field inspection

field.go

@@ -0,0 +1,195 @@
+package bind
+
+import (
+	"fmt"
+	"github.com/iancoleman/strcase"
+	"reflect"
+	"unicode"
+)
+
+func exported(name string) bool {
+	return unicode.IsUpper([]rune(name)[0])
+}
+
+func fields(t reflect.Type) []Field {
+	t = unpackType(t, pointer)
+	list := t.Kind() == reflect.Slice
+	t = unpackType(t, pointer|slice)
+	if t.Kind() != reflect.Struct {
+		return nil
+	}
+
+	var f []Field
+	for i := 0; i < t.NumField(); i++ {
+		tfi := t.Field(i)
+		if !exported(tfi.Name) && !tfi.Anonymous {
+			continue
+		}
+
+		if acceptsScalar(tfi.Type) {
+			var fi Field
+			ft := unpackType(tfi.Type, pointer|slice)
+			fi.isBool = ft.Kind() == reflect.Bool
+			fi.list = acceptsList(tfi.Type)
+			fi.name = strcase.ToKebab(tfi.Name)
+			fi.path = []string{tfi.Name}
+			f = append(f, fi)
+			continue
+		}
+
+		ffi := fields(tfi.Type)
+		if !tfi.Anonymous {
+			for i := range ffi {
+				ffi[i].name = fmt.Sprintf(
+					"%s-%s",
+					strcase.ToKebab(tfi.Name),
+					ffi[i].name,
+				)
+
+				ffi[i].path = append(
+					[]string{tfi.Name},
+					ffi[i].path...,
+				)
+			}
+		}
+
+		f = append(f, ffi...)
+	}
+
+	if list {
+		for i := range f {
+			f[i].list = true
+		}
+	}
+
+	return f
+}
+
+func fieldFromValue(name string, v reflect.Value) Field {
+	var fi Field
+	fi.name = strcase.ToKebab(name)
+	fi.path = []string{name}
+	fi.value = v.Interface()
+	fi.isBool = v.Kind() == reflect.Bool
+	return fi
+}
+
+func scalarMapFields(v reflect.Value) []Field {
+	var f []Field
+	for _, key := range v.MapKeys() {
+		value := v.MapIndex(key)
+		name := key.Interface().(string)
+		if value.Kind() == reflect.Slice {
+			for i := 0; i < value.Len(); i++ {
+				fi := fieldFromValue(name, value.Index(i))
+				fi.free = true
+				f = append(f, fi)
+			}
+		} else {
+			fi := fieldFromValue(name, value)
+			fi.free = true
+			f = append(f, fi)
+		}
+	}
+
+	return f
+}
+
+func prependFieldName(name string, f []Field) {
+	for i := range f {
+		f[i].name = fmt.Sprintf("%s-%s", strcase.ToKebab(name), f[i].name)
+		f[i].path = append([]string{name}, f[i].path...)
+	}
+}
+
+func listFieldValues(fieldName string, l reflect.Value) []Field {
+	var f []Field
+	for i := 0; i < l.Len(); i++ {
+		item := l.Index(i)
+		item = unpackValue(item, pointer|iface|anytype)
+		switch {
+		case isScalar(item.Type()):
+			f = append(f, fieldFromValue(fieldName, item))
+		case item.Kind() == reflect.Slice:
+			f = append(f, listFieldValues(fieldName, item)...)
+		case isScalarMap(item.Type()):
+			mf := fieldValues(item)
+			prependFieldName(fieldName, mf)
+			f = append(f, mf...)
+		case item.Kind() == reflect.Struct:
+			sf := fieldValues(item)
+			prependFieldName(fieldName, sf)
+			f = append(f, sf...)
+		}
+	}
+
+	return f
+}
+
+func fieldValues(v reflect.Value) []Field {
+	var f []Field
+	v = unpackValue(v, pointer|anytype|iface)
+	if v.Kind() == reflect.Slice {
+		for i := 0; i < v.Len(); i++ {
+			f = append(f, fieldValues(v.Index(i))...)
+		}
+
+		return f
+	}
+
+	t := v.Type()
+	if isScalarMap(t) {
+		return scalarMapFields(v)
+	}
+
+	if t.Kind() != reflect.Struct {
+		return nil
+	}
+
+	for i := 0; i < t.NumField(); i++ {
+		tfi := t.Field(i)
+		if !exported(tfi.Name) && !tfi.Anonymous {
+			continue
+		}
+
+		vfi := v.Field(i)
+		vfi = unpackValue(vfi, pointer|iface|anytype)
+		switch {
+		case isScalar(vfi.Type()):
+			f = append(f, fieldFromValue(tfi.Name, vfi))
+		case vfi.Kind() == reflect.Slice:
+			f = append(f, listFieldValues(tfi.Name, vfi)...)
+		case isScalarMap(vfi.Type()):
+			mf := fieldValues(vfi)
+			prependFieldName(tfi.Name, mf)
+			f = append(f, mf...)
+		case vfi.Kind() == reflect.Struct:
+			sf := fieldValues(vfi)
+			if !tfi.Anonymous {
+				prependFieldName(tfi.Name, sf)
+			}
+
+			f = append(f, sf...)
+		}
+	}
+
+	return f
+}
+
+func fieldsReflect[T any]() []Field {
+	t := reflect.TypeFor[T]()
+	if hasCircularType(nil, t) {
+		return nil
+	}
+
+	return fields(t)
+}
+
+func fieldValuesReflect(structure any) []Field {
+	v := reflect.ValueOf(structure)
+	if hasCircularReference(nil, v) {
+		return nil
+	}
+
+	return fieldValues(v)
+}

