Updates #12736 Signed-off-by: Nick Khyl <nickk@tailscale.com>main
Nick Khyl
2 years ago
committed by
Nick Khyl
parent
5576972261
commit
e21d8768f9
@ -0,0 +1,122 @@ |
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// Copyright (c) Tailscale Inc & AUTHORS
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// SPDX-License-Identifier: BSD-3-Clause
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package opt |
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import ( |
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"fmt" |
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"reflect" |
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jsonv2 "github.com/go-json-experiment/json" |
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"github.com/go-json-experiment/json/jsontext" |
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) |
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// Value is an optional value to be JSON-encoded.
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// With [encoding/json], a zero Value is marshaled as a JSON null.
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// With [github.com/go-json-experiment/json], a zero Value is omitted from the
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// JSON object if the Go struct field specified with omitzero.
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// The omitempty tag option should never be used with Value fields.
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type Value[T any] struct { |
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value T |
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set bool |
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} |
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// Equal reports whether the receiver and the other value are equal.
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// If the template type T in Value[T] implements an Equal method, it will be used
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// instead of the == operator for comparing values.
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type equatable[T any] interface { |
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// Equal reports whether the receiver and the other values are equal.
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Equal(other T) bool |
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} |
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// ValueOf returns an optional Value containing the specified value.
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// It treats nil slices and maps as empty slices and maps.
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func ValueOf[T any](v T) Value[T] { |
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return Value[T]{value: v, set: true} |
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} |
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// String implements [fmt.Stringer].
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func (o *Value[T]) String() string { |
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if !o.set { |
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return fmt.Sprintf("(empty[%T])", o.value) |
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} |
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return fmt.Sprint(o.value) |
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} |
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// Set assigns the specified value to the optional value o.
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func (o *Value[T]) Set(v T) { |
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*o = ValueOf(v) |
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} |
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// Clear resets o to an empty state.
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func (o *Value[T]) Clear() { |
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*o = Value[T]{} |
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} |
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// IsSet reports whether o has a value set.
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func (o *Value[T]) IsSet() bool { |
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return o.set |
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} |
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// Get returns the value of o.
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// If a value hasn't been set, a zero value of T will be returned.
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func (o Value[T]) Get() T { |
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return o.value |
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} |
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// Get returns the value and a flag indicating whether the value is set.
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func (o Value[T]) GetOk() (v T, ok bool) { |
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return o.value, o.set |
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} |
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// Equal reports whether o is equal to v.
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// Two optional values are equal if both are empty,
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// or if both are set and the underlying values are equal.
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// If the template type T implements an Equal(T) bool method, it will be used
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// instead of the == operator for value comparison.
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// If T is not comparable, it returns false.
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func (o Value[T]) Equal(v Value[T]) bool { |
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if o.set != v.set { |
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return false |
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} |
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if !o.set { |
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return true |
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} |
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ov := any(o.value) |
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if eq, ok := ov.(equatable[T]); ok { |
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return eq.Equal(v.value) |
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} |
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if reflect.TypeFor[T]().Comparable() { |
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return ov == any(v.value) |
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} |
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return false |
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} |
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// MarshalJSONV2 implements [jsonv2.MarshalerV2].
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func (o Value[T]) MarshalJSONV2(enc *jsontext.Encoder, opts jsonv2.Options) error { |
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if !o.set { |
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return enc.WriteToken(jsontext.Null) |
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} |
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return jsonv2.MarshalEncode(enc, &o.value, opts) |
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} |
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// UnmarshalJSONV2 implements [jsonv2.UnmarshalerV2].
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func (o *Value[T]) UnmarshalJSONV2(dec *jsontext.Decoder, opts jsonv2.Options) error { |
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if dec.PeekKind() == 'n' { |
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*o = Value[T]{} |
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_, err := dec.ReadToken() // read null
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return err |
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} |
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o.set = true |
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return jsonv2.UnmarshalDecode(dec, &o.value, opts) |
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} |
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// MarshalJSON implements [json.Marshaler].
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func (o Value[T]) MarshalJSON() ([]byte, error) { |
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return jsonv2.Marshal(o) // uses MarshalJSONV2
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} |
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// UnmarshalJSON implements [json.Unmarshaler].
