Extract CheckStructuralSubset implementation.

CheckStructuralSubset function has path passed for better error
reporting. This implementation detail shouldn't be exposed in public
API.

pkg/cloud/api/check.go

@@ -174,8 +174,14 @@ func checkSchema(t reflect.Type) error {
 
 // CheckStructuralSubset checks if type From is the subset of To type. Type is a
 // subset of another if it contains fields with the same type and name. This
-// function is not symmetric. Path parameter is used for better error reporting.
-func CheckStructuralSubset(p Path, from, to reflect.Type) error {
+// function is not symmetric.
+func CheckStructuralSubset(from, to reflect.Type) error {
+	return checkStructuralSubsetImpl(Path{}, from, to)
+}
+
+// checkStructuralSubsetImpl this is recursive function to check if type From is
+// a subset of To type. Path parameter is used for better error reporting.
+func checkStructuralSubsetImpl(p Path, from, to reflect.Type) error {
 	if from.Kind() != to.Kind() {
 		return fmt.Errorf("%s has different type: %v != %v", p, from.Kind(), to.Kind())
 	}
@@ -184,7 +190,7 @@ func CheckStructuralSubset(p Path, from, to reflect.Type) error {
 	}
 	switch from.Kind() {
 	case reflect.Pointer:
-		return CheckStructuralSubset(p.Pointer(), from.Elem(), to.Elem())
+		return checkStructuralSubsetImpl(p.Pointer(), from.Elem(), to.Elem())
 
 	case reflect.Struct:
 		for i := 0; i < from.NumField(); i++ {
@@ -193,22 +199,22 @@ func CheckStructuralSubset(p Path, from, to reflect.Type) error {
 			if !exist {
 				return fmt.Errorf("%s: type %T does not have field %v", p.String(), to, af.Name)
 			}
-			if err := CheckStructuralSubset(p.Field(af.Name), af.Type, bf.Type); err != nil {
+			if err := checkStructuralSubsetImpl(p.Field(af.Name), af.Type, bf.Type); err != nil {
 				return err
 			}
 		}
 		return nil
 
 	case reflect.Slice, reflect.Array:
-		return CheckStructuralSubset(p.AnySliceIndex(), from.Elem(), to.Elem())
+		return checkStructuralSubsetImpl(p.AnySliceIndex(), from.Elem(), to.Elem())
 
 	case reflect.Map:
 		path := p.AnyMapIndex()
-		err := CheckStructuralSubset(path, from.Key(), to.Key())
+		err := checkStructuralSubsetImpl(path, from.Key(), to.Key())
 		if err != nil {
 			return err
 		}
-		return CheckStructuralSubset(path, from.Elem(), to.Elem())
+		return checkStructuralSubsetImpl(path, from.Elem(), to.Elem())
 	}
 	return fmt.Errorf("%s Unsupported type %v", p.String(), from.Kind())
 }

pkg/cloud/api/check_test.go

@@ -528,7 +528,7 @@ func TestConvertToT(t *testing.T) {
 		},
 	} {
 		t.Run(tc.name, func(t *testing.T) {
-			err := CheckStructuralSubset(Path{}, reflect.TypeOf(tc.a), reflect.TypeOf(tc.b))
+			err := CheckStructuralSubset(reflect.TypeOf(tc.a), reflect.TypeOf(tc.b))
 			gotErr := err != nil
 			if gotErr != tc.wantErr {
 				t.Fatalf("CheckStructuralSubset() = %v; gotErr = %t, want %t", err, gotErr, tc.wantErr)

pkg/cloud/api/mutable_resource.go

@@ -222,7 +222,7 @@ func (u *mutableResource[GA, Alpha, Beta]) CheckSchema() error {
 
 func checkSubsetOf[T1 any, T2 any](t1 *T1, t2 *T2) error {
 
-	return CheckStructuralSubset(Path{}, reflect.TypeOf(t1), reflect.TypeOf(t2))
+	return CheckStructuralSubset(reflect.TypeOf(t1), reflect.TypeOf(t2))
 }
 
 func (u *mutableResource[GA, Alpha, Beta]) ResourceID() *cloud.ResourceID { return u.resourceID }