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common/maps: Improve append in Scratch

This commit consolidates the reflective collections handling in `.Scratch` vs the `tpl` package so they use the same code paths.

This commit also adds support for a corner case where a typed slice is appended to a nil or empty `[]interface{}`.

Fixes #5275
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bep committed Oct 8, 2018
1 parent e2201ef commit 23f48c300cb5ffe0fe43c88464f38c68831a17ad
@@ -0,0 +1,83 @@
// Copyright 2018 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 collections
import (
"fmt"
"reflect"
)
// Append appends from to a slice to and returns the resulting slice.
// If lenght of from is one and the only element is a slice of same type as to,
// it will be appended.
func Append(to interface{}, from ...interface{}) (interface{}, error) {
tov, toIsNil := indirect(reflect.ValueOf(to))
toIsNil = toIsNil || to == nil
var tot reflect.Type
if !toIsNil {
if tov.Kind() != reflect.Slice {
return nil, fmt.Errorf("expected a slice, got %T", to)
}
tot = tov.Type().Elem()
toIsNil = tov.Len() == 0
if len(from) == 1 {
fromv := reflect.ValueOf(from[0])
if fromv.Kind() == reflect.Slice {
if toIsNil {
// If we get nil []string, we just return the []string
return from[0], nil
}
fromt := reflect.TypeOf(from[0]).Elem()
// If we get []string []string, we append the from slice to to
if tot == fromt {
return reflect.AppendSlice(tov, fromv).Interface(), nil
}
}
}
}
if toIsNil {
return Slice(from...), nil
}
for _, f := range from {
fv := reflect.ValueOf(f)
if tot != fv.Type() {
return nil, fmt.Errorf("append element type mismatch: expected %v, got %v", tot, fv.Type())
}
tov = reflect.Append(tov, fv)
}
return tov.Interface(), nil
}
// indirect is borrowed from the Go stdlib: 'text/template/exec.go'
// TODO(bep) consolidate
func indirect(v reflect.Value) (rv reflect.Value, isNil bool) {
for ; v.Kind() == reflect.Ptr || v.Kind() == reflect.Interface; v = v.Elem() {
if v.IsNil() {
return v, true
}
if v.Kind() == reflect.Interface && v.NumMethod() > 0 {
break
}
}
return v, false
}
@@ -0,0 +1,70 @@
// Copyright 2018 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 collections
import (
"fmt"
"reflect"
"testing"
"github.com/stretchr/testify/require"
)
func TestAppend(t *testing.T) {
t.Parallel()
for i, test := range []struct {
start interface{}
addend []interface{}
expected interface{}
}{
{[]string{"a", "b"}, []interface{}{"c"}, []string{"a", "b", "c"}},
{[]string{"a", "b"}, []interface{}{"c", "d", "e"}, []string{"a", "b", "c", "d", "e"}},
{[]string{"a", "b"}, []interface{}{[]string{"c", "d", "e"}}, []string{"a", "b", "c", "d", "e"}},
{nil, []interface{}{"a", "b"}, []string{"a", "b"}},
{nil, []interface{}{nil}, []interface{}{nil}},
{[]interface{}{}, []interface{}{[]string{"c", "d", "e"}}, []string{"c", "d", "e"}},
{tstSlicers{&tstSlicer{"a"}, &tstSlicer{"b"}},
[]interface{}{&tstSlicer{"c"}},
tstSlicers{&tstSlicer{"a"}, &tstSlicer{"b"}, &tstSlicer{"c"}}},
{&tstSlicers{&tstSlicer{"a"}, &tstSlicer{"b"}},
[]interface{}{&tstSlicer{"c"}},
tstSlicers{&tstSlicer{"a"},
&tstSlicer{"b"},
&tstSlicer{"c"}}},
// Errors
{"", []interface{}{[]string{"a", "b"}}, false},
// No string concatenation.
{"ab",
[]interface{}{"c"},
false},
} {
errMsg := fmt.Sprintf("[%d]", i)
result, err := Append(test.start, test.addend...)
if b, ok := test.expected.(bool); ok && !b {
require.Error(t, err, errMsg)
continue
}
require.NoError(t, err, errMsg)
if !reflect.DeepEqual(test.expected, result) {
t.Fatalf("%s got\n%T: %v\nexpected\n%T: %v", errMsg, result, result, test.expected, test.expected)
}
}
}
@@ -19,10 +19,3 @@ package collections
type Grouper interface {
Group(key interface{}, items interface{}) (interface{}, error)
}
// Slicer definse a very generic way to create a typed slice. This is used
// in collections.Slice template func to get types such as Pages, PageGroups etc.
// instead of the less useful []interface{}.
type Slicer interface {
Slice(items interface{}) (interface{}, error)
}
@@ -0,0 +1,66 @@
// Copyright 2018 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 collections
import (
"reflect"
)
// Slicer definse a very generic way to create a typed slice. This is used
// in collections.Slice template func to get types such as Pages, PageGroups etc.
