kubernetes · liggitt · Jul 30, 2025 · Jul 29, 2025 · Jul 30, 2025 · Jul 29, 2025
diff --git a/api/api-rules/codegen_violation_exceptions.list b/api/api-rules/codegen_violation_exceptions.list
@@ -7,3 +7,5 @@ API rule violation: names_match,k8s.io/apimachinery/pkg/apis/meta/v1,StatusCause
 API rule violation: names_match,k8s.io/apimachinery/pkg/apis/meta/v1,Time,Time
 API rule violation: names_match,k8s.io/apimachinery/pkg/runtime,Unknown,ContentEncoding
 API rule violation: names_match,k8s.io/apimachinery/pkg/runtime,Unknown,ContentType
+API rule violation: names_match,k8s.io/code-generator/examples/apiserver/apis/example/v1,ConversionCustom,privateField
+API rule violation: names_match,k8s.io/code-generator/examples/apiserver/apis/example/v1,ConversionPrivate,privateField
diff --git a/staging/src/k8s.io/code-generator/cmd/conversion-gen/generators/conversion.go b/staging/src/k8s.io/code-generator/cmd/conversion-gen/generators/conversion.go
@@ -685,6 +685,16 @@ func (g *genConversion) preexists(inType, outType *types.Type) (*types.Type, boo
 	return function, ok
 }
 
+func (g *genConversion) preexistsPointers(inType, outType *types.Type) (*types.Type, bool) {
+	if inType.Kind != types.Pointer {
+		return nil, false
+	}
+	if outType.Kind != types.Pointer {
+		return nil, false
+	}
+	return g.preexists(inType.Elem, outType.Elem)
+}
+
 func (g *genConversion) Init(c *generator.Context, w io.Writer) error {
 	klogV := klog.V(6)
 	if klogV.Enabled() {
@@ -864,9 +874,16 @@ func (g *genConversion) doMap(inType, outType *types.Type, sw *generator.Snippet
 			}
 		} else {
 			conversionExists := true
+			conditionalConversionExists := false
 			if function, ok := g.preexists(inType.Elem, outType.Elem); ok {
 				sw.Do("newVal := new($.|raw$)\n", outType.Elem)
 				sw.Do("if err := $.|raw$(&val, newVal, s); err != nil {\n", function)
+			} else if function, ok := g.preexistsPointers(inType.Elem, outType.Elem); ok {
+				sw.Do("newVal := new($.|raw$)\n", outType.Elem)
+				sw.Do("if val != nil {\n", nil)
+				sw.Do("*newVal = new($.|raw$)\n", outType.Elem.Elem)
+				sw.Do("if err := $.|raw$(val, *newVal, s); err != nil {\n", function)
+				conditionalConversionExists = true
 			} else if g.convertibleOnlyWithinPackage(inType.Elem, outType.Elem) {
 				sw.Do("newVal := new($.|raw$)\n", outType.Elem)
 				sw.Do("if err := "+nameTmpl+"(&val, newVal, s); err != nil {\n", argsFromType(inType.Elem, outType.Elem))
@@ -879,6 +896,9 @@ func (g *genConversion) doMap(inType, outType *types.Type, sw *generator.Snippet
 			if conversionExists {
 				sw.Do("return err\n", nil)
 				sw.Do("}\n", nil)
+				if conditionalConversionExists {
+					sw.Do("}\n", nil)
+				}
 				if inType.Key == outType.Key {
 					sw.Do("(*out)[key] = *newVal\n", nil)
 				} else {
@@ -908,8 +928,14 @@ func (g *genConversion) doSlice(inType, outType *types.Type, sw *generator.Snipp
 			}
 		} else {
 			conversionExists := true
+			conditionalConversionExists := false
 			if function, ok := g.preexists(inType.Elem, outType.Elem); ok {
 				sw.Do("if err := $.|raw$(&(*in)[i], &(*out)[i], s); err != nil {\n", function)
+			} else if function, ok := g.preexistsPointers(inType.Elem, outType.Elem); ok {
+				sw.Do("if (*in)[i] != nil {\n", nil)
+				sw.Do("(*out)[i] = new($.|raw$)\n", outType.Elem.Elem)
+				sw.Do("if err := $.|raw$((*in)[i], (*out)[i], s); err != nil {\n", function)
+				conditionalConversionExists = true
 			} else if g.convertibleOnlyWithinPackage(inType.Elem, outType.Elem) {
