fix: task params nil params panic (#25697)

Co-authored-by: Qiu Jian <qiujian@yunionyun.com>

go.mod

@@ -12,6 +12,7 @@ require (
 	github.com/aws/aws-sdk-go-v2/credentials v1.18.16
 	github.com/aws/aws-sdk-go-v2/service/s3 v1.88.4
 	github.com/aws/smithy-go v1.24.2
+	github.com/beevik/etree v1.1.0
 	github.com/benbjohnson/clock v1.0.0
 	github.com/bitly/go-simplejson v0.5.0
 	github.com/c-bata/go-prompt v0.2.4
@@ -51,6 +52,7 @@ require (
 	github.com/lestrrat-go/jwx v1.2.25
 	github.com/lestrrat/go-jwx v0.0.0-20180221005942-b7d4802280ae
 	github.com/libvirt/libvirt-go-xml v5.2.0+incompatible
+	github.com/ma314smith/signedxml v0.0.0-20210628192057-abc5b481ae1c
 	github.com/mark3labs/mcp-go v0.48.0
 	github.com/mattn/go-sqlite3 v1.14.19
 	github.com/mdlayher/arp v0.0.0-20190313224443-98a83c8a2717
@@ -114,7 +116,7 @@ require (
 	moul.io/http2curl/v2 v2.3.0
 	yunion.io/x/cloudmux v0.3.10-0-alpha.1.0.20260904120449-8aa2a5d6ba7a
 	yunion.io/x/executor v0.0.0-20260312022053-f538abd2b005
-	yunion.io/x/jsonutils v1.0.1-0.20260715075349-615cfb44ff7c
+	yunion.io/x/jsonutils v1.0.1-0.20260916031541-8e0c8de6eb2e
 	yunion.io/x/log v1.0.1-0.20240305175729-7cf2d6cd5a91
 	yunion.io/x/ovsdb v0.0.0-20230306173834-f164f413a900
 	yunion.io/x/pkg v1.10.4-0.20260722094907-0da70a14584f
@@ -190,7 +192,6 @@ require (
 	github.com/aws/aws-sdk-go-v2/service/sts v1.38.6 // indirect
 	github.com/bahlo/generic-list-go v0.2.0 // indirect
 	github.com/basgys/goxml2json v1.1.1-0.20181031222924-996d9fc8d313 // indirect
-	github.com/beevik/etree v1.1.0 // indirect
 	github.com/benbjohnson/immutable v0.3.0 // indirect
 	github.com/beorn7/perks v1.0.1 // indirect
 	github.com/bits-and-blooms/bitset v1.2.2 // indirect
@@ -287,7 +288,6 @@ require (
 	github.com/lestrrat-go/option v1.0.0 // indirect
 	github.com/lestrrat/go-pdebug v0.0.0-20180220043741-569c97477ae8 // indirect
 	github.com/lufia/plan9stats v0.0.0-20220913051719-115f729f3c8c // indirect
-	github.com/ma314smith/signedxml v0.0.0-20210628192057-abc5b481ae1c // indirect
 	github.com/mailru/easyjson v0.7.7 // indirect
 	github.com/mattn/go-colorable v0.1.11 // indirect
 	github.com/mattn/go-isatty v0.0.16 // indirect

go.sum

@@ -1782,8 +1782,8 @@ yunion.io/x/cloudmux v0.3.10-0-alpha.1.0.20260904120449-8aa2a5d6ba7a/go.mod h1:F
 yunion.io/x/executor v0.0.0-20260312022053-f538abd2b005 h1:3sWwcjGXGjG9mLBWa7AyLq+QSi0udTAx21pfVQRFMBE=
 yunion.io/x/executor v0.0.0-20260312022053-f538abd2b005/go.mod h1:Uxuou9WQIeJXNpy7t2fPLL0BYLvLiMvGQwY7Qc6aSws=
 yunion.io/x/jsonutils v0.0.0-20190625054549-a964e1e8a051/go.mod h1:4N0/RVzsYL3kH3WE/H1BjUQdFiWu50JGCFQuuy+Z634=
-yunion.io/x/jsonutils v1.0.1-0.20260715075349-615cfb44ff7c h1:FthZM1upg4/yF4vmYheo/J7a738sGPjWPKk5kY88sH0=
-yunion.io/x/jsonutils v1.0.1-0.20260715075349-615cfb44ff7c/go.mod h1:VK4Z93dgiKgAijcSqbMKmGaBMJuHulR16Hz4K015ZPo=
+yunion.io/x/jsonutils v1.0.1-0.20260916031541-8e0c8de6eb2e h1:0M7SVtySPc+zyHm4BqJ5XZQx2dDL2fwHccR/QZrbUMg=
+yunion.io/x/jsonutils v1.0.1-0.20260916031541-8e0c8de6eb2e/go.mod h1:VK4Z93dgiKgAijcSqbMKmGaBMJuHulR16Hz4K015ZPo=
 yunion.io/x/log v0.0.0-20190514041436-04ce53b17c6b/go.mod h1:+gauLs73omeJAPlsXcevLsJLKixV+sR/E7WSYTSx1fE=
 yunion.io/x/log v0.0.0-20190629062853-9f6483a7103d/go.mod h1:LC6f/4FozL0iaAbnFt2eDX9jlsyo3WiOUPm03d7+U4U=
 yunion.io/x/log v1.0.1-0.20240305175729-7cf2d6cd5a91 h1:inY5o3LDa/zgsIZuPN0HmpzKIsu/lLgsBmMttuDPGj4=

