Function to convert Go struct back to `config.Value` (#935)

## Changes This PR is the counterpart to #904. With this change, we are able to convert a `config.Value` into a Go struct, make modifications to the Go struct, and reflect those changes in a new `config.Value`. This functionality allows us to incrementally introduce this configuration representation to existing bundle mutators. Bundle mutators expect a `*bundle.Bundle` argument and mutate its configuration directly. These mutations are not reflected in the corresponding `config.Value` (once introduced), which means we cannot use the `config.Value` as source of truth until we update _all_ mutators. To address this, we can run `convert.ToTyped` and `convert.FromTyped` at the mutator boundary (from `bundle.Apply`) and capture changes made to the Go struct. Then we can incrementally make mutators aware of the `config.Value` configuration and have them mutate that structure directly. ## Tests New unit tests pass. Manual spot checks against the bundle configuration type.
2023-11-15 10:19:51 +01:00 · 2023-11-15 10:19:51 +01:00 · 2c908f8fea
parent a25f10f247
commit 2c908f8fea
6 changed files with 810 additions and 0 deletions
--- a/libs/config/convert/end_to_end_test.go
+++ b/libs/config/convert/end_to_end_test.go
@ -0,0 +1,61 @@
+package convert
+
+import (
+	"testing"
+
+	"github.com/databricks/cli/libs/config"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func assertFromTypedToTypedEqual[T any](t *testing.T, src T) {
+	nv, err := FromTyped(src, config.NilValue)
+	require.NoError(t, err)
+
+	var dst T
+	err = ToTyped(&dst, nv)
+	require.NoError(t, err)
+	assert.Equal(t, src, dst)
+}
+
+func TestAdditional(t *testing.T) {
+	type StructType struct {
+		Str string `json:"str"`
+	}
+
+	type Tmp struct {
+		MapToPointer   map[string]*string `json:"map_to_pointer"`
+		SliceOfPointer []*string          `json:"slice_of_pointer"`
+		NestedStruct   StructType         `json:"nested_struct"`
+	}
+
+	t.Run("nil", func(t *testing.T) {
+		assertFromTypedToTypedEqual(t, Tmp{})
+	})
+
+	t.Run("empty map", func(t *testing.T) {
+		assertFromTypedToTypedEqual(t, Tmp{
+			MapToPointer: map[string]*string{},
+		})
+	})
+
+	t.Run("map with nil value", func(t *testing.T) {
+		assertFromTypedToTypedEqual(t, Tmp{
+			MapToPointer: map[string]*string{
+				"key": nil,
+			},
+		})
+	})
+
+	t.Run("empty slice", func(t *testing.T) {
+		assertFromTypedToTypedEqual(t, Tmp{
+			SliceOfPointer: []*string{},
+		})
+	})
+
+	t.Run("slice with nil value", func(t *testing.T) {
+		assertFromTypedToTypedEqual(t, Tmp{
+			SliceOfPointer: []*string{nil},
+		})
+	})
+}
--- a/libs/config/convert/from_typed.go
+++ b/libs/config/convert/from_typed.go
@ -0,0 +1,214 @@
+package convert
+
+import (
+	"fmt"
+	"reflect"
+
+	"github.com/databricks/cli/libs/config"
+)
+
+// FromTyped converts changes made in the typed structure w.r.t. the configuration value
+// back to the configuration value, retaining existing location information where possible.
+func FromTyped(src any, ref config.Value) (config.Value, error) {
+	srcv := reflect.ValueOf(src)
+
+	// Dereference pointer if necessary
+	for srcv.Kind() == reflect.Pointer {
+		if srcv.IsNil() {
+			return config.NilValue, nil
+		}
+		srcv = srcv.Elem()
+	}
+
+	switch srcv.Kind() {
+	case reflect.Struct:
+		return fromTypedStruct(srcv, ref)
+	case reflect.Map:
+		return fromTypedMap(srcv, ref)
+	case reflect.Slice:
+		return fromTypedSlice(srcv, ref)
+	case reflect.String:
+		return fromTypedString(srcv, ref)
+	case reflect.Bool:
+		return fromTypedBool(srcv, ref)
+	case reflect.Int, reflect.Int32, reflect.Int64:
+		return fromTypedInt(srcv, ref)
+	case reflect.Float32, reflect.Float64:
+		return fromTypedFloat(srcv, ref)
+	}
+
+	return config.NilValue, fmt.Errorf("unsupported type: %s", srcv.Kind())
+}
+
+func fromTypedStruct(src reflect.Value, ref config.Value) (config.Value, error) {
+	// Check that the reference value is compatible or nil.