 				sw.Do("if err := "+nameTmpl+"(&(*in)[i], &(*out)[i], s); err != nil {\n", argsFromType(inType.Elem, outType.Elem))
 			} else {
@@ -921,6 +947,9 @@ func (g *genConversion) doSlice(inType, outType *types.Type, sw *generator.Snipp
 			if conversionExists {
 				sw.Do("return err\n", nil)
 				sw.Do("}\n", nil)
+				if conditionalConversionExists {
+					sw.Do("}\n", nil)
+				}
 			}
 		}
 		sw.Do("}\n", nil)
@@ -946,6 +975,17 @@ func (g *genConversion) doStruct(inType, outType *types.Type, sw *generator.Snip
 			continue
 		}
 
+		if namer.IsPrivateGoName(inMember.Name) && g.outputPackage != inType.Name.Package {
+			sw.Do("// WARNING: in."+inMember.Name+" is not exported and cannot be read\n", nil)
+			g.skippedFields[inType] = append(g.skippedFields[inType], inMember.Name)
+			continue
+		}
+		if namer.IsPrivateGoName(outMember.Name) && g.outputPackage != outType.Name.Package {
+			sw.Do("// WARNING: out."+inMember.Name+" is not exported and cannot be set\n", nil)
+			g.skippedFields[inType] = append(g.skippedFields[inType], inMember.Name)
+			continue
+		}
+
 		inMemberType, outMemberType := inMember.Type, outMember.Type
 		// create a copy of both underlying types but give them the top level alias name (since aliases
 		// are assignable)

diff --git a/staging/src/k8s.io/code-generator/examples/apiserver/apis/example/types.go b/staging/src/k8s.io/code-generator/examples/apiserver/apis/example/types.go
@@ -62,3 +62,21 @@ type MemoryDifferent struct {
 	AllOf      []MemoryDifferent
 	Bool       bool // differs from external representation
 }
+
+type ConversionPrivate struct {
+	PublicField  string
+	privateField string
+}
+
+type ConversionCustomContainer struct {
+	Slice   []ConversionCustom
+	SliceP  []*ConversionCustom
+	Map     map[string]ConversionCustom
+	MapP    map[string]*ConversionCustom
+	Struct  ConversionCustom
+	StructP *ConversionCustom
+}
+type ConversionCustom struct {
+	PublicField  string
+	privateField string
+}
diff --git a/staging/src/k8s.io/code-generator/examples/apiserver/apis/example/v1/conversion.go b/staging/src/k8s.io/code-generator/examples/apiserver/apis/example/v1/conversion.go
@@ -0,0 +1,42 @@
+/*
+Copyright 2025 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package v1
+
+import (
+	conversion "k8s.io/apimachinery/pkg/conversion"
+	example "k8s.io/code-generator/examples/apiserver/apis/example"
+)
+
+// manually created final conversion function required because the object contains private fields that cannot be auto-converted
+func Convert_v1_ConversionPrivate_To_example_ConversionPrivate(in *ConversionPrivate, out *example.ConversionPrivate, scope conversion.Scope) error {
+	return autoConvert_v1_ConversionPrivate_To_example_ConversionPrivate(in, out, scope)
+}
+
+// manually created final conversion function required because the object contains private fields that cannot be auto-converted
+func Convert_example_ConversionPrivate_To_v1_ConversionPrivate(in *example.ConversionPrivate, out *ConversionPrivate, scope conversion.Scope) error {
+	return autoConvert_example_ConversionPrivate_To_v1_ConversionPrivate(in, out, scope)
+}
+
+// custom conversion function to exercise use of custom functions in slice/map/pointer fields
+func Convert_v1_ConversionCustom_To_example_ConversionCustom(in *ConversionCustom, out *example.ConversionCustom, scope conversion.Scope) error {
+	return autoConvert_v1_ConversionCustom_To_example_ConversionCustom(in, out, scope)
+}
+