field_test.go

@@ -0,0 +1,278 @@
+package bind_test
+
+import (
+	"code.squareroundforest.org/arpio/bind"
+	"code.squareroundforest.org/arpio/notation"
+	"slices"
+	"sort"
+	"testing"
+)
+
+func TestField(t *testing.T) {
+	t.Run("fields", func(t *testing.T) {
+		type s0 struct {
+			FieldOne int
+		}
+
+		type s1 struct {
+			Foo int
+		}
+
+		type s2 struct {
+			s0
+			foo    int
+			FooBar int
+			Baz    s1
+			Qux    *s1
+			Chan   chan int
+			Que    bool
+			Hola   []int
+		}
+
+		f := bind.Fields[s2]()
+		if len(f) != 6 {
+			t.Fatal(notation.Sprintwt(f))
+		}
+
+		m := make(map[string]bind.Field)
+		for _, fi := range f {
+			m[fi.Name()] = fi
+		}
+
+		fieldOne := m["field-one"]
+		if !slices.Equal(fieldOne.Path(), []string{"FieldOne"}) {
+			t.Fatal(fieldOne.Name())
+		}
+
+		fooBar := m["foo-bar"]
+		if !slices.Equal(fooBar.Path(), []string{"FooBar"}) {
+			t.Fatal(fooBar.Name())
+		}
+
+		bazFoo := m["baz-foo"]
+		if !slices.Equal(bazFoo.Path(), []string{"Baz", "Foo"}) {
+			t.Fatal(bazFoo.Name())
+		}
+
+		quxFoo := m["qux-foo"]
+		if !slices.Equal(quxFoo.Path(), []string{"Qux", "Foo"}) {
+			t.Fatal(quxFoo.Name())
+		}
+
+		que := m["que"]
+		if !slices.Equal(que.Path(), []string{"Que"}) || !que.Bool() {
+			t.Fatal(que.Name())
+		}
+
+		hola := m["hola"]
+		if !slices.Equal(hola.Path(), []string{"Hola"}) || !hola.List() {
+			t.Fatal(hola.Name())
+		}
+
+		t.Run("cannot have fields", func(t *testing.T) {
+			type i []int
+			f := bind.Fields[i]()
+			if len(f) != 0 {
+				t.Fatal()
+			}
+		})
+
+		t.Run("has circular type", func(t *testing.T) {
+			type s struct{ Foo *s }
+			if len(bind.Fields[s]()) != 0 {
+				t.Fatal()
+			}
+		})
+
+		t.Run("list", func(t *testing.T) {
+			type s struct{ Foo int }
+			f := bind.Fields[[]s]()
+			if len(f) != 1 || !f[0].List() {
+				t.Fatal()
+			}
+		})
+	})
+
+	t.Run("field values", func(t *testing.T) {
+		t.Run("has circular reference", func(t *testing.T) {
+			type s struct{ Foo any }
+			var v s
+			v.Foo = v
+			if len(bind.FieldValues(v)) != 0 {
+				t.Fatal()
+			}
+		})
+
+		t.Run("slice", func(t *testing.T) {
+			type s struct{ Foo int }
+			f := bind.FieldValues([]s{{21}, {42}})
+			if len(f) != 2 || f[0].Value() != 21 || f[1].Value() != 42 {
+				t.Fatal()
+			}
+		})
+
+		t.Run("scalar map", func(t *testing.T) {
+			f := bind.FieldValues(map[string]int{"foo": 21, "bar": 42})
+			sort.Slice(f, func(i, j int) bool {
+				if f[i].Name() > f[j].Name() {
+					return true
+				}
+
+				if f[i].Value().(int) < f[j].Value().(int) {
+					return true
+				}
+
+				return false
+			})
+
+			if len(f) != 2 ||
+				f[0].Name() != "foo" || f[0].Value() != 21 || !f[0].Free() ||
+				f[1].Name() != "bar" || f[1].Value() != 42 || !f[1].Free() {
+				t.Fatal(notation.Println(f))
+			}
+		})
+
+		t.Run("scalar map with list values", func(t *testing.T) {
+			f := bind.FieldValues(map[string][]int{"foo": []int{21, 36}, "bar": []int{42, 72}})
+			sort.Slice(f, func(i, j int) bool {
+				if f[i].Name() > f[j].Name() {
+					return true
+				}
+
+				if f[i].Value().(int) < f[j].Value().(int) {
+					return true
+				}
+
+				return false
+			})
+
+			if len(f) != 4 ||
+				f[0].Name() != "foo" || f[0].Value() != 21 || !f[0].Free() ||
+				f[1].Name() != "foo" || f[1].Value() != 36 || !f[1].Free() ||