+	switch ref.Kind() {
+	case config.KindMap, config.KindNil:
+	default:
+		return config.Value{}, fmt.Errorf("unhandled type: %s", ref.Kind())
+	}
+
+	out := make(map[string]config.Value)
+	info := getStructInfo(src.Type())
+	for k, v := range info.FieldValues(src) {
+		// Convert the field taking into account the reference value (may be equal to config.NilValue).
+		nv, err := FromTyped(v.Interface(), ref.Get(k))
+		if err != nil {
+			return config.Value{}, err
+		}
+
+		if nv != config.NilValue {
+			out[k] = nv
+		}
+	}
+
+	// If the struct was equal to its zero value, emit a nil.
+	if len(out) == 0 {
+		return config.NilValue, nil
+	}
+
+	return config.NewValue(out, ref.Location()), nil
+}
+
+func fromTypedMap(src reflect.Value, ref config.Value) (config.Value, error) {
+	// Check that the reference value is compatible or nil.
+	switch ref.Kind() {
+	case config.KindMap, config.KindNil:
+	default:
+		return config.Value{}, fmt.Errorf("unhandled type: %s", ref.Kind())
+	}
+
+	// Return nil if the map is nil.
+	if src.IsNil() {
+		return config.NilValue, nil
+	}
+
+	out := make(map[string]config.Value)
+	iter := src.MapRange()
+	for iter.Next() {
+		k := iter.Key().String()
+		v := iter.Value()
+
+		// Convert entry taking into account the reference value (may be equal to config.NilValue).
+		nv, err := FromTyped(v.Interface(), ref.Get(k))
+		if err != nil {
+			return config.Value{}, err
+		}
+
+		// Every entry is represented, even if it is a nil.
+		// Otherwise, a map with zero-valued structs would yield a nil as well.
+		out[k] = nv
+	}
+
+	return config.NewValue(out, ref.Location()), nil
+}
+
+func fromTypedSlice(src reflect.Value, ref config.Value) (config.Value, error) {
+	// Check that the reference value is compatible or nil.
+	switch ref.Kind() {
+	case config.KindSequence, config.KindNil:
+	default:
+		return config.Value{}, fmt.Errorf("unhandled type: %s", ref.Kind())
+	}
+
+	// Return nil if the slice is nil.
+	if src.IsNil() {
+		return config.NilValue, nil
+	}
+
+	out := make([]config.Value, src.Len())
+	for i := 0; i < src.Len(); i++ {
+		v := src.Index(i)
+
+		// Convert entry taking into account the reference value (may be equal to config.NilValue).
+		nv, err := FromTyped(v.Interface(), ref.Index(i))
+		if err != nil {
+			return config.Value{}, err
+		}
+
+		out[i] = nv
+	}
+
+	return config.NewValue(out, ref.Location()), nil
+}
+
+func fromTypedString(src reflect.Value, ref config.Value) (config.Value, error) {
+	switch ref.Kind() {
+	case config.KindString:
+		value := src.String()
+		if value == ref.MustString() {
+			return ref, nil
+		}
+
+		return config.V(value), nil
+	case config.KindNil:
+		// This field is not set in the reference, so we only include it if it has a non-zero value.
+		// Otherwise, we would always include all zero valued fields.
+		if src.IsZero() {
+			return config.NilValue, nil
+		}
+		return config.V(src.String()), nil
+	}
+
+	return config.Value{}, fmt.Errorf("unhandled type: %s", ref.Kind())
+}
+
+func fromTypedBool(src reflect.Value, ref config.Value) (config.Value, error) {
+	switch ref.Kind() {
+	case config.KindBool:
+		value := src.Bool()
+		if value == ref.MustBool() {
+			return ref, nil
+		}
+		return config.V(value), nil
+	case config.KindNil:
+		// This field is not set in the reference, so we only include it if it has a non-zero value.