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func (o *Value[T]) UnmarshalJSON(b []byte) error { |
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return jsonv2.Unmarshal(b, o) // uses UnmarshalJSONV2
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} |
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@ -0,0 +1,296 @@ |
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// Copyright (c) Tailscale Inc & AUTHORS
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// SPDX-License-Identifier: BSD-3-Clause
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package opt |
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import ( |
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"encoding/json" |
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"reflect" |
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"testing" |
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jsonv2 "github.com/go-json-experiment/json" |
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) |
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type testStruct struct { |
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Int int `json:",omitempty,omitzero"` |
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Str string `json:",omitempty"` |
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} |
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func TestValue(t *testing.T) { |
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tests := []struct { |
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name string |
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in any |
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jsonv2 bool |
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want string // JSON
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wantBack any |
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}{ |
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{ |
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name: "null_for_unset", |
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in: struct { |
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True Value[bool] |
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False Value[bool] |
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Unset Value[bool] |
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ExplicitUnset Value[bool] |
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}{ |
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True: ValueOf(true), |
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False: ValueOf(false), |
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ExplicitUnset: Value[bool]{}, |
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}, |
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want: `{"True":true,"False":false,"Unset":null,"ExplicitUnset":null}`, |
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wantBack: struct { |
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True Value[bool] |
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False Value[bool] |
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Unset Value[bool] |
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ExplicitUnset Value[bool] |
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}{ |
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True: ValueOf(true), |
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False: ValueOf(false), |
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Unset: Value[bool]{}, |
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ExplicitUnset: Value[bool]{}, |
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}, |
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}, |
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{ |
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name: "null_for_unset_jsonv2", |
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in: struct { |
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True Value[bool] |
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False Value[bool] |
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Unset Value[bool] |
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ExplicitUnset Value[bool] |
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}{ |
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True: ValueOf(true), |
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False: ValueOf(false), |
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ExplicitUnset: Value[bool]{}, |
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}, |
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jsonv2: true, |
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want: `{"True":true,"False":false,"Unset":null,"ExplicitUnset":null}`, |
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wantBack: struct { |
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True Value[bool] |
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False Value[bool] |
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Unset Value[bool] |
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ExplicitUnset Value[bool] |
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}{ |
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True: ValueOf(true), |
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False: ValueOf(false), |
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Unset: Value[bool]{}, |
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ExplicitUnset: Value[bool]{}, |
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}, |
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}, |
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{ |
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name: "null_for_unset_omitzero", |
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in: struct { |
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True Value[bool] `json:",omitzero"` |
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False Value[bool] `json:",omitzero"` |
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Unset Value[bool] `json:",omitzero"` |
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ExplicitUnset Value[bool] `json:",omitzero"` |
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}{ |
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True: ValueOf(true), |
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False: ValueOf(false), |
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ExplicitUnset: Value[bool]{}, |
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}, |
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want: `{"True":true,"False":false,"Unset":null,"ExplicitUnset":null}`, |
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wantBack: struct { |
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True Value[bool] `json:",omitzero"` |
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False Value[bool] `json:",omitzero"` |
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Unset Value[bool] `json:",omitzero"` |
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ExplicitUnset Value[bool] `json:",omitzero"` |
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}{ |
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True: ValueOf(true), |
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False: ValueOf(false), |
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Unset: Value[bool]{}, |
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ExplicitUnset: Value[bool]{}, |
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}, |
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}, |
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{ |
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name: "null_for_unset_omitzero_jsonv2", |
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in: struct { |
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True Value[bool] `json:",omitzero"` |
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False Value[bool] `json:",omitzero"` |
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Unset Value[bool] `json:",omitzero"` |
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ExplicitUnset Value[bool] `json:",omitzero"` |
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}{ |
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True: ValueOf(true), |
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False: ValueOf(false), |
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ExplicitUnset: Value[bool]{}, |
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}, |
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jsonv2: true, |
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want: `{"True":true,"False":false}`, |
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wantBack: struct { |
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True Value[bool] `json:",omitzero"` |
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False Value[bool] `json:",omitzero"` |
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Unset Value[bool] `json:",omitzero"` |
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ExplicitUnset Value[bool] `json:",omitzero"` |
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}{ |
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True: ValueOf(true), |
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False: ValueOf(false), |
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Unset: Value[bool]{}, |
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ExplicitUnset: Value[bool]{}, |
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}, |
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}, |
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{ |
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name: "string", |
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in: struct { |
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EmptyString Value[string] |
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NonEmpty Value[string] |
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Unset Value[string] |
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}{ |
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EmptyString: ValueOf(""), |
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NonEmpty: ValueOf("value"), |
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Unset: Value[string]{}, |
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}, |
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want: `{"EmptyString":"","NonEmpty":"value","Unset":null}`, |
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wantBack: struct { |
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EmptyString Value[string] |
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NonEmpty Value[string] |
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Unset Value[string] |
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}{ValueOf(""), ValueOf("value"), Value[string]{}}, |
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}, |
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{ |
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name: "integer", |
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in: struct { |
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Zero Value[int] |