+				f[2].Name() != "bar" || f[2].Value() != 42 || !f[2].Free() ||
+				f[3].Name() != "bar" || f[3].Value() != 72 || !f[3].Free() {
+				t.Fatal(notation.Println(f))
+			}
+		})
+
+		t.Run("not a struct", func(t *testing.T) {
+			v := []int{21, 42, 84}
+			f := bind.FieldValues(v)
+			if len(f) != 0 {
+				t.Fatal()
+			}
+		})
+
+		t.Run("not exported field", func(t *testing.T) {
+			type s struct {
+				Foo int
+				bar string
+			}
+			v := s{Foo: 42, bar: "baz"}
+			f := bind.FieldValues(v)
+			if len(f) != 1 || f[0].Name() != "foo" {
+				t.Fatal()
+			}
+		})
+
+		t.Run("scalar fields", func(t *testing.T) {
+			type s struct {
+				Foo int
+				Bar bool
+			}
+			v := s{Foo: 42, Bar: true}
+			f := bind.FieldValues(v)
+			if len(f) != 2 ||
+				f[0].Name() != "foo" || !slices.Equal(f[0].Path(), []string{"Foo"}) || f[0].Value() != 42 || f[0].Bool() ||
+				f[1].Name() != "bar" || !slices.Equal(f[1].Path(), []string{"Bar"}) || f[1].Value() != true || !f[1.].Bool() {
+				t.Fatal()
+			}
+		})
+
+		t.Run("list field", func(t *testing.T) {
+			type s struct{ Foo []int }
+			v := s{Foo: []int{21, 42, 84}}
+			f := bind.FieldValues(v)
+			if len(f) != 3 ||
+				f[0].Name() != "foo" || f[0].Value() != 21 ||
+				f[1].Name() != "foo" || f[1].Value() != 42 ||
+				f[2].Name() != "foo" || f[2].Value() != 84 {
+				t.Fatal(notation.Sprintwt(f))
+			}
+		})
+
+		t.Run("list of lists", func(t *testing.T) {
+			type s struct{ Foo [][]int }
+			v := s{Foo: [][]int{{21}, {42}}}
+			f := bind.FieldValues(v)
+			if len(f) != 2 ||
+				f[0].Name() != "foo" || f[0].Value() != 21 ||
+				f[1].Name() != "foo" || f[1].Value() != 42 {
+				t.Fatal()
+			}
+		})
+
+		t.Run("list of scalar maps", func(t *testing.T) {
+			type s struct{ Foo any }
+			v := s{Foo: []any{map[string]int{"foo": 42}}}
+			f := bind.FieldValues(v)
+			if len(f) != 1 || f[0].Name() != "foo-foo" || f[0].Value() != 42 {
+				t.Fatal(notation.Sprintwt(f))
+			}
+		})
+
+		t.Run("list of structs", func(t *testing.T) {
+			type s struct{ Foo any }
+			v := s{Foo: []any{s{Foo: 21}, s{Foo: 42}}}
+			f := bind.FieldValues(v)
+			if len(f) != 2 ||
+				f[0].Name() != "foo-foo" || f[0].Value() != 21 ||
+				f[1].Name() != "foo-foo" || f[1].Value() != 42 {
+				t.Fatal()
+			}
+		})
+
+		t.Run("scalar map field", func(t *testing.T) {
+			type s struct{ Foo map[string]int }
+			v := s{Foo: map[string]int{"foo": 42}}
+			f := bind.FieldValues(v)
+			if len(f) != 1 || f[0].Name() != "foo-foo" || f[0].Value() != 42 {
+				t.Fatal()
+			}
+		})
+
+		t.Run("anonymous field", func(t *testing.T) {
+			type s0 struct{ Foo int }
+			type s1 struct {
+				s0
+				Bar int
+			}
+			var v s1
+			v.Foo = 21
+			v.Bar = 42
+			f := bind.FieldValues(v)
+			if len(f) != 2 ||
+				f[0].Name() != "foo" || f[0].Value() != 21 ||
+				f[1].Name() != "bar" || f[1].Value() != 42 {
+				t.Fatal()
+			}
+		})
+
+		t.Run("child struct", func(t *testing.T) {
+			type S0 struct{ Foo int }
+			type s1 struct {
+				S0  S0
+				Bar int
+			}
+			var v s1
+			v.S0.Foo = 21
+			v.Bar = 42
+			f := bind.FieldValues(v)
+			if len(f) != 2 ||
+				f[0].Name() != "s-0-foo" || f[0].Value() != 21 ||
+				f[1].Name() != "bar" || f[1].Value() != 42 {
+				t.Fatal(notation.Sprintwt(f))
+			}
+		})
+	})
+}

