all: Simplify the reflect usage

* Use helper funcs in hreflect package when possible.
* Use hreflect.ConvertIfPossible to handle conversions when possible.
* Move scratch.go from common/maps to common/hstore to clear cyclic import in the next step.
* Move Indirect to hreflect and reimplementing it and adusting the behavior to preserve struct pointers.
* Adjust evaluateSubElem used by where and others making the struct pointer method case slightly faster.

common/collections/append.go

@@ -16,6 +16,8 @@ package collections
 import (
 	"fmt"
 	"reflect"
+
+	"github.com/gohugoio/hugo/common/hreflect"
 )
 
 // Append appends from to a slice to and returns the resulting slice.
@@ -25,7 +27,7 @@ func Append(to any, from ...any) (any, error) {
 	if len(from) == 0 {
 		return to, nil
 	}
-	tov, toIsNil := indirect(reflect.ValueOf(to))
+	tov, toIsNil := hreflect.Indirect(reflect.ValueOf(to))
 
 	toIsNil = toIsNil || to == nil
 	var tot reflect.Type
@@ -100,7 +102,7 @@ func Append(to any, from ...any) (any, error) {
 		fv := reflect.ValueOf(f)
 		if !fv.IsValid() || !fv.Type().AssignableTo(tot) {
 			// Fall back to a []interface{} slice.
-			tov, _ := indirect(reflect.ValueOf(to))
+			tov, _ := hreflect.Indirect(reflect.ValueOf(to))
 			return appendToInterfaceSlice(tov, from...)
 		}
 		tov = reflect.Append(tov, fv)
@@ -136,17 +138,3 @@ func appendToInterfaceSlice(tov reflect.Value, from ...any) ([]any, error) {
 
 	return tos, 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
-}

common/collections/append_test.go

@@ -15,7 +15,6 @@ package collections
 
 import (
 	"html/template"
-	"reflect"
 	"testing"
 
 	qt "github.com/frankban/quicktest"
@@ -148,66 +147,3 @@ func TestAppendShouldMakeACopyOfTheInputSlice(t *testing.T) {
 	c.Assert(result, qt.DeepEquals, []string{"a", "b", "c"})
 	c.Assert(slice, qt.DeepEquals, []string{"d", "b"})
 }
-
-func TestIndirect(t *testing.T) {
-	t.Parallel()
-	c := qt.New(t)
-
-	type testStruct struct {
-		Field string
-	}
-
-	var (
-		nilPtr      *testStruct
-		nilIface    interface{} = nil
-		nonNilIface interface{} = &testStruct{Field: "hello"}
-	)
-
-	tests := []struct {
-		name     string
-		input    any
-		wantKind reflect.Kind
-		wantNil  bool
-	}{
-		{
-			name:     "nil pointer",
-			input:    nilPtr,
-			wantKind: reflect.Ptr,
-			wantNil:  true,
-		},
-		{
-			name:     "nil interface",
-			input:    nilIface,
-			wantKind: reflect.Invalid,
-			wantNil:  false,
-		},
-		{
-			name:     "non-nil pointer to struct",
-			input:    &testStruct{Field: "abc"},
-			wantKind: reflect.Struct,
-			wantNil:  false,
-		},
-		{
-			name:     "non-nil interface holding pointer",
-			input:    nonNilIface,
-			wantKind: reflect.Struct,
-			wantNil:  false,
-		},
-		{
-			name:     "plain value",
-			input:    testStruct{Field: "xyz"},
-			wantKind: reflect.Struct,
-			wantNil:  false,
-		},
-	}
-
-	for _, tt := range tests {
-		t.Run(tt.name, func(t *testing.T) {
-			v := reflect.ValueOf(tt.input)
-			got, isNil := indirect(v)
-
-			c.Assert(got.Kind(), qt.Equals, tt.wantKind)
-			c.Assert(isNil, qt.Equals, tt.wantNil)
-		})
-	}
-}

