package cmp

Import Path
	github.com/google/go-cmp/cmp (on go.dev)

Dependency Relation
	imports 16 packages, and imported by 2 packages


Involved Source Files

	
		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 test's needs,
		    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 with 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.

	      export_unsafe.go
	      options.go
	      path.go
	      report.go
	      report_compare.go
	      report_references.go
	      report_reflect.go
	      report_slices.go
	      report_text.go
	      report_value.go


Code Examples

	
		package main
		
		import (
			"fmt"
			"github.com/google/go-cmp/cmp"
			"net"
			"time"
		)
		
		func main() {
			// Let got be the hypothetical value obtained from some logic under test
			// and want be the expected golden data.
			got, want := MakeGatewayInfo()
		
			if diff := cmp.Diff(want, got); diff != "" {
				t.Errorf("MakeGatewayInfo() mismatch (-want +got):\n%s", diff)
			}
		
		}
		
		type (
			Gateway struct {
				SSID      string
				IPAddress net.IP
				NetMask   net.IPMask
				Clients   []Client
			}
			Client struct {
				Hostname  string
				IPAddress net.IP
				LastSeen  time.Time
			}
		)
		
		func MakeGatewayInfo() (x, y Gateway) {
			x = Gateway{
				SSID:      "CoffeeShopWiFi",
				IPAddress: net.IPv4(192, 168, 0, 1),
				NetMask:   net.IPv4Mask(255, 255, 0, 0),
				Clients: []Client{{
					Hostname:  "ristretto",
					IPAddress: net.IPv4(192, 168, 0, 116),
				}, {
					Hostname:  "aribica",
					IPAddress: net.IPv4(192, 168, 0, 104),
					LastSeen:  time.Date(2009, time.November, 10, 23, 6, 32, 0, time.UTC),
				}, {
					Hostname:  "macchiato",
					IPAddress: net.IPv4(192, 168, 0, 153),
					LastSeen:  time.Date(2009, time.November, 10, 23, 39, 43, 0, time.UTC),
				}, {
					Hostname:  "espresso",
					IPAddress: net.IPv4(192, 168, 0, 121),
				}, {
					Hostname:  "latte",
					IPAddress: net.IPv4(192, 168, 0, 219),
					LastSeen:  time.Date(2009, time.November, 10, 23, 0, 23, 0, time.UTC),
				}, {
					Hostname:  "americano",
					IPAddress: net.IPv4(192, 168, 0, 188),
					LastSeen:  time.Date(2009, time.November, 10, 23, 3, 5, 0, time.UTC),
				}},
			}
			y = Gateway{
				SSID:      "CoffeeShopWiFi",
				IPAddress: net.IPv4(192, 168, 0, 2),
				NetMask:   net.IPv4Mask(255, 255, 0, 0),
				Clients: []Client{{
					Hostname:  "ristretto",
					IPAddress: net.IPv4(192, 168, 0, 116),
				}, {
					Hostname:  "aribica",
					IPAddress: net.IPv4(192, 168, 0, 104),
					LastSeen:  time.Date(2009, time.November, 10, 23, 6, 32, 0, time.UTC),
				}, {
					Hostname:  "macchiato",
					IPAddress: net.IPv4(192, 168, 0, 153),
					LastSeen:  time.Date(2009, time.November, 10, 23, 39, 43, 0, time.UTC),
				}, {
					Hostname:  "espresso",
					IPAddress: net.IPv4(192, 168, 0, 121),
				}, {
					Hostname:  "latte",
					IPAddress: net.IPv4(192, 168, 0, 221),
					LastSeen:  time.Date(2009, time.November, 10, 23, 0, 23, 0, time.UTC),
				}},
			}
			return x, y
		}
		
		var t fakeT
		
		type fakeT struct{}
		
		func (t fakeT) Errorf(format string, args ...interface{}) { fmt.Printf(format+"\n", args...) }

	
		package main
		
		import (
			"fmt"
			"github.com/google/go-cmp/cmp"
			"math"
		)
		
