Skip to content
Permalink
Browse files

tpl/collections: Add Merge function

Merges two maps recursively and returns a new one. Merge is case-insensitive.

Fixes #5992
  • Loading branch information...
bep committed Jul 11, 2019
1 parent 020086c commit c624a77992c4f7c1bcb5f659e89332d8588986b7
Showing with 281 additions and 0 deletions.
  1. +10 −0 tpl/collections/init.go
  2. +98 −0 tpl/collections/merge.go
  3. +173 −0 tpl/collections/merge_test.go
@@ -183,6 +183,16 @@ func init() {
},
)

ns.AddMethodMapping(ctx.Merge,
[]string{"merge"},
[][2]string{
{`{{ dict "title" "Hugo Rocks!" | collections.Merge (dict "title" "Default Title" "description" "Yes, Hugo Rocks!") | sort }}`,
`[Yes, Hugo Rocks! Hugo Rocks!]`},
{`{{ merge (dict "title" "Default Title" "description" "Yes, Hugo Rocks!") (dict "title" "Hugo Rocks!") | sort }}`,
`[Yes, Hugo Rocks! Hugo Rocks!]`},
},
)

return ns

}
@@ -0,0 +1,98 @@
// 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 collections

import (
"reflect"
"strings"

"github.com/gohugoio/hugo/common/hreflect"

"github.com/pkg/errors"
)

// Merge creates a copy of dst and merges src into it.
// Currently only maps supported. Key handling is case insensitive.
func (ns *Namespace) Merge(src, dst interface{}) (interface{}, error) {

vdst, vsrc := reflect.ValueOf(dst), reflect.ValueOf(src)

if vdst.Kind() != reflect.Map {
return nil, errors.Errorf("destination must be a map, got %T", dst)
}

if !hreflect.IsTruthfulValue(vsrc) {
return dst, nil
}

if vsrc.Kind() != reflect.Map {
return nil, errors.Errorf("source must be a map, got %T", src)
}

if vsrc.Type() != vdst.Type() {
return nil, errors.Errorf("incompatible map types, got %T to %T", src, dst)
}

return mergeMap(vdst, vsrc).Interface(), nil
}

func caseInsensitiveLookup(m, k reflect.Value) (reflect.Value, bool) {
if m.Type().Key().Kind() != reflect.String || k.Kind() != reflect.String {
// Fall back to direct lookup.
v := m.MapIndex(k)
return v, hreflect.IsTruthfulValue(v)
}

for _, key := range m.MapKeys() {
if strings.EqualFold(k.String(), key.String()) {
return m.MapIndex(key), true
}

}

return reflect.Value{}, false
}

func mergeMap(dst, src reflect.Value) reflect.Value {

out := reflect.MakeMap(dst.Type())

// Copy the destination map.
for _, key := range dst.MapKeys() {
v := dst.MapIndex(key)
out.SetMapIndex(key, v)
}

// Add all keys in src not already in destination.
// Maps of the same type will be merged.
for _, key := range src.MapKeys() {
sv := src.MapIndex(key)
dv, found := caseInsensitiveLookup(dst, key)

if found {
// If both are the same map type, merge.
dve := dv.Elem()
if dve.Kind() == reflect.Map {
sve := sv.Elem()
if dve.Type() == sve.Type() {
out.SetMapIndex(key, mergeMap(dve, sve))
}
}
} else {
out.SetMapIndex(key, sv)
}
}

return out
}
@@ -0,0 +1,173 @@
// 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 collections

import (
"bytes"
"fmt"
"reflect"
"runtime"
"strings"
"testing"

"github.com/gohugoio/hugo/parser"

"github.com/gohugoio/hugo/parser/metadecoders"