go.mod

@@ -1,3 +1,8 @@
 module code.squareroundforest.org/arpio/bind
 
 go 1.25.0
+
+require (
+	code.squareroundforest.org/arpio/notation v0.0.0-20250826181910-5140794b16b2 // indirect
+	github.com/iancoleman/strcase v0.3.0 // indirect
+)

go.sum

@@ -0,0 +1,4 @@
+code.squareroundforest.org/arpio/notation v0.0.0-20250826181910-5140794b16b2 h1:S4mjQHL70CuzFg1AGkr0o0d+4M+ZWM0sbnlYq6f0b3I=
+code.squareroundforest.org/arpio/notation v0.0.0-20250826181910-5140794b16b2/go.mod h1:ait4Fvg9o0+bq5hlxi9dAcPL5a+/sr33qsZPNpToMLY=
+github.com/iancoleman/strcase v0.3.0 h1:nTXanmYxhfFAMjZL34Ov6gkzEsSJZ5DbhxWjvSASxEI=
+github.com/iancoleman/strcase v0.3.0/go.mod h1:iwCmte+B7n89clKwxIoIXy/HfoL7AsD47ZCWhYzw7ho=

lib.go

@@ -1,10 +1,15 @@
 // provides more flexible and permissive ways of setting values than reflect.Value.Set
+// circular type structures not supported
+// it handles scalar fields
+// primary use cases by design are: command line options, environment variables, ini file fields, URL query parameters, HTTP form values
 package bind
 
 type Field struct {
 	name   string
 	path   []string
+	isBool bool
 	list   bool
+	free   bool
 	value  any
 }
 
@@ -33,14 +38,16 @@ func (f Field) Path() []string {
 
 func (f Field) Name() string { return f.name }
 func (f Field) List() bool   { return f.list }
+func (f Field) Bool() bool   { return f.isBool }
+func (f Field) Free() bool   { return f.free }
 func (f Field) Value() any   { return f.value }
 
 func Fields[T any]() []Field {
-	return nil
+	return fieldsReflect[T]()
 }
 
 func FieldValues(structure any) []Field {
-	return nil
+	return fieldValuesReflect(structure)
 }
 
 func BindFields(structure any, values []Field) []Field {

notes.txt

@@ -0,0 +1,3 @@
+maps with string keys and scalar, or list of scalar, values can be supported
+fields being set by name, can be converted first to use path
+add time and duration support. Can there be any other important quasi-scalars?