		func main() {
			// This Comparer only operates on float64.
			// To handle float32s, either define a similar function for that type
			// or use a Transformer to convert float32s into float64s.
			opt := cmp.Comparer(func(x, y float64) bool {
				delta := math.Abs(x - y)
				mean := math.Abs(x+y) / 2.0
				return delta/mean < 0.00001
			})
		
			x := []float64{1.0, 1.1, 1.2, math.Pi}
			y := []float64{1.0, 1.1, 1.2, 3.14159265359} // Accurate enough to Pi
			z := []float64{1.0, 1.1, 1.2, 3.1415}        // Diverges too far from Pi
		
			fmt.Println(cmp.Equal(x, y, opt))
			fmt.Println(cmp.Equal(y, z, opt))
			fmt.Println(cmp.Equal(z, x, opt))
		
		}

	
		package main
		
		import (
			"fmt"
			"github.com/google/go-cmp/cmp"
			"strings"
		)
		
		type otherString string
		
		func (x otherString) Equal(y otherString) bool {
			return strings.EqualFold(string(x), string(y))
		}
		
		func main() {
			// Suppose otherString.Equal performs a case-insensitive equality,
			// which is too loose for our needs.
			// We can avoid the methods of otherString by declaring a new type.
			type myString otherString
		
			// This transformer converts otherString to myString, allowing Equal to use
			// other Options to determine equality.
			trans := cmp.Transformer("", func(in otherString) myString {
				return myString(in)
			})
		
			x := []otherString{"foo", "bar", "baz"}
			y := []otherString{"fOO", "bAr", "Baz"} // Same as before, but with different case
		
			fmt.Println(cmp.Equal(x, y))        // Equal because of case-insensitivity
			fmt.Println(cmp.Equal(x, y, trans)) // Not equal because of more exact equality
		
		}

	
		package main
		
		import (
			"fmt"
			"github.com/google/go-cmp/cmp"
			"reflect"
		)
		
		func main() {
			alwaysEqual := cmp.Comparer(func(_, _ interface{}) bool { return true })
		
			// This option handles slices and maps of any type.
			opt := cmp.FilterValues(func(x, y interface{}) bool {
				vx, vy := reflect.ValueOf(x), reflect.ValueOf(y)
				return (vx.IsValid() && vy.IsValid() && vx.Type() == vy.Type()) &&
					(vx.Kind() == reflect.Slice || vx.Kind() == reflect.Map) &&
					(vx.Len() == 0 && vy.Len() == 0)
			}, alwaysEqual)
		
			type S struct {
				A []int
				B map[string]bool
			}
			x := S{nil, make(map[string]bool, 100)}
			y := S{make([]int, 0, 200), nil}
			z := S{[]int{0}, nil} // []int has a single element (i.e., not empty)
		
			fmt.Println(cmp.Equal(x, y, opt))
			fmt.Println(cmp.Equal(y, z, opt))
			fmt.Println(cmp.Equal(z, x, opt))
		
		}

	
		package main
		
		import (
			"fmt"
			"github.com/google/go-cmp/cmp"
			"math"
		)
		
		func main() {
			// This Comparer only operates on float64.
			// To handle float32s, either define a similar function for that type
			// or use a Transformer to convert float32s into float64s.
			opt := cmp.Comparer(func(x, y float64) bool {
				return (math.IsNaN(x) && math.IsNaN(y)) || x == y
			})
		
			x := []float64{1.0, math.NaN(), math.E, 0.0}
			y := []float64{1.0, math.NaN(), math.E, 0.0}
			z := []float64{1.0, math.NaN(), math.Pi, 0.0} // Pi constant instead of E
		
			fmt.Println(cmp.Equal(x, y, opt))
			fmt.Println(cmp.Equal(y, z, opt))
			fmt.Println(cmp.Equal(z, x, opt))
		