+		// Otherwise, we would always include all zero valued fields.
+		if src.IsZero() {
+			return config.NilValue, nil
+		}
+		return config.V(src.Bool()), nil
+	}
+
+	return config.Value{}, fmt.Errorf("unhandled type: %s", ref.Kind())
+}
+
+func fromTypedInt(src reflect.Value, ref config.Value) (config.Value, error) {
+	switch ref.Kind() {
+	case config.KindInt:
+		value := src.Int()
+		if value == ref.MustInt() {
+			return ref, nil
+		}
+		return config.V(value), nil
+	case config.KindNil:
+		// This field is not set in the reference, so we only include it if it has a non-zero value.
+		// Otherwise, we would always include all zero valued fields.
+		if src.IsZero() {
+			return config.NilValue, nil
+		}
+		return config.V(src.Int()), nil
+	}
+
+	return config.Value{}, fmt.Errorf("unhandled type: %s", ref.Kind())
+}
+
+func fromTypedFloat(src reflect.Value, ref config.Value) (config.Value, error) {
+	switch ref.Kind() {
+	case config.KindFloat:
+		value := src.Float()
+		if value == ref.MustFloat() {
+			return ref, nil
+		}
+		return config.V(value), nil
+	case config.KindNil:
+		// This field is not set in the reference, so we only include it if it has a non-zero value.
+		// Otherwise, we would always include all zero valued fields.
+		if src.IsZero() {
+			return config.NilValue, nil
+		}
+		return config.V(src.Float()), nil
+	}
+
+	return config.Value{}, fmt.Errorf("unhandled type: %s", ref.Kind())
+}
--- a/libs/config/convert/from_typed_test.go
+++ b/libs/config/convert/from_typed_test.go
@ -0,0 +1,394 @@
+package convert
+
+import (
+	"testing"
+
+	"github.com/databricks/cli/libs/config"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestFromTypedStructZeroFields(t *testing.T) {
+	type Tmp struct {
+		Foo string `json:"foo"`
+		Bar string `json:"bar"`
+	}
+
+	src := Tmp{}
+	ref := config.NilValue
+
+	nv, err := FromTyped(src, ref)
+	require.NoError(t, err)
+	assert.Equal(t, config.NilValue, nv)
+}
+
+func TestFromTypedStructSetFields(t *testing.T) {
+	type Tmp struct {
+		Foo string `json:"foo"`
+		Bar string `json:"bar"`
+	}
+
+	src := Tmp{
+		Foo: "foo",
+		Bar: "bar",
+	}
+
+	ref := config.NilValue
+	nv, err := FromTyped(src, ref)
+	require.NoError(t, err)
+	assert.Equal(t, config.V(map[string]config.Value{
+		"foo": config.V("foo"),
+		"bar": config.V("bar"),
+	}), nv)
+}
+
+func TestFromTypedStructSetFieldsRetainLocationIfUnchanged(t *testing.T) {
+	type Tmp struct {
+		Foo string `json:"foo"`
+		Bar string `json:"bar"`
+	}
+
+	src := Tmp{
+		Foo: "bar",
+		Bar: "qux",
+	}
+
+	ref := config.V(map[string]config.Value{
+		"foo": config.NewValue("bar", config.Location{File: "foo"}),
+		"bar": config.NewValue("baz", config.Location{File: "bar"}),
+	})
+
+	nv, err := FromTyped(src, ref)
+	require.NoError(t, err)
+
+	// Assert foo has retained its location.
+	assert.Equal(t, config.NewValue("bar", config.Location{File: "foo"}), nv.Get("foo"))
+
+	// Assert bar lost its location (because it was overwritten).
