daemon: marshal legacy registry.ServiceConfig extra fields for compatability

This change moves the logic that is used to marshal the legacy extra fields for `registry.ServiceConfig` type to the daemon backend.

Signed-off-by: Austin Vazquez <austin.vazquez@docker.com>

api/types/registry/registry.go

@@ -17,23 +17,6 @@ type ServiceConfig struct {
 	ExtraFields map[string]any `json:"-"`
 }
 
-// MarshalJSON implements a custom marshaler to include legacy fields
-// in API responses.
-func (sc *ServiceConfig) MarshalJSON() ([]byte, error) {
-	type tmp ServiceConfig
-	base, err := json.Marshal((*tmp)(sc))
-	if err != nil {
-		return nil, err
-	}
-	var merged map[string]any
-	_ = json.Unmarshal(base, &merged)
-
-	for k, v := range sc.ExtraFields {
-		merged[k] = v
-	}
-	return json.Marshal(merged)
-}
-
 // NetIPNet is the net.IPNet type, which can be marshalled and
 // unmarshalled to JSON
 type NetIPNet net.IPNet

api/types/registry/registry_test.go

@@ -1,32 +0,0 @@
-package registry
-
-import (
-	"encoding/json"
-	"testing"
-
-	"gotest.tools/v3/assert"
-	is "gotest.tools/v3/assert/cmp"
-)
-
-func TestServiceConfigMarshalLegacyFields(t *testing.T) {
-	t.Run("without legacy fields", func(t *testing.T) {
-		b, err := json.Marshal(&ServiceConfig{})
-		assert.NilError(t, err)
-		const expected = `{"IndexConfigs":null,"InsecureRegistryCIDRs":null,"Mirrors":null}`
-		assert.Check(t, is.Equal(string(b), expected), "Legacy nondistributable-artifacts fields should be omitted in output")
-	})
-
-	// Legacy fields should be returned when set to an empty slice. This is
-	// used for API versions < 1.49.
-	t.Run("with legacy fields", func(t *testing.T) {
-		b, err := json.Marshal(&ServiceConfig{
-			ExtraFields: map[string]any{
-				"AllowNondistributableArtifactsCIDRs":     json.RawMessage(nil),
-				"AllowNondistributableArtifactsHostnames": json.RawMessage(nil),
-			},
-		})
-		assert.NilError(t, err)
-		const expected = `{"AllowNondistributableArtifactsCIDRs":null,"AllowNondistributableArtifactsHostnames":null,"IndexConfigs":null,"InsecureRegistryCIDRs":null,"Mirrors":null}`
-		assert.Check(t, is.Equal(string(b), expected))
-	})
-}

daemon/server/router/system/info_response.go

@@ -24,12 +24,21 @@ func (ir *infoResponse) MarshalJSON() ([]byte, error) {
 	if err != nil {
 		return nil, err
 	}
-	if len(ir.extraFields) == 0 {
+	if len(ir.extraFields) == 0 && (ir.Info == nil || ir.Info.RegistryConfig == nil || len(ir.Info.RegistryConfig.ExtraFields) == 0) {
 		return base, nil
 	}
 	var merged map[string]any
 	_ = json.Unmarshal(base, &merged)
 
+	// Merge top-level extraFields
 	maps.Copy(merged, ir.extraFields)
+
+	// Merge RegistryConfig.ExtraFields if present
+	if ir.Info != nil && ir.Info.RegistryConfig != nil && len(ir.Info.RegistryConfig.ExtraFields) > 0 {
+		if rc, ok := merged["RegistryConfig"].(map[string]any); ok {
+			maps.Copy(rc, ir.Info.RegistryConfig.ExtraFields)
+		}
+	}
+
 	return json.Marshal(merged)
 }

daemon/server/router/system/info_response_test.go

@@ -5,7 +5,10 @@ import (
 	"strings"
 	"testing"
 
+	"github.com/moby/moby/api/types/registry"
 	"github.com/moby/moby/api/types/system"
+	"gotest.tools/v3/assert"
+	is "gotest.tools/v3/assert/cmp"
 )
 
 func TestLegacyFields(t *testing.T) {
@@ -31,3 +34,71 @@ func TestLegacyFields(t *testing.T) {
 		t.Errorf("legacy fields should contain %s: %s", expected, string(data))
 	}
 }
+
+// TestMarshalRegistryConfigLegacyFields verifies extra fields in the registry config
+// field in the info response are serialized if they are not empty.
+// This is used for backwards compatibility for API versions < 1.47.
+func TestMarshalRegistryConfigLegacyFields(t *testing.T) {
+	expected := []string{"AllowNondistributableArtifactsCIDRs", "AllowNondistributableArtifactsHostnames"}
+
+	tests := []struct {
+		name   string
+		info   *infoResponse
+		assert func(t *testing.T, data []byte, err error)
+	}{
+		{
+			name: "without legacy fields",
+			info: &infoResponse{
+				Info: &system.Info{},
+			},
+			assert: func(t *testing.T, data []byte, err error) {
+				assert.NilError(t, err)
+
+				var resp map[string]any
+				err = json.Unmarshal(data, &resp)
+				assert.NilError(t, err)
+
+				rc, ok := resp["RegistryConfig"]
+				assert.Check(t, ok)
+
+				for _, v := range expected {
+					assert.Check(t, !is.Contains(rc, v)().Success())
+				}
+			},
+		},
+		{
+			name: "with legacy fields",
+			info: &infoResponse{
+				Info: &system.Info{
+					RegistryConfig: &registry.ServiceConfig{
+						ExtraFields: map[string]any{
+							"AllowNondistributableArtifactsCIDRs":     json.RawMessage(nil),
+							"AllowNondistributableArtifactsHostnames": json.RawMessage(nil),
+						},
+					},
+				},
+			},
+			assert: func(t *testing.T, data []byte, err error) {
+				assert.NilError(t, err)
+
+				var resp map[string]any
+				err = json.Unmarshal(data, &resp)
+				assert.NilError(t, err)
+
+				rc, ok := resp["RegistryConfig"]
+				assert.Check(t, ok)
+
+				for _, v := range expected {
+					assert.Check(t, is.Contains(rc, v))
+				}
+			},
+		},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			data, err := json.MarshalIndent(tc.info, "", "  ")
+			tc.assert(t, data, err)
+		})
+	}
+}

vendor/github.com/moby/moby/api/types/registry/registry.go

@@ -17,23 +17,6 @@ type ServiceConfig struct {
 	ExtraFields map[string]any `json:"-"`
 }
 
-// MarshalJSON implements a custom marshaler to include legacy fields
-// in API responses.
-func (sc *ServiceConfig) MarshalJSON() ([]byte, error) {
-	type tmp ServiceConfig
-	base, err := json.Marshal((*tmp)(sc))
-	if err != nil {
-		return nil, err
-	}
-	var merged map[string]any
-	_ = json.Unmarshal(base, &merged)
-
-	for k, v := range sc.ExtraFields {
-		merged[k] = v
-	}
-	return json.Marshal(merged)
-}
-
 // NetIPNet is the net.IPNet type, which can be marshalled and
 // unmarshalled to JSON
 type NetIPNet net.IPNet