		}

	
		package main
		
		import (
			"fmt"
			"github.com/google/go-cmp/cmp"
			"math"
		)
		
		func main() {
			alwaysEqual := cmp.Comparer(func(_, _ interface{}) bool { return true })
		
			opts := cmp.Options{
				// This option declares that a float64 comparison is equal only if
				// both inputs are NaN.
				cmp.FilterValues(func(x, y float64) bool {
					return math.IsNaN(x) && math.IsNaN(y)
				}, alwaysEqual),
		
				// This option declares approximate equality on float64s only if
				// both inputs are not NaN.
				cmp.FilterValues(func(x, y float64) bool {
					return !math.IsNaN(x) && !math.IsNaN(y)
				}, cmp.Comparer(func(x, y float64) bool {
					delta := math.Abs(x - y)
					mean := math.Abs(x+y) / 2.0
					return delta/mean < 0.00001
				})),
			}
		
			x := []float64{math.NaN(), 1.0, 1.1, 1.2, math.Pi}
			y := []float64{math.NaN(), 1.0, 1.1, 1.2, 3.14159265359} // Accurate enough to Pi
			z := []float64{math.NaN(), 1.0, 1.1, 1.2, 3.1415}        // Diverges too far from Pi
		
			fmt.Println(cmp.Equal(x, y, opts))
			fmt.Println(cmp.Equal(y, z, opts))
			fmt.Println(cmp.Equal(z, x, opts))
		
		}

	
		package main
		
		import (
			"fmt"
			"github.com/google/go-cmp/cmp"
			"sort"
		)
		
		func main() {
			// This Transformer sorts a []int.
			trans := cmp.Transformer("Sort", func(in []int) []int {
				out := append([]int(nil), in...) // Copy input to avoid mutating it
				sort.Ints(out)
				return out
			})
		
			x := struct{ Ints []int }{[]int{0, 1, 2, 3, 4, 5, 6, 7, 8, 9}}
			y := struct{ Ints []int }{[]int{2, 8, 0, 9, 6, 1, 4, 7, 3, 5}}
			z := struct{ Ints []int }{[]int{0, 0, 1, 2, 3, 4, 5, 6, 7, 8}}
		
			fmt.Println(cmp.Equal(x, y, trans))
			fmt.Println(cmp.Equal(y, z, trans))
			fmt.Println(cmp.Equal(z, x, trans))
		
		}

	
		package main
		
		import (
			"fmt"
			"github.com/google/go-cmp/cmp"
			"math"
		)
		
		func roundF64(z float64) float64 {
			if z < 0 {
				return math.Ceil(z - 0.5)
			}
			return math.Floor(z + 0.5)
		}
		
		func main() {
			opts := []cmp.Option{
				// This transformer decomposes complex128 into a pair of float64s.
				cmp.Transformer("T1", func(in complex128) (out struct{ Real, Imag float64 }) {
					out.Real, out.Imag = real(in), imag(in)
					return out
				}),
				// This transformer converts complex64 to complex128 to allow the
				// above transform to take effect.
				cmp.Transformer("T2", func(in complex64) complex128 {
					return complex128(in)
				}),
				// This transformer converts float32 to float64.
				cmp.Transformer("T3", func(in float32) float64 {
					return float64(in)
				}),
				// This equality function compares float64s as rounded integers.
				cmp.Comparer(func(x, y float64) bool {
					return roundF64(x) == roundF64(y)
				}),
			}
		
			x := []interface{}{
				complex128(3.0), complex64(5.1 + 2.9i), float32(-1.2), float64(12.3),
			}
			y := []interface{}{
				complex128(3.1), complex64(4.9 + 3.1i), float32(-1.3), float64(11.7),
			}
			z := []interface{}{
				complex128(3.8), complex64(4.9 + 3.1i), float32(-1.3), float64(11.7),
			}
		
			fmt.Println(cmp.Equal(x, y, opts...))
			fmt.Println(cmp.Equal(y, z, opts...))
			fmt.Println(cmp.Equal(z, x, opts...))
		