+	assert.Equal(t, config.NewValue("qux", config.Location{}), nv.Get("bar"))
+}
+
+func TestFromTypedMapNil(t *testing.T) {
+	var src map[string]string = nil
+
+	ref := config.V(map[string]config.Value{
+		"foo": config.V("bar"),
+		"bar": config.V("baz"),
+	})
+
+	nv, err := FromTyped(src, ref)
+	require.NoError(t, err)
+	assert.Equal(t, config.NilValue, nv)
+}
+
+func TestFromTypedMapEmpty(t *testing.T) {
+	var src = map[string]string{}
+
+	ref := config.V(map[string]config.Value{
+		"foo": config.V("bar"),
+		"bar": config.V("baz"),
+	})
+
+	nv, err := FromTyped(src, ref)
+	require.NoError(t, err)
+	assert.Equal(t, config.V(map[string]config.Value{}), nv)
+}
+
+func TestFromTypedMapNonEmpty(t *testing.T) {
+	var src = map[string]string{
+		"foo": "foo",
+		"bar": "bar",
+	}
+
+	ref := config.NilValue
+	nv, err := FromTyped(src, ref)
+	require.NoError(t, err)
+	assert.Equal(t, config.V(map[string]config.Value{
+		"foo": config.V("foo"),
+		"bar": config.V("bar"),
+	}), nv)
+}
+
+func TestFromTypedMapNonEmptyRetainLocationIfUnchanged(t *testing.T) {
+	var src = map[string]string{
+		"foo": "bar",
+		"bar": "qux",
+	}
+
+	ref := config.V(map[string]config.Value{
+		"foo": config.NewValue("bar", config.Location{File: "foo"}),
+		"bar": config.NewValue("baz", config.Location{File: "bar"}),
+	})
+
+	nv, err := FromTyped(src, ref)
+	require.NoError(t, err)
+
+	// Assert foo has retained its location.
+	assert.Equal(t, config.NewValue("bar", config.Location{File: "foo"}), nv.Get("foo"))
+
+	// Assert bar lost its location (because it was overwritten).
+	assert.Equal(t, config.NewValue("qux", config.Location{}), nv.Get("bar"))
+}
+
+func TestFromTypedMapFieldWithZeroValue(t *testing.T) {
+	var src = map[string]string{
+		"foo": "",
+	}
+
+	ref := config.NilValue
+	nv, err := FromTyped(src, ref)
+	require.NoError(t, err)
+	assert.Equal(t, config.V(map[string]config.Value{
+		"foo": config.NilValue,
+	}), nv)
+}
+
+func TestFromTypedSliceNil(t *testing.T) {
+	var src []string = nil
+
+	ref := config.V([]config.Value{
+		config.V("bar"),
+		config.V("baz"),
+	})
+
+	nv, err := FromTyped(src, ref)
+	require.NoError(t, err)
+	assert.Equal(t, config.NilValue, nv)
+}
+
+func TestFromTypedSliceEmpty(t *testing.T) {
+	var src = []string{}
+
+	ref := config.V([]config.Value{
+		config.V("bar"),
+		config.V("baz"),
+	})
+
+	nv, err := FromTyped(src, ref)
+	require.NoError(t, err)
+	assert.Equal(t, config.V([]config.Value{}), nv)
+}
+
+func TestFromTypedSliceNonEmpty(t *testing.T) {
+	var src = []string{
+		"foo",
+		"bar",
+	}
+
+	ref := config.NilValue
+	nv, err := FromTyped(src, ref)
+	require.NoError(t, err)
+	assert.Equal(t, config.V([]config.Value{
+		config.V("foo"),
+		config.V("bar"),
+	}), nv)
+}
+
+func TestFromTypedSliceNonEmptyRetainLocationIfUnchanged(t *testing.T) {
+	var src = []string{
+		"foo",
+		"bar",
+	}
+
+	ref := config.V([]config.Value{
+		config.NewValue("foo", config.Location{File: "foo"}),
+		config.NewValue("baz", config.Location{File: "baz"}),
+	})
+
+	nv, err := FromTyped(src, ref)
+	require.NoError(t, err)
+
+	// Assert foo has retained its location.