// instead of the less useful []interface{}.
type Slicer interface {
Slice(items interface{}) (interface{}, error)
}
// Slice returns a slice of all passed arguments.
func Slice(args ...interface{}) interface{} {
if len(args) == 0 {
return args
}
first := args[0]
firstType := reflect.TypeOf(first)
if firstType == nil {
return args
}
if g, ok := first.(Slicer); ok {
v, err := g.Slice(args)
if err == nil {
return v
}
// If Slice fails, the items are not of the same type and
// []interface{} is the best we can do.
return args
}
if len(args) > 1 {
// This can be a mix of types.
for i := 1; i < len(args); i++ {
if firstType != reflect.TypeOf(args[i]) {
// []interface{} is the best we can do
return args
}
}
}
slice := reflect.MakeSlice(reflect.SliceOf(firstType), len(args), len(args))
for i, arg := range args {
slice.Index(i).Set(reflect.ValueOf(arg))
}
return slice.Interface()
}
@@ -0,0 +1,125 @@
// Copyright 2018 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 collections
import (
"errors"
"fmt"
"testing"
"github.com/alecthomas/assert"
)
var _ Slicer = (*tstSlicer)(nil)
var _ Slicer = (*tstSlicerIn1)(nil)
var _ Slicer = (*tstSlicerIn2)(nil)
var _ testSlicerInterface = (*tstSlicerIn1)(nil)
var _ testSlicerInterface = (*tstSlicerIn1)(nil)
type testSlicerInterface interface {
Name() string
}
type testSlicerInterfaces []testSlicerInterface
type tstSlicerIn1 struct {
name string
}
type tstSlicerIn2 struct {
name string
}
type tstSlicer struct {
name string
}
func (p *tstSlicerIn1) Slice(in interface{}) (interface{}, error) {
items := in.([]interface{})
result := make(testSlicerInterfaces, len(items))
for i, v := range items {
switch vv := v.(type) {
case testSlicerInterface:
result[i] = vv
default:
return nil, errors.New("invalid type")
}
}
return result, nil
}
func (p *tstSlicerIn2) Slice(in interface{}) (interface{}, error) {
items := in.([]interface{})
result := make(testSlicerInterfaces, len(items))
for i, v := range items {
switch vv := v.(type) {
case testSlicerInterface:
result[i] = vv
default:
return nil, errors.New("invalid type")
}
}
return result, nil
}
func (p *tstSlicerIn1) Name() string {
return p.Name()
}
func (p *tstSlicerIn2) Name() string {
return p.Name()
}
func (p *tstSlicer) Slice(in interface{}) (interface{}, error) {
items := in.([]interface{})
result := make(tstSlicers, len(items))
for i, v := range items {
switch vv := v.(type) {
case *tstSlicer:
result[i] = vv
default:
return nil, errors.New("invalid type")
}
}
return result, nil
}
type tstSlicers []*tstSlicer
func TestSlice(t *testing.T) {
t.Parallel()
for i, test := range []struct {
args []interface{}
expected interface{}
}{
{[]interface{}{"a", "b"}, []string{"a", "b"}},
{[]interface{}{&tstSlicer{"a"}, &tstSlicer{"b"}}, tstSlicers{&tstSlicer{"a"}, &tstSlicer{"b"}}},
{[]interface{}{&tstSlicer{"a"}, "b"}, []interface{}{&tstSlicer{"a"}, "b"}},
{[]interface{}{}, []interface{}{}},
{[]interface{}{nil}, []interface{}{nil}},
{[]interface{}{5, "b"}, []interface{}{5, "b"}},
{[]interface{}{&tstSlicerIn1{"a"}, &tstSlicerIn2{"b"}}, testSlicerInterfaces{&tstSlicerIn1{"a"}, &tstSlicerIn2{"b"}}},
{[]interface{}{&tstSlicerIn1{"a"}, &tstSlicer{"b"}}, []interface{}{&tstSlicerIn1{"a"}, &tstSlicer{"b"}}},
} {
errMsg := fmt.Sprintf("[%d] %v", i, test.args)
result := Slice(test.args...)
assert.Equal(t, test.expected, result, errMsg)
}
assert.Len(t, Slice(), 0)
}
@@ -18,6 +18,7 @@ import (
"sort"
"sync"
"github.com/gohugoio/hugo/common/collections"
"github.com/gohugoio/hugo/common/math"
)
@@ -40,14 +41,12 @@ func (c *Scratch) Add(key string, newAddend interface{}) (string, error) {
if found {
var err error
addendV := reflect.ValueOf(existingAddend)
addendV := reflect.TypeOf(existingAddend)
if addendV.Kind() == reflect.Slice || addendV.Kind() == reflect.Array {
nav := reflect.ValueOf(newAddend)
if nav.Kind() == reflect.Slice || nav.Kind() == reflect.Array {
newVal = reflect.AppendSlice(addendV, nav).Interface()
} else {
newVal = reflect.Append(addendV, nav).Interface()
newVal, err = collections.Append(existingAddend, newAddend)
if err != nil {
return "", err
}
} else {
newVal, err = math.DoArithmetic(existingAddend, newAddend, '+')
Oops, something went wrong.

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