		}

	
		package main
		
		import (
			"fmt"
			"strings"
		
			"github.com/google/go-cmp/cmp"
		)
		
		// DiffReporter is a simple custom reporter that only records differences
		// detected during comparison.
		type DiffReporter struct {
			path  cmp.Path
			diffs []string
		}
		
		func (r *DiffReporter) PushStep(ps cmp.PathStep) {
			r.path = append(r.path, ps)
		}
		
		func (r *DiffReporter) Report(rs cmp.Result) {
			if !rs.Equal() {
				vx, vy := r.path.Last().Values()
				r.diffs = append(r.diffs, fmt.Sprintf("%#v:\n\t-: %+v\n\t+: %+v\n", r.path, vx, vy))
			}
		}
		
		func (r *DiffReporter) PopStep() {
			r.path = r.path[:len(r.path)-1]
		}
		
		func (r *DiffReporter) String() string {
			return strings.Join(r.diffs, "\n")
		}
		
		func main() {
			x, y := MakeGatewayInfo()
		
			var r DiffReporter
			cmp.Equal(x, y, cmp.Reporter(&r))
			fmt.Print(r.String())
		
		}




Package-Level Type Names (total 55, in which 11 are exported)


	/* sort exporteds by:  |  */
	
		Indirect represents pointer indirection on the parent type.

		
			
		
			( Indirect) String() string
			( Indirect) Type() reflect.Type
			( Indirect) Values() (vx, vy reflect.Value)
		
			 Indirect : PathStep
			 Indirect : expvar.Var
			 Indirect : fmt.Stringer
			


	
		MapIndex is an index operation on a map at some index Key.

		
			
		
			
				Key is the value of the map key.

			( MapIndex) String() string
			( MapIndex) Type() reflect.Type
			( MapIndex) Values() (vx, vy reflect.Value)
		
			 MapIndex : PathStep
			 MapIndex : expvar.Var
			 MapIndex : fmt.Stringer
			


	
		Option configures for specific behavior of Equal and Diff. In particular,
		the fundamental Option functions (Ignore, Transformer, and Comparer),
		configure how equality is determined.

		The fundamental options may be composed with filters (FilterPath and
		FilterValues) to control the scope over which they are applied.

		The cmp/cmpopts package provides helper functions for creating options that
		may be used with Equal and Diff.

		
			
		
			 Options
			
		
			func AllowUnexported(types ...interface{}) Option
			func Comparer(f interface{}) Option
			func Exporter(f func(reflect.Type) bool) Option
			func FilterPath(f func(Path) bool, opt Option) Option
			func FilterValues(f interface{}, opt Option) Option
			func Ignore() Option
			func Reporter(r interface{PushStep(PathStep); Report(Result); PopStep()}) Option
			func Transformer(name string, f interface{}) Option
			func Transform.Option() Option
			
		
			func Diff(x, y interface{}, opts ...Option) string
			func Equal(x, y interface{}, opts ...Option) bool
			func FilterPath(f func(Path) bool, opt Option) Option
			func FilterValues(f interface{}, opt Option) Option
			func gotest.tools/v3/assert.DeepEqual(t assert.TestingT, x, y interface{}, opts ...Option)
			func gotest.tools/v3/assert/cmp.DeepEqual(x, y interface{}, opts ...Option) cmp.Comparison
			


	
		Options is a list of Option values that also satisfies the Option interface.
		Helper comparison packages may return an Options value when packing multiple
		Option values into a single Option. When this package processes an Options,
		it will be implicitly expanded into a flat list.

		Applying a filter on an Options is equivalent to applying that same filter
		on all individual options held within.

		
			( Options) String() string
			
		
			 Options : Option
			 Options : expvar.Var
			 Options : fmt.Stringer
			
		
			
		
			


	
		Path is a list of PathSteps describing the sequence of operations to get
		from some root type to the current position in the value tree.
		The first Path element is always an operation-less PathStep that exists
		simply to identify the initial type.

		When traversing structs with embedded structs, the embedded struct will
		always be accessed as a field before traversing the fields of the
		embedded struct themselves. That is, an exported field from the
		embedded struct will never be accessed directly from the parent struct.

		
			
				GoString returns the path to a specific node using Go syntax.