+	assert.Equal(t, config.NewValue("foo", config.Location{File: "foo"}), nv.Index(0))
+
+	// Assert bar lost its location (because it was overwritten).
+	assert.Equal(t, config.NewValue("bar", config.Location{}), nv.Index(1))
+}
+
+func TestFromTypedStringEmpty(t *testing.T) {
+	var src string
+	var ref = config.NilValue
+	nv, err := FromTyped(src, ref)
+	require.NoError(t, err)
+	assert.Equal(t, config.NilValue, nv)
+}
+
+func TestFromTypedStringEmptyOverwrite(t *testing.T) {
+	var src string
+	var ref = config.V("old")
+	nv, err := FromTyped(src, ref)
+	require.NoError(t, err)
+	assert.Equal(t, config.V(""), nv)
+}
+
+func TestFromTypedStringNonEmpty(t *testing.T) {
+	var src string = "new"
+	var ref = config.NilValue
+	nv, err := FromTyped(src, ref)
+	require.NoError(t, err)
+	assert.Equal(t, config.V("new"), nv)
+}
+
+func TestFromTypedStringNonEmptyOverwrite(t *testing.T) {
+	var src string = "new"
+	var ref = config.V("old")
+	nv, err := FromTyped(src, ref)
+	require.NoError(t, err)
+	assert.Equal(t, config.V("new"), nv)
+}
+
+func TestFromTypedStringRetainsLocationsIfUnchanged(t *testing.T) {
+	var src string = "foo"
+	var ref = config.NewValue("foo", config.Location{File: "foo"})
+	nv, err := FromTyped(src, ref)
+	require.NoError(t, err)
+	assert.Equal(t, config.NewValue("foo", config.Location{File: "foo"}), nv)
+}
+
+func TestFromTypedStringTypeError(t *testing.T) {
+	var src string = "foo"
+	var ref = config.V(1234)
+	_, err := FromTyped(src, ref)
+	require.Error(t, err)
+}
+
+func TestFromTypedBoolEmpty(t *testing.T) {
+	var src bool
+	var ref = config.NilValue
+	nv, err := FromTyped(src, ref)
+	require.NoError(t, err)
+	assert.Equal(t, config.NilValue, nv)
+}
+
+func TestFromTypedBoolEmptyOverwrite(t *testing.T) {
+	var src bool
+	var ref = config.V(true)
+	nv, err := FromTyped(src, ref)
+	require.NoError(t, err)
+	assert.Equal(t, config.V(false), nv)
+}
+
+func TestFromTypedBoolNonEmpty(t *testing.T) {
+	var src bool = true
+	var ref = config.NilValue
+	nv, err := FromTyped(src, ref)
+	require.NoError(t, err)
+	assert.Equal(t, config.V(true), nv)
+}
+
+func TestFromTypedBoolNonEmptyOverwrite(t *testing.T) {
+	var src bool = true
+	var ref = config.V(false)
+	nv, err := FromTyped(src, ref)
+	require.NoError(t, err)
+	assert.Equal(t, config.V(true), nv)
+}
+
+func TestFromTypedBoolRetainsLocationsIfUnchanged(t *testing.T) {
+	var src bool = true
+	var ref = config.NewValue(true, config.Location{File: "foo"})
+	nv, err := FromTyped(src, ref)
+	require.NoError(t, err)
+	assert.Equal(t, config.NewValue(true, config.Location{File: "foo"}), nv)
+}
+
+func TestFromTypedBoolTypeError(t *testing.T) {
+	var src bool = true
+	var ref = config.V("string")
+	_, err := FromTyped(src, ref)
+	require.Error(t, err)
+}
+
+func TestFromTypedIntEmpty(t *testing.T) {
+	var src int
+	var ref = config.NilValue
