mirror of
https://github.com/gohugoio/hugo.git
synced 2024-12-27 21:02:11 +00:00
02eaddc2fb
Before this commit, due to a bug in Go's `text/template` package, this would print different output for typed nil interface values:
```
{{ if .AuthenticatedUser }}User is authenticated!{{ else }}{{ end }}
{{ if not .AuthenticatedUser }}{{ else }}}User is authenticated!{{ end }}
```
This commit works around this by wrapping every `if` and `with` with a custom `getif` template func with truth logic that matches `not`, `and` and `or`.
Those 3 template funcs from Go's stdlib are now pulled into Hugo's source tree and adjusted to support custom zero values, e.g. types that implement `IsZero`.
This means that you can now do:
```
{{ with .Date }}{{ . }}{{ end }}
```
And it would work as expected.
Fixes #5738
91 lines
2.8 KiB
Go
91 lines
2.8 KiB
Go
// Copyright 2019 The Hugo Authors. All rights reserved.
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// Some functions in this file (see comments) is based on the Go source code,
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// copyright The Go Authors and governed by a BSD-style license.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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// Package hreflect contains reflect helpers.
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package hreflect
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import (
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"reflect"
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"github.com/gohugoio/hugo/common/types"
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)
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// IsTruthful returns whether in represents a truthful value.
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// See IsTruthfulValue
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func IsTruthful(in interface{}) bool {
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switch v := in.(type) {
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case reflect.Value:
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return IsTruthfulValue(v)
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default:
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return IsTruthfulValue(reflect.ValueOf(in))
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}
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}
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var zeroType = reflect.TypeOf((*types.Zeroer)(nil)).Elem()
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// IsTruthfulValue returns whether the given value has a meaningful truth value.
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// This is based on template.IsTrue in Go's stdlib, but also considers
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// IsZero and any interface value will be unwrapped before it's considered
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// for truthfulness.
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//
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// Based on:
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// https://github.com/golang/go/blob/178a2c42254166cffed1b25fb1d3c7a5727cada6/src/text/template/exec.go#L306
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func IsTruthfulValue(val reflect.Value) (truth bool) {
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val = indirectInterface(val)
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if !val.IsValid() {
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// Something like var x interface{}, never set. It's a form of nil.
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return
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}
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if val.Type().Implements(zeroType) {
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return !val.Interface().(types.Zeroer).IsZero()
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}
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switch val.Kind() {
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case reflect.Array, reflect.Map, reflect.Slice, reflect.String:
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truth = val.Len() > 0
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case reflect.Bool:
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truth = val.Bool()
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case reflect.Complex64, reflect.Complex128:
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truth = val.Complex() != 0
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case reflect.Chan, reflect.Func, reflect.Ptr, reflect.Interface:
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truth = !val.IsNil()
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case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
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truth = val.Int() != 0
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case reflect.Float32, reflect.Float64:
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truth = val.Float() != 0
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case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
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truth = val.Uint() != 0
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case reflect.Struct:
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truth = true // Struct values are always true.
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default:
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return
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}
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return
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}
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// Based on: https://github.com/golang/go/blob/178a2c42254166cffed1b25fb1d3c7a5727cada6/src/text/template/exec.go#L931
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func indirectInterface(v reflect.Value) reflect.Value {
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if v.Kind() != reflect.Interface {
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return v
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}
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if v.IsNil() {
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return reflect.Value{}
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}
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return v.Elem()
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}
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