				For example:

					(*root.MyMap["key"].(*mypkg.MyStruct).MySlices)[2][3].MyField

			
				Index returns the ith step in the Path and supports negative indexing.
				A negative index starts counting from the tail of the Path such that -1
				refers to the last step, -2 refers to the second-to-last step, and so on.
				If index is invalid, this returns a non-nil PathStep that reports a nil Type.

			
				Last returns the last PathStep in the Path.
				If the path is empty, this returns a non-nil PathStep that reports a nil Type.

			
				String returns the simplified path to a node.
				The simplified path only contains struct field accesses.

				For example:

					MyMap.MySlices.MyField

			
		
			 Path : expvar.Var
			 Path : fmt.GoStringer
			 Path : fmt.Stringer
			


	
		PathStep is a union-type for specific operations to traverse
		a value's tree structure. Users of this package never need to implement
		these types as values of this type will be returned by this package.

		Implementations of this interface are
		StructField, SliceIndex, MapIndex, Indirect, TypeAssertion, and Transform.

		
			( PathStep) String() string
			
				Type is the resulting type after performing the path step.

			
				Values is the resulting values after performing the path step.
				The type of each valid value is guaranteed to be identical to Type.

				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
				    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
				    either the x or y map.

				The provided values must not be mutated.

		
			 Indirect
			 MapIndex
			 SliceIndex
			 StructField
			 Transform
			 TypeAssertion
			
		
			 PathStep : expvar.Var
			 PathStep : fmt.Stringer
			
		
			func Path.Index(i int) PathStep
			func Path.Last() PathStep
			
		
			


	
		Result represents the comparison result for a single node and
		is provided by cmp when calling Report (see Reporter).

		
			
		
			
				ByCycle reports whether a reference cycle was detected.

			
				ByFunc reports whether a Comparer function determined equality.

			
				ByIgnore reports whether the node is equal because it was ignored.
				This never reports true if Equal reports false.

			
				ByMethod reports whether the Equal method determined equality.

			
				Equal reports whether the node was determined to be equal or not.
				As a special case, ignored nodes are considered equal.



	
		SliceIndex is an index operation on a slice or array at some index Key.

		
			
		
			
				Key is the index key; it may return -1 if in a split state

			
				SplitKeys are the indexes for indexing into slices in the
				x and y values, respectively. These indexes may differ due to the
				insertion or removal of an element in one of the slices, causing
				all of the indexes to be shifted. If an index is -1, then that
				indicates that the element does not exist in the associated slice.

				Key is guaranteed to return -1 if and only if the indexes returned
				by SplitKeys are not the same. SplitKeys will never return -1 for
				both indexes.

			( SliceIndex) String() string
			( SliceIndex) Type() reflect.Type
			( SliceIndex) Values() (vx, vy reflect.Value)
		
			 SliceIndex : PathStep
			 SliceIndex : expvar.Var
			 SliceIndex : fmt.Stringer
			


	
		StructField represents a struct field access on a field called Name.

		
			
		
			
				Index is the index of the field in the parent struct type.
				See reflect.Type.Field.

			
				Name is the field name.

			( StructField) String() string
			( StructField) Type() reflect.Type
			( StructField) Values() (vx, vy reflect.Value)
		
			 StructField : PathStep
			 StructField : expvar.Var
			 StructField : fmt.Stringer
			


	
		Transform is a transformation from the parent type to the current type.

		
			
		
			
				Func is the function pointer to the transformer function.

			
				Name is the name of the Transformer.

			
				Option returns the originally constructed Transformer option.
				The == operator can be used to detect the exact option used.

			( Transform) String() string
			( Transform) Type() reflect.Type
			( Transform) Values() (vx, vy reflect.Value)
		
			 Transform : PathStep
			 Transform : expvar.Var
			 Transform : fmt.Stringer
			


	
		TypeAssertion represents a type assertion on an interface.

		
			
		
			( TypeAssertion) String() string
			( TypeAssertion) Type() reflect.Type
			( TypeAssertion) Values() (vx, vy reflect.Value)
		
			 TypeAssertion : PathStep
			 TypeAssertion : expvar.Var
			 TypeAssertion : fmt.Stringer
			


	


Package-Level Functions (total 36, in which 10 are exported)


	
		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.