+	nv, err := FromTyped(src, ref)
+	require.NoError(t, err)
+	assert.Equal(t, config.NilValue, nv)
+}
+
+func TestFromTypedIntEmptyOverwrite(t *testing.T) {
+	var src int
+	var ref = config.V(1234)
+	nv, err := FromTyped(src, ref)
+	require.NoError(t, err)
+	assert.Equal(t, config.V(int64(0)), nv)
+}
+
+func TestFromTypedIntNonEmpty(t *testing.T) {
+	var src int = 1234
+	var ref = config.NilValue
+	nv, err := FromTyped(src, ref)
+	require.NoError(t, err)
+	assert.Equal(t, config.V(int64(1234)), nv)
+}
+
+func TestFromTypedIntNonEmptyOverwrite(t *testing.T) {
+	var src int = 1234
+	var ref = config.V(1233)
+	nv, err := FromTyped(src, ref)
+	require.NoError(t, err)
+	assert.Equal(t, config.V(int64(1234)), nv)
+}
+
+func TestFromTypedIntRetainsLocationsIfUnchanged(t *testing.T) {
+	var src int = 1234
+	var ref = config.NewValue(1234, config.Location{File: "foo"})
+	nv, err := FromTyped(src, ref)
+	require.NoError(t, err)
+	assert.Equal(t, config.NewValue(1234, config.Location{File: "foo"}), nv)
+}
+
+func TestFromTypedIntTypeError(t *testing.T) {
+	var src int = 1234
+	var ref = config.V("string")
+	_, err := FromTyped(src, ref)
+	require.Error(t, err)
+}
+
+func TestFromTypedFloatEmpty(t *testing.T) {
+	var src float64
+	var ref = config.NilValue
+	nv, err := FromTyped(src, ref)
+	require.NoError(t, err)
+	assert.Equal(t, config.NilValue, nv)
+}
+
+func TestFromTypedFloatEmptyOverwrite(t *testing.T) {
+	var src float64
+	var ref = config.V(1.23)
+	nv, err := FromTyped(src, ref)
+	require.NoError(t, err)
+	assert.Equal(t, config.V(0.0), nv)
+}
+
+func TestFromTypedFloatNonEmpty(t *testing.T) {
+	var src float64 = 1.23
+	var ref = config.NilValue
+	nv, err := FromTyped(src, ref)
+	require.NoError(t, err)
+	assert.Equal(t, config.V(1.23), nv)
+}
+
+func TestFromTypedFloatNonEmptyOverwrite(t *testing.T) {
+	var src float64 = 1.23
+	var ref = config.V(1.24)
+	nv, err := FromTyped(src, ref)
+	require.NoError(t, err)
+	assert.Equal(t, config.V(1.23), nv)
+}
+
+func TestFromTypedFloatRetainsLocationsIfUnchanged(t *testing.T) {
+	var src float64 = 1.23
+	var ref = config.NewValue(1.23, config.Location{File: "foo"})
+	nv, err := FromTyped(src, ref)
+	require.NoError(t, err)
+	assert.Equal(t, config.NewValue(1.23, config.Location{File: "foo"}), nv)
+}
+
+func TestFromTypedFloatTypeError(t *testing.T) {
+	var src float64 = 1.23
+	var ref = config.V("string")
+	_, err := FromTyped(src, ref)
+	require.Error(t, err)
+}
--- a/libs/config/convert/struct_info.go
+++ b/libs/config/convert/struct_info.go
@ -85,3 +85,31 @@ func buildStructInfo(typ reflect.Type) structInfo {

 	return out
 }
+
+func (s *structInfo) FieldValues(v reflect.Value) map[string]reflect.Value {
+	var out = make(map[string]reflect.Value)
+
+	for k, index := range s.Fields {
+		fv := v
+
+		// Locate value in struct (it could be an embedded type).