common/hreflect/convert.go

@@ -0,0 +1,222 @@
+// Copyright 2025 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 hreflect
+
+import (
+	"fmt"
+	"math"
+	"reflect"
+)
+
+var (
+	typeInt64   = reflect.TypeFor[int64]()
+	typeFloat64 = reflect.TypeFor[float64]()
+	typeString  = reflect.TypeFor[string]()
+)
+
+// ToInt64 converts v to int64 if possible, returning an error if not.
+func ToInt64E(v reflect.Value) (int64, error) {
+	if v, ok := ConvertIfPossible(v, typeInt64); ok {
+		return v.Int(), nil
+	}
+	return 0, errConvert(v, "int64")
+}
+
+// ToInt64 converts v to int64 if possible. It panics if the conversion is not possible.
+func ToInt64(v reflect.Value) int64 {
+	vv, err := ToInt64E(v)
+	if err != nil {
+		panic(err)
+	}
+	return vv
+}
+
+// ToFloat64E converts v to float64 if possible, returning an error if not.
+func ToFloat64E(v reflect.Value) (float64, error) {
+	if v, ok := ConvertIfPossible(v, typeFloat64); ok {
+		return v.Float(), nil
+	}
+	return 0, errConvert(v, "float64")
+}
+
+// ToFloat64 converts v to float64 if possible, panicking if not.
+func ToFloat64(v reflect.Value) float64 {
+	vv, err := ToFloat64E(v)
+	if err != nil {
+		panic(err)
+	}
+	return vv
+}
+
+// ToStringE converts v to string if possible, returning an error if not.
+func ToStringE(v reflect.Value) (string, error) {
+	vv, err := ToStringValueE(v)
+	if err != nil {
+		return "", err
+	}
+	return vv.String(), nil
+}
+
+func ToStringValueE(v reflect.Value) (reflect.Value, error) {
+	if v, ok := ConvertIfPossible(v, typeString); ok {
+		return v, nil
+	}
+	return reflect.Value{}, errConvert(v, "string")
+}
+
+// ToString converts v to string if possible, panicking if not.
+func ToString(v reflect.Value) string {
+	vv, err := ToStringE(v)
+	if err != nil {
+		panic(err)
+	}
+	return vv
+}
+
+func errConvert(v reflect.Value, s string) error {
+	return fmt.Errorf("unable to convert value of type %q to %q", v.Type().String(), s)
+}
+
+// ConvertIfPossible tries to convert val to typ if possible.
+// This is currently only implemented for int kinds,
+// added to handle the move to a new YAML library which produces uint64 for unsigned integers.
+// We can expand on this later if needed.
+// This conversion is lossless.
+// See Issue 14079.
+func ConvertIfPossible(val reflect.Value, typ reflect.Type) (reflect.Value, bool) {
+	switch val.Kind() {
+	case reflect.Ptr, reflect.Interface:
+		if val.IsNil() {
+			// Return typ's zero value.
+			return reflect.Zero(typ), true
+		}
+		val = val.Elem()
+	}
+
+	if val.Type().AssignableTo(typ) {
+		// No conversion needed.
+		return val, true
+	}
+
+	if IsInt(typ.Kind()) {
+		return convertToIntIfPossible(val, typ)
+	}
+	if IsFloat(typ.Kind()) {
+		return convertToFloatIfPossible(val, typ)
+	}
+	if IsUint(typ.Kind()) {
+		return convertToUintIfPossible(val, typ)
+	}
+	if IsString(typ.Kind()) && IsString(val.Kind()) {
+		return val.Convert(typ), true
+	}
+
+	return reflect.Value{}, false
+}
+
+func convertToUintIfPossible(val reflect.Value, typ reflect.Type) (reflect.Value, bool) {
+	if IsInt(val.Kind()) {
+		i := val.Int()
+		if i < 0 {
+			return reflect.Value{}, false
+		}
+		u := uint64(i)
+		if typ.OverflowUint(u) {
+			return reflect.Value{}, false
+		}
+		return reflect.ValueOf(u).Convert(typ), true
+	}
+	if IsUint(val.Kind()) {
+		if typ.OverflowUint(val.Uint()) {
+			return reflect.Value{}, false
+		}
+		return val.Convert(typ), true
+	}
+	if IsFloat(val.Kind()) {
+		f := val.Float()
+		if f < 0 || f > float64(math.MaxUint64) {
+			return reflect.Value{}, false
+		}
+		if f != math.Trunc(f) {
+			return reflect.Value{}, false
+		}
+		u := uint64(f)
+		if typ.OverflowUint(u) {
+			return reflect.Value{}, false
+		}
+		return reflect.ValueOf(u).Convert(typ), true
+	}
+	return reflect.Value{}, false
+}
+
+func convertToFloatIfPossible(val reflect.Value, typ reflect.Type) (reflect.Value, bool) {
+	if IsInt(val.Kind()) {
+		i := val.Int()
+		f := float64(i)
+		if typ.OverflowFloat(f) {
+			return reflect.Value{}, false
+		}
+		return reflect.ValueOf(f).Convert(typ), true
+	}
+	if IsUint(val.Kind()) {
+		u := val.Uint()
+		f := float64(u)
+		if typ.OverflowFloat(f) {
+			return reflect.Value{}, false
+		}
+		return reflect.ValueOf(f).Convert(typ), true
+	}
+	if IsFloat(val.Kind()) {
+		if typ.OverflowFloat(val.Float()) {
+			return reflect.Value{}, false
+		}
+		return val.Convert(typ), true
+	}
+
+	return reflect.Value{}, false
+}
+
+func convertToIntIfPossible(val reflect.Value, typ reflect.Type) (reflect.Value, bool) {
+	if IsInt(val.Kind()) {
+		if typ.OverflowInt(val.Int()) {
+			return reflect.Value{}, false
+		}
+		return val.Convert(typ), true
+	}
+	if IsUint(val.Kind()) {
+		if val.Uint() > uint64(math.MaxInt64) {
+			return reflect.Value{}, false
+		}
+		if typ.OverflowInt(int64(val.Uint())) {
+			return reflect.Value{}, false
+		}
+		return val.Convert(typ), true
+	}
+	if IsFloat(val.Kind()) {
+		f := val.Float()
+		if f < float64(math.MinInt64) || f > float64(math.MaxInt64) {
+			return reflect.Value{}, false
+		}
+		if f != math.Trunc(f) {
+			return reflect.Value{}, false
+		}
+		if typ.OverflowInt(int64(f)) {
+			return reflect.Value{}, false
+		}
+		return reflect.ValueOf(int64(f)).Convert(typ), true
+
+	}
+
+	return reflect.Value{}, false
+}