add support for custom deepcopy logic

pkg/deepcopy/deepcopy.go

@@ -30,6 +30,10 @@ func MustClone[T any](val T) T {
  return cloned
 }
 
+type Copier interface {
+ DeepCopy() (any, error)
+}
+
 func clone(val any) (any, error) {
  switch asserted := val.(type) {
  // Go native types
@@ -66,6 +70,10 @@ func clone(val any) (any, error) {
  case ast.String:
  return asserted, nil
 
+ // custom logic
+ case Copier:
+ return asserted.DeepCopy()
+
  default:
  return nil, fmt.Errorf("cannot deep-copy %T", val)
  }

pkg/deepcopy/deepcopy_test.go

@@ -8,6 +8,40 @@ import (
  "github.com/google/go-cmp/cmp"
 )
 
+type customCopier struct {
+ Value any
+}
+
+var _ Copier = customCopier{}
+
+func (c customCopier) DeepCopy() (any, error) {
+ copied, err := Clone(c.Value)
+ if err != nil {
+ return nil, err
+ }
+
+ return customCopier{
+ Value: copied,
+ }, nil
+}
+
+type customPtrCopier struct {
+ Value any
+}
+
+var _ Copier = &customPtrCopier{}
+
+func (c *customPtrCopier) DeepCopy() (any, error) {
+ copied, err := Clone(c.Value)
+ if err != nil {
+ return nil, err
+ }
+
+ return &customPtrCopier{
+ Value: copied,
+ }, nil
+}
+
 func TestCloneScalars(t *testing.T) {
  testcases := []struct {
  input any
@@ -75,7 +109,7 @@ func TestCloneScalars(t *testing.T) {
  }
 
  if !cmp.Equal(cloned, testcase.expected) {
- t.Fatalf("Unpected result:\n\n%s\n", renderDiff(testcase.expected, cloned))
+ t.Fatalf("Unexpected result:\n\n%s\n", renderDiff(testcase.expected, cloned))
  }
 
  if &cloned == &testcase.input {
@@ -120,7 +154,7 @@ func TestCloneMapDeep(t *testing.T) {
  }
 
  if !cmp.Equal(cloned, input) {
- t.Fatalf("Unpected result:\n\n%s\n", renderDiff(input, cloned))
+ t.Fatalf("Unexpected result:\n\n%s\n", renderDiff(input, cloned))
  }
 
  helloList := input["hello"].([]any)
@@ -164,7 +198,7 @@ func TestCloneSliceDeep(t *testing.T) {
  }
 
  if !cmp.Equal(cloned, input) {
- t.Fatalf("Unpected result:\n\n%s\n", renderDiff(input, cloned))
+ t.Fatalf("Unexpected result:\n\n%s\n", renderDiff(input, cloned))
  }
 
  helloObj := input[3].(map[string]any)
@@ -175,6 +209,34 @@ func TestCloneSliceDeep(t *testing.T) {
  }
 }
 
+func TestCustomCopier(t *testing.T) {
+ data := map[string]any{"foo": "bar"}
+ cc := customCopier{Value: data}
+
+ cloned, err := Clone(cc)
+ if err != nil {
+ t.Fatalf("Failed to clone: %v", err)
+ }
+
+ if !cmp.Equal(cc, cloned) {
+ t.Fatalf("Unexpected result:\n\n%s\n", renderDiff(cc, cloned))
+ }
+}
+
+func TestCustomPtrCopier(t *testing.T) {
+ data := map[string]any{"foo": "bar"}
+ cc := &customPtrCopier{Value: data}
+
+ cloned, err := Clone(cc)
+ if err != nil {
+ t.Fatalf("Failed to clone: %v", err)
+ }
+
+ if !cmp.Equal(cc, cloned) {
+ t.Fatalf("Unexpected result:\n\n%s\n", renderDiff(cc, cloned))
+ }
+}
+
 func renderDiff(expected any, actual any) string {
  var builder strings.Builder