+		for i, x := range index {
+			if i > 0 {
+				if fv.Kind() == reflect.Pointer && fv.Type().Elem().Kind() == reflect.Struct {
+					if fv.IsNil() {
+						fv = reflect.Value{}
+						break
+					}
+					fv = fv.Elem()
+				}
+			}
+			fv = fv.Field(x)
+		}
+
+		if fv.IsValid() {
+			out[k] = fv
+		}
+	}
+
+	return out
+}
--- a/libs/config/convert/struct_info_test.go
+++ b/libs/config/convert/struct_info_test.go
@ -87,3 +87,110 @@ func TestStructInfoAnonymousByPointer(t *testing.T) {
 	assert.Equal(t, []int{0, 0}, si.Fields["foo"])
 	assert.Equal(t, []int{0, 1, 0}, si.Fields["bar"])
 }
+
+func TestStructInfoFieldValues(t *testing.T) {
+	type Tmp struct {
+		Foo string `json:"foo"`
+		Bar string `json:"bar"`
+	}
+
+	var src = Tmp{
+		Foo: "foo",
+		Bar: "bar",
+	}
+
+	si := getStructInfo(reflect.TypeOf(Tmp{}))
+	fv := si.FieldValues(reflect.ValueOf(src))
+	assert.Len(t, fv, 2)
+	assert.Equal(t, "foo", fv["foo"].String())
+	assert.Equal(t, "bar", fv["bar"].String())
+}
+
+func TestStructInfoFieldValuesAnonymousByValue(t *testing.T) {
+	type Bar struct {
+		Bar string `json:"bar"`
+	}
+
+	type Foo struct {
+		Foo string `json:"foo"`
+		Bar
+	}
+
+	type Tmp struct {
+		Foo
+	}
+
+	var src = Tmp{
+		Foo: Foo{
+			Foo: "foo",
+			Bar: Bar{
+				Bar: "bar",
+			},
+		},
+	}
+
+	si := getStructInfo(reflect.TypeOf(Tmp{}))
+	fv := si.FieldValues(reflect.ValueOf(src))
+	assert.Len(t, fv, 2)
+	assert.Equal(t, "foo", fv["foo"].String())
+	assert.Equal(t, "bar", fv["bar"].String())
+}
+
+func TestStructInfoFieldValuesAnonymousByPointer(t *testing.T) {
+	type Bar struct {
+		Bar string `json:"bar"`
+	}
+
+	type Foo struct {
+		Foo string `json:"foo"`
+		*Bar
+	}
+
+	type Tmp struct {
+		*Foo
+	}
+
+	// Test that the embedded fields are dereferenced properly.
+	t.Run("all are set", func(t *testing.T) {
+		src := Tmp{
+			Foo: &Foo{
+				Foo: "foo",
+				Bar: &Bar{
+					Bar: "bar",
+				},
+			},
+		}
+
+		si := getStructInfo(reflect.TypeOf(Tmp{}))
+		fv := si.FieldValues(reflect.ValueOf(src))
+		assert.Len(t, fv, 2)
+		assert.Equal(t, "foo", fv["foo"].String())
+		assert.Equal(t, "bar", fv["bar"].String())
+	})
+
+	// Test that fields of embedded types are skipped if the embedded type is nil.
+	t.Run("top level is set", func(t *testing.T) {
+		src := Tmp{
+			Foo: &Foo{
+				Foo: "foo",
+				Bar: nil,
+			},
+		}
+
+		si := getStructInfo(reflect.TypeOf(Tmp{}))
+		fv := si.FieldValues(reflect.ValueOf(src))
+		assert.Len(t, fv, 1)
+		assert.Equal(t, "foo", fv["foo"].String())
+	})
+
+	// Test that fields of embedded types are skipped if the embedded type is nil.
+	t.Run("none are set", func(t *testing.T) {
+		src := Tmp{
+			Foo: nil,
+		}
+
+		si := getStructInfo(reflect.TypeOf(Tmp{}))
+		fv := si.FieldValues(reflect.ValueOf(src))
+		assert.Empty(t, fv)
+	})
+}
--- a/libs/config/convert/to_typed.go
+++ b/libs/config/convert/to_typed.go
@ -13,6 +13,12 @@ func ToTyped(dst any, src config.Value) error {

 	// Dereference pointer if necessary
 	for dstv.Kind() == reflect.Pointer {
+		// If the source value is nil and the destination is a settable pointer,
+		// set the destination to nil. Also see `end_to_end_test.go`.
+		if dstv.CanSet() && src == config.NilValue {
+			dstv.SetZero()
+			return nil
+		}
 		if dstv.IsNil() {
 			dstv.Set(reflect.New(dstv.Type().Elem()))
 		}