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NonZero Value[int] |
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Unset Value[int] |
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}{ |
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Zero: ValueOf(0), |
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NonZero: ValueOf(42), |
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Unset: Value[int]{}, |
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}, |
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want: `{"Zero":0,"NonZero":42,"Unset":null}`, |
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wantBack: struct { |
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Zero Value[int] |
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NonZero Value[int] |
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Unset Value[int] |
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}{ValueOf(0), ValueOf(42), Value[int]{}}, |
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}, |
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{ |
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name: "struct", |
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in: struct { |
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Zero Value[testStruct] |
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NonZero Value[testStruct] |
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Unset Value[testStruct] |
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}{ |
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Zero: ValueOf(testStruct{}), |
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NonZero: ValueOf(testStruct{Int: 42, Str: "String"}), |
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Unset: Value[testStruct]{}, |
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}, |
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want: `{"Zero":{},"NonZero":{"Int":42,"Str":"String"},"Unset":null}`, |
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wantBack: struct { |
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Zero Value[testStruct] |
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NonZero Value[testStruct] |
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Unset Value[testStruct] |
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}{ValueOf(testStruct{}), ValueOf(testStruct{Int: 42, Str: "String"}), Value[testStruct]{}}, |
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}, |
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{ |
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name: "struct_ptr", |
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in: struct { |
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Zero Value[*testStruct] |
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NonZero Value[*testStruct] |
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Unset Value[*testStruct] |
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}{ |
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Zero: ValueOf(&testStruct{}), |
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NonZero: ValueOf(&testStruct{Int: 42, Str: "String"}), |
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Unset: Value[*testStruct]{}, |
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}, |
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want: `{"Zero":{},"NonZero":{"Int":42,"Str":"String"},"Unset":null}`, |
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wantBack: struct { |
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Zero Value[*testStruct] |
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NonZero Value[*testStruct] |
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Unset Value[*testStruct] |
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}{ValueOf(&testStruct{}), ValueOf(&testStruct{Int: 42, Str: "String"}), Value[*testStruct]{}}, |
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}, |
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{ |
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name: "nil-slice-and-map", |
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in: struct { |
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Slice Value[[]int] |
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Map Value[map[string]int] |
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}{ |
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Slice: ValueOf[[]int](nil), // marshalled as []
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Map: ValueOf[map[string]int](nil), // marshalled as {}
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}, |
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want: `{"Slice":[],"Map":{}}`, |
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wantBack: struct { |
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Slice Value[[]int] |
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Map Value[map[string]int] |
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}{ValueOf([]int{}), ValueOf(map[string]int{})}, |
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}, |
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} |
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for _, tt := range tests { |
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t.Run(tt.name, func(t *testing.T) { |
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var j []byte |
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var err error |
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if tt.jsonv2 { |
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j, err = jsonv2.Marshal(tt.in) |
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} else { |
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j, err = json.Marshal(tt.in) |
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} |
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if err != nil { |
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t.Fatal(err) |
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} |
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if string(j) != tt.want { |
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t.Errorf("wrong JSON:\n got: %s\nwant: %s\n", j, tt.want) |
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} |
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wantBack := tt.in |
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if tt.wantBack != nil { |
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wantBack = tt.wantBack |
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} |
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// And back again:
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newVal := reflect.New(reflect.TypeOf(tt.in)) |
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out := newVal.Interface() |
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if tt.jsonv2 { |
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err = jsonv2.Unmarshal(j, out) |
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} else { |
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err = json.Unmarshal(j, out) |
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} |
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if err != nil { |
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t.Fatalf("Unmarshal %#q: %v", j, err) |
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} |
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got := newVal.Elem().Interface() |
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if !reflect.DeepEqual(got, wantBack) { |
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t.Errorf("value mismatch\n got: %+v\nwant: %+v\n", got, wantBack) |
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} |
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}) |
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} |
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} |
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func TestValueEqual(t *testing.T) { |
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tests := []struct { |
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o Value[bool] |
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v Value[bool] |
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want bool |
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}{ |
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{ValueOf(true), ValueOf(true), true}, |
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{ValueOf(true), ValueOf(false), false}, |
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{ValueOf(true), Value[bool]{}, false}, |
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{ValueOf(false), ValueOf(false), true}, |
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{ValueOf(false), ValueOf(true), false}, |
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{ValueOf(false), Value[bool]{}, false}, |
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{Value[bool]{}, Value[bool]{}, true}, |
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{Value[bool]{}, ValueOf(true), false}, |
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{Value[bool]{}, ValueOf(false), false}, |
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} |
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for _, tt := range tests { |
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if got := tt.o.Equal(tt.v); got != tt.want { |
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t.Errorf("(%v).Equals(%v) = %v; want %v", tt.o, tt.v, got, tt.want) |
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} |
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} |
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} |
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func TestIncomparableValueEqual(t *testing.T) { |
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tests := []struct { |
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o Value[[]bool] |
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v Value[[]bool] |
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want bool |
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}{ |
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{ValueOf([]bool{}), ValueOf([]bool{}), false}, |
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{ValueOf([]bool{true}), ValueOf([]bool{true}), false}, |
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{Value[[]bool]{}, ValueOf([]bool{}), false}, |
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{ValueOf([]bool{}), Value[[]bool]{}, false}, |
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{Value[[]bool]{}, Value[[]bool]{}, true}, |
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} |
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for _, tt := range tests { |
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if got := tt.o.Equal(tt.v); got != tt.want { |
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t.Errorf("(%v).Equals(%v) = %v; want %v", tt.o, tt.v, got, tt.want) |
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} |
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} |
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} |
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