validator option exists to validate the inputs. - s := &state{opts: Options{validator{}}} - s.curPtrs.Init() - s.processOption(Options(opts)) - 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 exporter: - s.exporters = append(s.exporters, opt) - case reporter: - s.reporters = append(s.reporters, 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(step PathStep) diff.Result { - // We do not save and restore curPath and curPtrs because all of the - // compareX methods should properly push and pop from them. - // It is an implementation bug if the contents of the paths differ from - // when calling this function to when returning from it. - - oldResult, oldReporters := s.result, s.reporters - s.result = diff.Result{} // Reset result - s.reporters = nil // Remove reporters to avoid spurious printouts - s.compareAny(step) - res := s.result - s.result, s.reporters = oldResult, oldReporters - return res -} - -func (s *state) compareAny(step PathStep) { - // Update the path stack. - s.curPath.push(step) - defer s.curPath.pop() - for _, r := range s.reporters { - r.PushStep(step) - defer r.PopStep() - } - s.recChecker.Check(s.curPath) - - // Cycle-detection for slice elements (see NOTE in compareSlice). - t := step.Type() - vx, vy := step.Values() - if si, ok := step.(SliceIndex); ok && si.isSlice && vx.IsValid() && vy.IsValid() { - px, py := vx.Addr(), vy.Addr() - if eq, visited := s.curPtrs.Push(px, py); visited { - s.report(eq, reportByCycle) - return - } - defer s.curPtrs.Pop(px, py) - } - - // Rule 1: Check whether an option applies on this node in the value tree. - if s.tryOptions(t, vx, vy) { - return - } - - // Rule 2: Check whether the type has a valid Equal method. - if s.tryMethod(t, vx, vy) { - return - } - - // Rule 3: Compare based on the underlying kind. - switch t.Kind() { - case reflect.Bool: - s.report(vx.Bool() == vy.Bool(), 0) - case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64: - s.report(vx.Int() == vy.Int(), 0) - case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr: - s.report(vx.Uint() == vy.Uint(), 0) - case reflect.Float32, reflect.Float64: - s.report(vx.Float() == vy.Float(), 0) - case reflect.Complex64, reflect.Complex128: - s.report(vx.Complex() == vy.Complex(), 0) - case reflect.String: - s.report(vx.String() == vy.String(), 0) - case reflect.Chan, reflect.UnsafePointer: - s.report(vx.Pointer() == vy.Pointer(), 0) - case reflect.Func: - s.report(vx.IsNil() && vy.IsNil(), 0) - case reflect.Struct: - s.compareStruct(t, vx, vy) - case reflect.Slice, reflect.Array: - s.compareSlice(t, vx, vy) - case reflect.Map: - s.compareMap(t, vx, vy) - case reflect.Ptr: - s.comparePtr(t, vx, vy) - case reflect.Interface: - s.compareInterface(t, vx, vy) - default: - panic(fmt.Sprintf("%v kind not handled", t.Kind())) - } -} - -func (s *state) tryOptions(t reflect.Type, vx, vy reflect.Value) bool { - // Evaluate all filters and apply the remaining options. - if opt := s.opts.filter(s, t, vx, vy); opt != nil { - opt.apply(s, vx, vy) - return true - } - return false -} - -func (s *state) tryMethod(t reflect.Type, vx, vy reflect.Value) 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, reportByMethod) - return true -} - -func (s *state) callTRFunc(f, v reflect.Value, step Transform) reflect.Value { - 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) - got := <-c - want := f.Call([]reflect.Value{v})[0] - if step.vx, step.vy = got, want; !s.statelessCompare(step).Equal() { - // To avoid false-positives with non-reflexive equality operations, - // we sanity check whether a value is equal to itself. - if step.vx, step.vy = want, want; !s.statelessCompare(step).Equal() { - return want - } - panic(fmt.Sprintf("non-deterministic function detected: %s", function.NameOf(f))) - } - return want -} - -func (s *state) callTTBFunc(f, x, y reflect.Value) bool { - 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) - got := <-c - want := f.Call([]reflect.Value{x, y})[0].Bool() - if !got.IsValid() || got.Bool() != want { - panic(fmt.Sprintf("non-deterministic