"github.com/gohugoio/hugo/deps"
"github.com/stretchr/testify/require"
)

func TestMerge(t *testing.T) {

ns := New(&deps.Deps{})

simpleMap := map[string]interface{}{"a": 1, "b": 2}

for i, test := range []struct {
name string
dst interface{}
src interface{}
expect interface{}
isErr bool
}{
{
"basic",
map[string]interface{}{"a": 1, "b": 2},
map[string]interface{}{"a": 42, "c": 3},
map[string]interface{}{"a": 1, "b": 2, "c": 3}, false},
{
"basic case insensitive",
map[string]interface{}{"a": 1, "b": 2},
map[string]interface{}{"A": 42, "c": 3},
map[string]interface{}{"a": 1, "b": 2, "c": 3}, false},
{
"nested",
map[string]interface{}{"a": 1, "b": map[string]interface{}{"d": 1, "e": 2}},
map[string]interface{}{"a": 42, "c": 3, "b": map[string]interface{}{"d": 55, "e": 66, "f": 3}},
map[string]interface{}{"a": 1, "b": map[string]interface{}{"d": 1, "e": 2, "f": 3}, "c": 3}, false},
{"src nil", simpleMap, nil, simpleMap, false},
// Error cases.
{"dst not a map", "not a map", nil, nil, true},
{"src not a map", simpleMap, "not a map", nil, true},
{"diferent map typs", simpleMap, map[int]interface{}{32: "a"}, nil, true},
{"all nil", nil, nil, nil, true},
} {

test := test

t.Run(test.name, func(t *testing.T) {
t.Parallel()
errMsg := fmt.Sprintf("[%d] %v", i, test)

assert := require.New(t)

srcStr, dstStr := fmt.Sprint(test.src), fmt.Sprint(test.dst)

result, err := ns.Merge(test.src, test.dst)

if test.isErr {
assert.Error(err, errMsg)
return
}

assert.NoError(err, errMsg)
assert.Equal(test.expect, result, errMsg)

// map sort in fmt was fixed in go 1.12.
if !strings.HasPrefix(runtime.Version(), "go1.11") {
// Verify that the original maps are preserved.
assert.Equal(srcStr, fmt.Sprint(test.src))
assert.Equal(dstStr, fmt.Sprint(test.dst))
}

})
}
}

func TestMergeDataFormats(t *testing.T) {
assert := require.New(t)
ns := New(&deps.Deps{})

toml1 := `
V1 = "v1_1"
[V2s]
V21 = "v21_1"
`

toml2 := `
V1 = "v1_2"
V2 = "v2_2"
[V2s]
V21 = "v21_2"
V22 = "v22_2"
`

meta1, err := metadecoders.Default.UnmarshalToMap([]byte(toml1), metadecoders.TOML)
assert.NoError(err)
meta2, err := metadecoders.Default.UnmarshalToMap([]byte(toml2), metadecoders.TOML)
assert.NoError(err)

for _, format := range []metadecoders.Format{metadecoders.JSON, metadecoders.YAML, metadecoders.TOML} {

var dataStr1, dataStr2 bytes.Buffer
err = parser.InterfaceToConfig(meta1, format, &dataStr1)
assert.NoError(err)
err = parser.InterfaceToConfig(meta2, format, &dataStr2)
assert.NoError(err)

dst, err := metadecoders.Default.UnmarshalToMap(dataStr1.Bytes(), format)
assert.NoError(err)
src, err := metadecoders.Default.UnmarshalToMap(dataStr2.Bytes(), format)
assert.NoError(err)

merged, err := ns.Merge(src, dst)
assert.NoError(err)

assert.Equal(map[string]interface{}{"V1": "v1_1", "V2": "v2_2", "V2s": map[string]interface{}{"V21": "v21_1", "V22": "v22_2"}}, merged)
}

}

func TestCaseInsensitiveMapLookup(t *testing.T) {
assert := require.New(t)

m1 := reflect.ValueOf(map[string]interface{}{
"a": 1,
"B": 2,
})

m2 := reflect.ValueOf(map[int]interface{}{
1: 1,
2: 2,
})

var found bool

a, found := caseInsensitiveLookup(m1, reflect.ValueOf("A"))
assert.True(found)
assert.Equal(1, a.Interface())

b, found := caseInsensitiveLookup(m1, reflect.ValueOf("b"))
assert.True(found)
assert.Equal(2, b.Interface())

two, found := caseInsensitiveLookup(m2, reflect.ValueOf(2))
assert.True(found)
assert.Equal(2, two.Interface())
}

0 comments on commit c624a77

Please sign in to comment.
You can’t perform that action at this time.