diff options
author | Bjørn Erik Pedersen <bjorn.erik.pedersen@gmail.com> | 2019-03-06 09:07:49 +0100 |
---|---|---|
committer | Bjørn Erik Pedersen <bjorn.erik.pedersen@gmail.com> | 2019-03-06 22:52:38 +0100 |
commit | 02eaddc2fbe92c26e67d9f82dd9aabecbbf2106c (patch) | |
tree | 517220ebb06a75e89d506183a621123d49ee20c6 /tpl/compare | |
parent | bdf47e8da80f87b7689badf48a6b8672c048d7e4 (diff) |
tpl/tplimpl: Fix template truth logic
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
Diffstat (limited to 'tpl/compare')
-rw-r--r-- | tpl/compare/init.go | 21 | ||||
-rw-r--r-- | tpl/compare/truth.go | 73 | ||||
-rw-r--r-- | tpl/compare/truth_test.go | 60 |
3 files changed, 154 insertions, 0 deletions
diff --git a/tpl/compare/init.go b/tpl/compare/init.go index f766ef890..619293203 100644 --- a/tpl/compare/init.go +++ b/tpl/compare/init.go @@ -71,6 +71,27 @@ func init() { [][2]string{}, ) + ns.AddMethodMapping(ctx.And, + []string{"and"}, + [][2]string{}, + ) + + ns.AddMethodMapping(ctx.Or, + []string{"or"}, + [][2]string{}, + ) + + // getif is used internally by Hugo. Do not document. + ns.AddMethodMapping(ctx.getIf, + []string{"getif"}, + [][2]string{}, + ) + + ns.AddMethodMapping(ctx.Not, + []string{"not"}, + [][2]string{}, + ) + ns.AddMethodMapping(ctx.Conditional, []string{"cond"}, [][2]string{ diff --git a/tpl/compare/truth.go b/tpl/compare/truth.go new file mode 100644 index 000000000..85ee22121 --- /dev/null +++ b/tpl/compare/truth.go @@ -0,0 +1,73 @@ +// Copyright 2019 The Hugo Authors. All rights reserved. +// The functions in this file is based on the Go source code, copyright +// The Go Authors and governed by a BSD-style license. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +// Package compare provides template functions for comparing values. +package compare + +import ( + "reflect" + + "github.com/gohugoio/hugo/common/hreflect" +) + +// Boolean logic, based on: +// https://github.com/golang/go/blob/178a2c42254166cffed1b25fb1d3c7a5727cada6/src/text/template/funcs.go#L302 + +func truth(arg reflect.Value) bool { + return hreflect.IsTruthfulValue(arg) +} + +// getIf will return the given arg if it is considered truthful, else an empty string. +func (*Namespace) getIf(arg reflect.Value) reflect.Value { + if truth(arg) { + return arg + } + return reflect.ValueOf("") +} + +// And computes the Boolean AND of its arguments, returning +// the first false argument it encounters, or the last argument. +func (*Namespace) And(arg0 reflect.Value, args ...reflect.Value) reflect.Value { + if !truth(arg0) { + return arg0 + } + for i := range args { + arg0 = args[i] + if !truth(arg0) { + break + } + } + return arg0 +} + +// Or computes the Boolean OR of its arguments, returning +// the first true argument it encounters, or the last argument. +func (*Namespace) Or(arg0 reflect.Value, args ...reflect.Value) reflect.Value { + if truth(arg0) { + return arg0 + } + for i := range args { + arg0 = args[i] + if truth(arg0) { + break + } + } + return arg0 +} + +// Not returns the Boolean negation of its argument. +func (*Namespace) Not(arg reflect.Value) bool { + return !truth(arg) +} diff --git a/tpl/compare/truth_test.go b/tpl/compare/truth_test.go new file mode 100644 index 000000000..04d897212 --- /dev/null +++ b/tpl/compare/truth_test.go @@ -0,0 +1,60 @@ +// Copyright 2019 The Hugo Authors. All rights reserved. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +package compare + +import ( + "reflect" + "testing" + "time" + + "github.com/gohugoio/hugo/common/hreflect" + "github.com/stretchr/testify/require" +) + +func TestTruth(t *testing.T) { + n := New() + + truthv, falsev := reflect.ValueOf(time.Now()), reflect.ValueOf(false) + + assertTruth := func(t *testing.T, v reflect.Value, expected bool) { + if hreflect.IsTruthfulValue(v) != expected { + t.Fatal("truth mismatch") + } + } + + t.Run("And", func(t *testing.T) { + assertTruth(t, n.And(truthv, truthv), true) + assertTruth(t, n.And(truthv, falsev), false) + + }) + + t.Run("Or", func(t *testing.T) { + assertTruth(t, n.Or(truthv, truthv), true) + assertTruth(t, n.Or(falsev, truthv, falsev), true) + assertTruth(t, n.Or(falsev, falsev), false) + }) + + t.Run("Not", func(t *testing.T) { + assert := require.New(t) + assert.True(n.Not(falsev)) + assert.False(n.Not(truthv)) + }) + + t.Run("getIf", func(t *testing.T) { + assert := require.New(t) + assertTruth(t, n.getIf(reflect.ValueOf(nil)), false) + s := reflect.ValueOf("Hugo") + assert.Equal(s, n.getIf(s)) + }) +} |