scalar.go

@@ -64,14 +64,38 @@ func bindScalarCreate(t reflect.Type, values []any) (reflect.Value, bool) {
 }
 
 func bindScalarReflect(receiver any, values []any) bool {
-	return bindScalar(reflect.ValueOf(receiver), values)
+	v := reflect.ValueOf(receiver)
+	if hasCircularReference(nil, v) {
+		return false
+	}
+
+	for _, vi := range values {
+		if hasCircularReference(nil, reflect.ValueOf(vi)) {
+			return false
+		}
+	}
+
+	return bindScalar(v, values)
 }
 
 func bindScalarCreateReflect[T any](values []any) (T, bool) {
-	v, ok := bindScalarCreate(reflect.TypeFor[T](), values)
+	t := reflect.TypeFor[T]()
+	if hasCircularType(nil, t) {
+		var tt T
+		return tt, false
+	}
+
+	for _, vi := range values {
+		if hasCircularReference(nil, reflect.ValueOf(vi)) {
+			var tt T
+			return tt, false
+		}
+	}
+
+	v, ok := bindScalarCreate(t, values)
 	if !ok {
-		var v T
+		var tt T
-		return v, false
+		return tt, false
 	}
 
 	return v.Interface().(T), true

scalar_test.go

@@ -146,6 +146,16 @@ func TestScalar(t *testing.T) {
 				t.Fatal()
 			}
 		})
+
+		t.Run("value has circular reference", func(t *testing.T) {
+			var r any
+			var v any
+			p := &v
+			*p = p
+			if bind.BindScalar(&r, p) {
+				t.Fatal()
+			}
+		})
 	})
 
 	t.Run("bind scalar with create", func(t *testing.T) {
@@ -202,5 +212,21 @@ func TestScalar(t *testing.T) {
 				t.Fatal()
 			}
 		})
+
+		t.Run("receiver has circular type", func(t *testing.T) {
+			type s []s
+			if _, ok := bind.BindScalarCreate[s]("foo"); ok {
+				t.Fatal()
+			}
+		})
+	
+		t.Run("value has circular reference", func(t *testing.T) {
+			var v any
+			p := &v
+			*p = p
+			if _, ok := bind.BindScalarCreate[any](p); ok {
+				t.Fatal()
+			}
+		})
 	})
 }

scan.go

@@ -69,6 +69,7 @@ func scanString(t reflect.Type, s string) (any, bool) {
 }
 
 func scan(t reflect.Type, v any) (any, bool) {
+	// time and duration support
 	if vv, ok := scanConvert(t, v); ok {
 		return vv, true
 	}

scan_test.go

@@ -1,8 +1,8 @@
 package bind_test
 
 import (
-	"testing"
 	"code.squareroundforest.org/arpio/bind"
+	"testing"
 )
 
 func TestScan(t *testing.T) {

struct.go

@@ -1 +0,0 @@
-package bind

type.go

@@ -15,6 +15,86 @@ func (f unpackFlag) has(v unpackFlag) bool {
 	return f&v > 0
 }
 
+func setVisited[T comparable](visited map[T]bool, k T) map[T]bool {
+	s := make(map[T]bool)
+	for v := range visited {
+		s[v] = true
+	}
+
+	s[k] = true
+	return s
+}
+
+func hasCircularType(visited map[reflect.Type]bool, t reflect.Type) bool {
+	if visited[t] {
+		return true
+	}
+
+	switch t.Kind() {
+	case reflect.Pointer, reflect.Slice:
+		visited = setVisited(visited, t)
+		return hasCircularType(visited, t.Elem())
+	case reflect.Struct:
+		visited = setVisited(visited, t)
+		for i := 0; i < t.NumField(); i++ {
+			if hasCircularType(visited, t.Field(i).Type) {
+				return true
+			}
+		}
+
+		return false
+	default:
+		return false
+	}
+}
+
+func hasCircularReference(visited map[uintptr]bool, v reflect.Value) bool {
+	if hasCircularType(nil, v.Type()) {
+		return true
+	}
+
+	switch v.Kind() {
+	case reflect.Pointer:
+		p := v.Pointer()
+		if visited[p] {
+			return true
+		}
+
+		visited = setVisited(visited, v.Pointer())
+		return hasCircularReference(visited, v.Elem())
+	case reflect.Slice:
+		p := v.Pointer()
+		if visited[p] {
+			return true
+		}
+
+		visited = setVisited(visited, v.Pointer())
+		for i := 0; i < v.Len(); i++ {
+			if hasCircularReference(visited, v.Index(i)) {
+				return true
+			}
+		}
+
+		return false
+	case reflect.Interface:
+		if v.IsNil() {
+			return false
+		}
+
+		return hasCircularReference(visited, v.Elem())
+	case reflect.Struct:
+		for i := 0; i < v.NumField(); i++ {
+			if hasCircularReference(visited, v.Field(i)) {
+				return true
+			}
+		}
+
+		return false
+	}
+
+	return false
+}
+
 func isAny(t reflect.Type) bool {
 	return t.Kind() == reflect.Interface && t.NumMethod() == 0
 }
@@ -115,20 +195,52 @@ func bindable(t reflect.Type) bool {
 	return acceptsScalar(t) || acceptsFields(t)
 }
 
