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dominiquelefevre wants to merge 4 commits into from
+75 −41
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Smaller stack for set defaults #240

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f157f6a
Have fewer indentations in Decoder.setDefaults().
dominiquelefevre Oct 26, 2025
cc6a7ee
Replace MultiError.merge() with MultiError.add() in Decoder.setDefaul…
dominiquelefevre Oct 26, 2025
2be8d48
Make MultiError.merge() and MultiError.add() non-inlineable.
dominiquelefevre Oct 26, 2025
e62223f
Uninline some more functions from Decoder.setDefaults().
dominiquelefevre Oct 26, 2025
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116 changes: 75 additions & 41 deletions decoder.go
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Original file line number Diff line number Diff line change
Expand Up @@ -119,7 +119,7 @@ func (d *Decoder) setDefaults(t reflect.Type, v reflect.Value) MultiError {
if v.Type().Kind() == reflect.Struct {
for i := 0; i < v.NumField(); i++ {
field := v.Field(i)
if field.Type().Kind() == reflect.Ptr && field.IsNil() && v.Type().Field(i).Anonymous {
if field.Kind() == reflect.Ptr && field.IsNil() && isAnonymousField(t, i) {
field.Set(reflect.New(field.Type().Elem()))
}
}
Expand All @@ -128,53 +128,64 @@ func (d *Decoder) setDefaults(t reflect.Type, v reflect.Value) MultiError {
for _, f := range struc.fields {
vCurrent := v.FieldByName(f.name)

if vCurrent.Type().Kind() == reflect.Struct && f.defaultValue == "" {
errs.merge(d.setDefaults(vCurrent.Type(), vCurrent))
} else if isPointerToStruct(vCurrent) && f.defaultValue == "" {
errs.merge(d.setDefaults(vCurrent.Elem().Type(), vCurrent.Elem()))
if f.defaultValue == "" {
if vCurrent.Type().Kind() == reflect.Struct {
errs.merge(d.setDefaults(vCurrent.Type(), vCurrent))
} else if isPointerToStruct(vCurrent) {
errs.merge(d.setDefaults(vCurrent.Elem().Type(), vCurrent.Elem()))
}
continue
}

if f.defaultValue != "" && f.isRequired {
errs.merge(MultiError{"default-" + f.name: errors.New("required fields cannot have a default value")})
} else if f.defaultValue != "" && vCurrent.IsZero() && !f.isRequired {
if f.typ.Kind() == reflect.Struct {
errs.merge(MultiError{"default-" + f.name: errors.New("default option is supported only on: bool, float variants, string, unit variants types or their corresponding pointers or slices")})
} else if f.typ.Kind() == reflect.Slice {
vals := strings.Split(f.defaultValue, "|")

// check if slice has one of the supported types for defaults
if _, ok := builtinConverters[f.typ.Elem().Kind()]; !ok {
errs.merge(MultiError{"default-" + f.name: errors.New("default option is supported only on: bool, float variants, string, unit variants types or their corresponding pointers or slices")})
continue
}
if f.isRequired {
errs.add("default-"+f.name, errRequiredFieldsCantHaveDefaults)
continue
}
if !vCurrent.IsZero() {
continue
}

defaultSlice := reflect.MakeSlice(f.typ, 0, cap(vals))
for _, val := range vals {
// this check is to handle if the wrong value is provided
convertedVal := builtinConverters[f.typ.Elem().Kind()](val)
if !convertedVal.IsValid() {
errs.merge(MultiError{"default-" + f.name: fmt.Errorf("failed setting default: %s is not compatible with field %s type", val, f.name)})
break
}
defaultSlice = reflect.Append(defaultSlice, convertedVal)
}
vCurrent.Set(defaultSlice)
} else if f.typ.Kind() == reflect.Ptr {
t1 := f.typ.Elem()
switch f.typ.Kind() {
case reflect.Struct:
errs.add("default-"+f.name, errUnsupportedDefaultFieldType)

if t1.Kind() == reflect.Struct || t1.Kind() == reflect.Slice {
errs.merge(MultiError{"default-" + f.name: errors.New("default option is supported only on: bool, float variants, string, unit variants types or their corresponding pointers or slices")})
}
case reflect.Slice:
vals := strings.Split(f.defaultValue, "|")

// check if slice has one of the supported types for defaults
if _, ok := builtinConverters[f.typ.Elem().Kind()]; !ok {
errs.add("default-"+f.name, errUnsupportedDefaultFieldType)
continue
}

defaultSlice := reflect.MakeSlice(f.typ, 0, cap(vals))
for _, val := range vals {
// this check is to handle if the wrong value is provided
if convertedVal := convertPointer(t1.Kind(), f.defaultValue); convertedVal.IsValid() {
vCurrent.Set(convertedVal)
}
} else {
// this check is to handle if the wrong value is provided
if convertedVal := builtinConverters[f.typ.Kind()](f.defaultValue); convertedVal.IsValid() {
vCurrent.Set(builtinConverters[f.typ.Kind()](f.defaultValue))
convertedVal := builtinConverters[f.typ.Elem().Kind()](val)
if !convertedVal.IsValid() {
errs.add("default-"+f.name, errIncompatibleValue(val, f))
break
}
defaultSlice = reflect.Append(defaultSlice, convertedVal)
}
vCurrent.Set(defaultSlice)

case reflect.Ptr:
t1 := f.typ.Elem()

if t1.Kind() == reflect.Struct || t1.Kind() == reflect.Slice {
errs.add("default-"+f.name, errUnsupportedDefaultFieldType)
}

// this check is to handle if the wrong value is provided
if convertedVal := convertPointer(t1.Kind(), f.defaultValue); convertedVal.IsValid() {
vCurrent.Set(convertedVal)
}

default:
// this check is to handle if the wrong value is provided
if convertedVal := builtinConverters[f.typ.Kind()](f.defaultValue); convertedVal.IsValid() {
vCurrent.Set(builtinConverters[f.typ.Kind()](f.defaultValue))
}
}
}
Expand All @@ -186,6 +197,11 @@ func isPointerToStruct(v reflect.Value) bool {
return !v.IsZero() && v.Type().Kind() == reflect.Ptr && v.Elem().Type().Kind() == reflect.Struct
}

//go:noinline
func isAnonymousField(t reflect.Type, nr int) bool {
return t.Field(nr).Anonymous
}

// checkRequired checks whether required fields are empty
//
// check type t recursively if t has struct fields.
Expand Down Expand Up @@ -546,6 +562,16 @@ type unmarshaler struct {

// Errors ---------------------------------------------------------------------

var (
errRequiredFieldsCantHaveDefaults = errors.New("required fields cannot have a default value")
errUnsupportedDefaultFieldType = errors.New("default option is supported only on: bool, float variants, string, unit variants types or their corresponding pointers or slices")
)

//go:noinline
func errIncompatibleValue(val string, f *fieldInfo) error {
return fmt.Errorf("failed setting default: %s is not compatible with field %s type", val, f.name)
}

// ConversionError stores information about a failed conversion.
type ConversionError struct {
Key string // key from the source map.
Expand Down Expand Up @@ -611,6 +637,14 @@ func (e MultiError) Error() string {
return fmt.Sprintf("%s (and %d other errors)", s, len(e)-1)
}

//go:noinline
func (e MultiError) add(key string, err error) {
if e[key] == nil {
e[key] = err
}
}

//go:noinline
func (e MultiError) merge(errors MultiError) {
for key, err := range errors {
if e[key] == nil {
Expand Down
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