diff options
Diffstat (limited to 'cmp/compare.go')
| -rw-r--r-- | cmp/compare.go | 66 |
1 files changed, 35 insertions, 31 deletions
diff --git a/cmp/compare.go b/cmp/compare.go index 2a54467..087320d 100644 --- a/cmp/compare.go +++ b/cmp/compare.go @@ -13,21 +13,21 @@ // // 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. +// - 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 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. +// - 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. +// - 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 ( @@ -40,28 +40,30 @@ import ( "github.com/google/go-cmp/cmp/internal/value" ) +// TODO(≥go1.18): Use any instead of interface{}. + // 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. +// - 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. +// - 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. +// - 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 @@ -142,7 +144,7 @@ func rootStep(x, y interface{}) PathStep { // 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() + t = anyType if vx.IsValid() { vvx := reflect.New(t).Elem() vvx.Set(vx) @@ -637,7 +639,9 @@ 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 |