+// custom conversion function to exercise use of custom functions in slice/map/pointer fields
+func Convert_example_ConversionCustom_To_v1_ConversionCustom(in *example.ConversionCustom, out *ConversionCustom, scope conversion.Scope) error {
+	return autoConvert_example_ConversionCustom_To_v1_ConversionCustom(in, out, scope)
+}
diff --git a/staging/src/k8s.io/code-generator/examples/apiserver/apis/example/v1/conversion_test.go b/staging/src/k8s.io/code-generator/examples/apiserver/apis/example/v1/conversion_test.go
@@ -0,0 +1,87 @@
+/*
+Copyright 2025 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package v1
+
+import (
+	"reflect"
+	"testing"
+
+	"k8s.io/code-generator/examples/apiserver/apis/example"
+)
+
+func TestConversion(t *testing.T) {
+	testcases := []struct {
+		name string
+		in   *ConversionCustomContainer
+	}{
+		{
+			name: "nil",
+			in:   &ConversionCustomContainer{},
+		},
+		{
+			name: "empty",
+			in: &ConversionCustomContainer{
+				Slice:   []ConversionCustom{},
+				SliceP:  []*ConversionCustom{},
+				Map:     map[string]ConversionCustom{},
+				MapP:    map[string]*ConversionCustom{},
+				Struct:  ConversionCustom{},
+				StructP: &ConversionCustom{},
+			},
+		},
+		{
+			name: "nil_entries",
+			in: &ConversionCustomContainer{
+				Slice:  []ConversionCustom{{}},
+				SliceP: []*ConversionCustom{nil},
+				Map:    map[string]ConversionCustom{"key": {}},
+				MapP:   map[string]*ConversionCustom{"key": nil},
+			},
+		},
+		{
+			name: "set_entries",
+			in: &ConversionCustomContainer{
+				Slice:   []ConversionCustom{{PublicField: "test1"}},
+				SliceP:  []*ConversionCustom{{PublicField: "test2"}},
+				Map:     map[string]ConversionCustom{"key": {PublicField: "test3"}},
+				MapP:    map[string]*ConversionCustom{"key": {PublicField: "test4"}},
+				Struct:  ConversionCustom{PublicField: "test5"},
+				StructP: &ConversionCustom{PublicField: "test6"},
+			},
+		},
+	}
+
+	for _, tc := range testcases {
+		t.Run(tc.name, func(t *testing.T) {
+			original := tc.in.DeepCopy()
+
+			out := &example.ConversionCustomContainer{}
+			if err := Convert_v1_ConversionCustomContainer_To_example_ConversionCustomContainer(tc.in, out, nil); err != nil {
+				t.Fatal(err)
+			}
+
+			roundtrip := &ConversionCustomContainer{}
+			if err := Convert_example_ConversionCustomContainer_To_v1_ConversionCustomContainer(out, roundtrip, nil); err != nil {
+				t.Fatal(err)
+			}
+
+			if !reflect.DeepEqual(original, roundtrip) {
+				t.Fatalf("expected:\n%#v\ngot:\n%#v", original, roundtrip)
+			}
+		})
+	}
+}
diff --git a/staging/src/k8s.io/code-generator/examples/apiserver/apis/example/v1/types.go b/staging/src/k8s.io/code-generator/examples/apiserver/apis/example/v1/types.go
@@ -70,3 +70,23 @@ type MemoryDifferent struct {
 
 	Bool *bool `json:"bool"` // differs from internal representation
 }
+
+type ConversionPrivate struct {
+	PublicField  string `json:"publicField"`
+	privateField string `json:"privateField"`
+}
+
+type ConversionCustomContainer struct {
+	// +listType=atomic
+	Slice []ConversionCustom `json:"slice"`
+	// +listType=atomic
+	SliceP  []*ConversionCustom          `json:"sliceP"`
+	Map     map[string]ConversionCustom  `json:"map"`
+	MapP    map[string]*ConversionCustom `json:"mapP"`
+	Struct  ConversionCustom             `json:"struct"`
+	StructP *ConversionCustom            `json:"structP"`
+}
+type ConversionCustom struct {
+	PublicField  string `json:"publicField"`
+	privateField string `json:"privateField"`
+}