	
		Comparer returns an Option that determines whether two values are equal
		to each other.

		The comparer f must be a function "func(T, T) bool" and is implicitly
		filtered to input values assignable to T. If T is an interface, it is
		possible that f is called with two values of different concrete types that
		both implement T.

		The equality function must be:
		  - Symmetric: equal(x, y) == equal(y, x)
		  - Deterministic: equal(x, y) == equal(x, y)
		  - Pure: equal(x, y) does not modify x or y


	
		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.


	
		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 non-zero,
		    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.


	
		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
		implementation of some external package may cause the result of Equal
		to unexpectedly change. However, it may be valid to use this option on types
		defined in an internal package where the semantic meaning of an unexported
		field is in the control of the user.

		In many cases, a custom Comparer should be used instead that defines
		equality as a function of the public API of a type rather than the underlying
		unexported implementation.

		For example, the reflect.Type documentation defines equality to be determined
		by the == operator on the interface (essentially performing a shallow pointer
		comparison) and most attempts to compare *regexp.Regexp types are interested
		in only checking that the regular expression strings are equal.
		Both of these are accomplished using Comparers:

			Comparer(func(x, y reflect.Type) bool { return x == y })
			Comparer(func(x, y *regexp.Regexp) bool { return x.String() == y.String() })

		In other cases, the cmpopts.IgnoreUnexported option can be used to ignore
		all unexported fields on specified struct types.


	
		FilterPath returns a new Option where opt is only evaluated if filter f
		returns true for the current Path in the value tree.

		This filter is called even if a slice element or map entry is missing and
		provides an opportunity to ignore such cases. The filter function must be
		symmetric such that the filter result is identical regardless of whether the
		missing value is from x or y.

		The option passed in may be an Ignore, Transformer, Comparer, Options, or
		a previously filtered Option.


	
		FilterValues returns a new Option where opt is only evaluated if filter f,
		which is a function of the form "func(T, T) bool", returns true for the
		current pair of values being compared. If either value is invalid or
		the type of the values is not assignable to T, then this filter implicitly
		returns false.

		The filter function must be
		symmetric (i.e., agnostic to the order of the inputs) and
		deterministic (i.e., produces the same result when given the same inputs).
		If T is an interface, it is possible that f is called with two values with
		different concrete types that both implement T.

		The option passed in may be an Ignore, Transformer, Comparer, Options, or
		a previously filtered Option.


	
		Ignore is an Option that causes all comparisons to be ignored.
		This value is intended to be combined with FilterPath or FilterValues.
		It is an error to pass an unfiltered Ignore option to Equal.


	
		Reporter is an Option that can be passed to Equal. When Equal traverses
		the value trees, it calls PushStep as it descends into each node in the
		tree and PopStep as it ascend out of the node. The leaves of the tree are
		either compared (determined to be equal or not equal) or ignored and reported
		as such by calling the Report method.


	
		Transformer returns an Option that applies a transformation function that
		converts values of a certain type into that of another.

		The transformer f must be a function "func(T) R" that converts values of
		type T to those of type R and is implicitly filtered to input values
		assignable to T. The transformer must not mutate T in any way.

		To help prevent some cases of infinite recursive cycles applying the
		same transform to the output of itself (e.g., in the case where the
		input and output types are the same), an implicit filter is added such that
		a transformer is applicable only if that exact transformer is not already
		in the tail of the Path since the last non-Transform step.
		For situations where the implicit filter is still insufficient,
		consider using cmpopts.AcyclicTransformer, which adds a filter
		to prevent the transformer from being recursively applied upon itself.

		The name is a user provided label that is used as the Transform.Name in the
		transformation PathStep (and eventually shown in the Diff output).
		The name must be a valid identifier or qualified identifier in Go syntax.
		If empty, an arbitrary name is used.


	


Package-Level Variables (total 8, none are exported)

	


Package-Level Constants (total 20, none are exported)