+func acceptsScalarChecked(t reflect.Type) bool {
+	if hasCircularType(nil, t) {
+		return false
+	}
+
+	return acceptsScalar(t)
+}
+
+func acceptsFieldsChecked(t reflect.Type) bool {
+	if hasCircularType(nil, t) {
+		return false
+	}
+
+	return acceptsFields(t)
+}
+
+func acceptsListChecked(t reflect.Type) bool {
+	if hasCircularType(nil, t) {
+		return false
+	}
+
+	return acceptsList(t)
+}
+
+func bindableChecked(t reflect.Type) bool {
+	if hasCircularType(nil, t) {
+		return false
+	}
+
+	return bindable(t)
+}
+
 func acceptsScalarReflect[T any]() bool {
-	return acceptsScalar(reflect.TypeFor[T]())
+	return acceptsScalarChecked(reflect.TypeFor[T]())
 }
 
 func acceptsFieldsReflect[T any]() bool {
-	return acceptsFields(reflect.TypeFor[T]())
+	return acceptsFieldsChecked(reflect.TypeFor[T]())
 }
 
 func acceptsListReflect[T any]() bool {
-	return acceptsList(reflect.TypeFor[T]())
+	return acceptsListChecked(reflect.TypeFor[T]())
 }
 
 func bindableReflect[T any]() bool {
-	return bindable(reflect.TypeFor[T]())
+	return bindableChecked(reflect.TypeFor[T]())
 }
 
 // expected to be called with types that can pass the bindable check

type_test.go

@@ -275,4 +275,94 @@ func TestTypeChecks(t *testing.T) {
 			}
 		})
 	})
+
+	t.Run("circular type", func(t *testing.T) {
+		t.Run("via pointer", func(t *testing.T) {
+			type p *p
+			if bind.Bindable[p]() {
+				t.Fatal()
+			}
+		})
+
+		t.Run("via slice", func(t *testing.T) {
+			type s []s
+			if bind.Bindable[s]() {
+				t.Fatal()
+			}
+		})
+
+		t.Run("pointer via struct field", func(t *testing.T) {
+			type s struct{ f *s }
+			if bind.Bindable[s]() {
+				t.Fatal()
+			}
+		})
+
+		t.Run("slice via struct field", func(t *testing.T) {
+			type s struct{ f []s }
+			if bind.Bindable[s]() {
+				t.Fatal()
+			}
+		})
+	})
+
+	t.Run("circular reference", func(t *testing.T) {
+		t.Run("via pointer", func(t *testing.T) {
+			p := new(any)
+			*p = p
+			if bind.BindScalar(p, "42") {
+				t.Fatal()
+			}
+		})
+
+		t.Run("via slice", func(t *testing.T) {
+			s := make([]any, 1)
+			s[0] = s
+			if bind.BindScalar(s, "42") {
+				t.Fatal()
+			}
+		})
+
+		t.Run("via interface and pointer", func(t *testing.T) {
+			var v any
+			v = &v
+			if bind.BindScalar(v, "42") {
+				t.Fatal()
+			}
+		})
+
+		t.Run("via struct field and pointer", func(t *testing.T) {
+			type s struct{ F *s }
+			var v s
+			v.F = &v
+			if len(bind.FieldValues(v)) > 0 {
+				t.Fatal()
+			}
+		})
+
+		t.Run("via struct field and slice", func(t *testing.T) {
+			type s struct{ F []s }
+			var v s
+			v.F = []s{v}
+			if len(bind.FieldValues(v)) > 0 {
+				t.Fatal()
+			}
+		})
+
+		t.Run("via struct field and interface", func(t *testing.T) {
+			var s struct{ F any }
+			s.F = s
+			if len(bind.FieldValues(s)) > 0 {
+				t.Fatal()
+			}
+		})
+
+		t.Run("value with circular type", func(t *testing.T) {
+			type p *p
+			var v p
+			if len(bind.FieldValues(v)) > 0 {
+				t.Fatal()
+			}
+		})
+	})
 }