or non-symmetric function detected: %s", function.NameOf(f))) - } - 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] -} - -func (s *state) compareStruct(t reflect.Type, vx, vy reflect.Value) { - var addr bool - 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 - step.vx = vx.Field(i) - step.vy = vy.Field(i) - step.name = t.Field(i).Name - step.idx = i - step.unexported = !isExported(step.name) - if step.unexported { - if step.name == "_" { - continue - } - // Defer checking of unexported fields until later to give an - // Ignore a chance to ignore the field. - if !vax.IsValid() || !vay.IsValid() { - // For retrieveUnexportedField to work, the parent struct must - // be addressable. Create a new copy of the values if - // necessary to make them addressable. - addr = vx.CanAddr() || vy.CanAddr() - vax = makeAddressable(vx) - vay = makeAddressable(vy) - } - if !mayForceInit { - for _, xf := range s.exporters { - mayForce = mayForce || xf(t) - } - mayForceInit = true - } - step.mayForce = mayForce - step.paddr = addr - step.pvx = vax - step.pvy = vay - step.field = t.Field(i) - } - s.compareAny(step) - } -} - -func (s *state) compareSlice(t reflect.Type, vx, vy reflect.Value) { - isSlice := t.Kind() == reflect.Slice - if isSlice && (vx.IsNil() || vy.IsNil()) { - s.report(vx.IsNil() && vy.IsNil(), 0) - return - } - - // NOTE: It is incorrect to call curPtrs.Push on the slice header pointer - // since slices represents a list of pointers, rather than a single pointer. - // The pointer checking logic must be handled on a per-element basis - // in compareAny. - // - // A slice header (see reflect.SliceHeader) in Go is a tuple of a starting - // pointer P, a length N, and a capacity C. Supposing each slice element has - // a memory size of M, then the slice is equivalent to the list of pointers: - // [P+i*M for i in range(N)] - // - // For example, v[:0] and v[:1] are slices with the same starting pointer, - // but they are clearly different values. Using the slice pointer alone - // violates the assumption that equal pointers implies equal values. - - step := SliceIndex{&sliceIndex{pathStep: pathStep{typ: t.Elem()}, isSlice: isSlice}} - withIndexes := func(ix, iy int) SliceIndex { - if ix >= 0 { - step.vx, step.xkey = vx.Index(ix), ix - } else { - step.vx, step.xkey = reflect.Value{}, -1 - } - if iy >= 0 { - step.vy, step.ykey = vy.Index(iy), iy - } else { - step.vy, step.ykey = reflect.Value{}, -1 - } - return step - } - - // Ignore options are able to ignore missing elements in a slice. - // However, detecting these reliably requires an optimal differencing - // algorithm, for which diff.Difference is not. - // - // Instead, we first iterate through both slices to detect which elements - // would be ignored if standing alone. The index of non-discarded elements - // are stored in a separate slice, which diffing is then performed on. - var indexesX, indexesY []int - var ignoredX, ignoredY []bool - for ix := 0; ix < vx.Len(); ix++ { - ignored := s.statelessCompare(withIndexes(ix, -1)).NumDiff == 0 - if !ignored { - indexesX = append(indexesX, ix) - } - ignoredX = append(ignoredX, ignored) - } - for iy := 0; iy < vy.Len(); iy++ { - ignored := s.statelessCompare(withIndexes(-1, iy)).NumDiff == 0 - if !ignored { - indexesY = append(indexesY, iy) - } - ignoredY = append(ignoredY, ignored) - } - - // Compute an edit-script for slices vx and vy (excluding ignored elements). - edits := diff.Difference(len(indexesX), len(indexesY), func(ix, iy int) diff.Result { - return s.statelessCompare(withIndexes(indexesX[ix], indexesY[iy])) - }) - - // Replay the ignore-scripts and the edit-script. - var ix, iy int - for ix < vx.Len() || iy < vy.Len() { - var e diff.EditType - switch { - case ix < len(ignoredX) && ignoredX[ix]: - e = diff.UniqueX - case iy < len(ignoredY) && ignoredY[iy]: - e = diff.UniqueY - default: - e, edits = edits[0], edits[1:] - } - switch e { - case diff.UniqueX: - s.compareAny(withIndexes(ix, -1)) - ix++ - case diff.UniqueY: - s.compareAny(withIndexes(-1, iy)) - iy++ - default: - s.compareAny(withIndexes(ix, iy)) - ix++ - iy++ - } - } -} - -func (s *state) compareMap(t reflect.Type, vx, vy reflect.Value) { - if vx.IsNil() || vy.IsNil() { - s.report(vx.IsNil() && vy.IsNil(), 0) - return - } - - // Cycle-detection for maps. - if eq, visited := s.curPtrs.Push(vx, vy); visited { - s.report(eq, reportByCycle) - return - } - defer s.curPtrs.Pop(vx, vy) - - // We combine and sort the two map keys so that we can perform the - // comparisons in a deterministic order. - step := MapIndex{&mapIndex{pathStep: pathStep{typ: t.Elem()}}} - for _, k := range value.SortKeys(append(vx.MapKeys(), vy.MapKeys()...)) { - step.vx = vx.MapIndex(k) - step.vy = vy.MapIndex(k) - step.key = k - if !step.vx.IsValid() && !step.vy.IsValid() { - // It is possible for both vx and vy to be invalid if the - // key contained a NaN value in it. - // - // Even with the ability to retrieve NaN keys in Go 1.12, - // there still isn't a sensible way to compare the values since - // a NaN key may map to multiple unordered values. - // The most reasonable way to compare NaNs would be to compare the - // set of values. However, this is impossible to do efficiently - // since set equality is provably an O(n^2) operation given only - // an Equal function. If we had a Less function or Hash function, - // this could be done in O(n*log(n)) or O(n), respectively. - // - // Rather than adding complex logic to deal with NaNs, make it - // the user's responsibility to compare such obscure maps. - const help = "consider providing a Comparer to compare the map" - panic(fmt.Sprintf("%#v has map key with NaNs\n%s", s.curPath, help)) - } - s.compareAny(step) - } -} - -func (s *state) comparePtr(t reflect.Type, vx, vy reflect.Value) { - if vx.IsNil() || vy.IsNil() { - s.report(vx.IsNil() && vy.IsNil(), 0) - return - } - - // Cycle-detection for pointers. - if eq, visited := s.curPtrs.Push(vx, vy); visited { - s.report(eq, reportByCycle) - return - } - defer s.curPtrs.Pop(vx, vy) - - vx, vy = vx.Elem(), vy.Elem() - s.compareAny(Indirect{&indirect{pathStep{t.Elem(), vx, vy}}}) -} - -func (s *state) compareInterface(t reflect.Type, vx, vy reflect.Value) { - if vx.IsNil() || vy.IsNil() { - s.report(vx.IsNil() && vy.IsNil(), 0) - return - } - vx, vy = vx.Elem(), vy.Elem() - if vx.Type() != vy.Type() { - s.report(false, 0) - return - } - s.compareAny(TypeAssertion{&typeAssertion{pathStep{vx.Type(), vx, vy}}}) -} - -func (s *state) report(eq bool, rf resultFlags) { - if rf&reportByIgnore == 0 { - if eq { - s.result.NumSame++ - rf |= reportEqual - } else { - s.result.NumDiff++ - rf |= reportUnequal - } - } - for _, r := range s.reporters { - r.Report(Result{flags: rf}) - } -} - -// recChecker tracks the state needed to periodically perform checks that -// user provided transformers are not stuck in an infinitely recursive cycle. -type recChecker struct{ next int } - -// Check scans the Path for any recursive transformers and panics when any -// recursive transformers are detected. Note that the presence of a -// recursive Transformer does not necessarily imply an infinite cycle. -// As such, this check only activates after some minimal number of path steps. -func (rc *recChecker) Check(p Path) { - const minLen = 1 << 16 - if rc.next == 0 { - rc.next = minLen - } - if len(p) < rc.next { - return - } - rc.next <<= 1 - - // Check whether the same transformer has appeared at least twice. - var ss []string - m := map[Option]int{} - for _, ps := range p { - if t, ok := ps.(Transform); ok { - t := t.Option() - if m[t] == 1 { // Transformer was used exactly once before - tf := t.(*transformer).fnc.Type() - ss = append(ss, fmt.Sprintf("%v: %v => %v", t, tf.In(0), tf.Out(0))) - } - m[t]++ - } - } - if len(ss) > 0 { - const warning = "recursive set of Transformers detected" - const help = "consider using cmpopts.AcyclicTransformer" - set := strings.Join(ss, "\n\t") - panic(fmt.Sprintf("%s:\n\t%s\n%s", warning, set, help)) - } -} - -// 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 -} |