pkg/cloudcommon/db/taskman/tasks.go

@@ -951,7 +951,22 @@ func (task *STask) ClearPendingUsage(index int) error {
 }
 
 func (task *STask) GetParams() *jsonutils.JSONDict {
-	return task.Params
+	result := jsonutils.NewDict()
+	if task.Params == nil {
+		return result
+	}
+	copied := task.Params.DeepCopy()
+	copyParams, ok := copied.(*jsonutils.JSONDict)
+	if !ok || copyParams == nil {
+		return result
+	}
+	paramsJsonMap, _ := copyParams.GetMap()
+	for k, v := range paramsJsonMap {
+		if !strings.HasPrefix(k, "__") {
+			result.Set(k, v)
+		}
+	}
+	return result
 }
 
 func (task *STask) GetUserCred() mcclient.TokenCredential {

pkg/cloudcommon/db/taskman/tasks_test.go

@@ -0,0 +1,144 @@
+// Copyright 2019 Yunion
+//
+// 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 taskman
+
+import (
+	"testing"
+
+	"yunion.io/x/jsonutils"
+)
+
+func TestSTaskGetParams(t *testing.T) {
+	newParams := func(pairs map[string]jsonutils.JSONObject) *jsonutils.JSONDict {
+		params := jsonutils.NewDict()
+		for k, v := range pairs {
+			params.Set(k, v)
+		}
+		return params
+	}
+
+	nested := jsonutils.NewDict()
+	nested.Set("ip", jsonutils.NewString("10.0.0.1"))
+	stages := jsonutils.NewArray(
+		jsonutils.NewDict(),
+		jsonutils.NewString("on_init"),
+	)
+
+	cases := []struct {
+		name   string
+		params *jsonutils.JSONDict
+		want   *jsonutils.JSONDict
+	}{
+		{
+			name:   "nil_params",
+			params: nil,
+			want:   jsonutils.NewDict(),
+		},
+		{
+			name:   "empty_params",
+			params: jsonutils.NewDict(),
+			want:   jsonutils.NewDict(),
+		},
+		{
+			name: "keep_public_keys",
+			params: newParams(map[string]jsonutils.JSONObject{
+				"parent_task_id": jsonutils.NewString("task-1"),
+				"auto_start":     jsonutils.JSONTrue,
+			}),
+			want: newParams(map[string]jsonutils.JSONObject{
+				"parent_task_id": jsonutils.NewString("task-1"),
+				"auto_start":     jsonutils.JSONTrue,
+			}),
+		},
+		{
+			name: "drop_internal_keys",
+			params: newParams(map[string]jsonutils.JSONObject{
+				"__stages":                stages,
+				"__pending_usage__":       jsonutils.NewDict(),
+				"__request_context":       jsonutils.NewDict(),
+				"__parent_task_notifyurl": jsonutils.NewString("http://notify"),
+			}),
+			want: jsonutils.NewDict(),
+		},
+		{
+			name: "mixed_keys",
+			params: newParams(map[string]jsonutils.JSONObject{
+				"desc":     nested,
+				"__stages": stages,
+				"_private": jsonutils.NewString("keep"),
+				"__":       jsonutils.NewString("drop"),
+				"guest_id": jsonutils.NewString("g-1"),
+			}),
+			want: newParams(map[string]jsonutils.JSONObject{
+				"desc":     nested,
+				"_private": jsonutils.NewString("keep"),
+				"guest_id": jsonutils.NewString("g-1"),
+			}),
+		},
+	}
+
+	for _, c := range cases {
+		c := c
+		t.Run(c.name, func(t *testing.T) {
+			task := &STask{}
+			task.Params = c.params
+			got := task.GetParams()
+			if got == nil {
+				t.Fatal("GetParams() returned nil, want empty dict")
+			}
+			if !got.Equals(c.want) {
+				t.Fatalf("GetParams() = %s, want %s", got, c.want)
+			}
+		})
+	}
+}
+
+func TestSTaskGetParamsDoesNotMutateOriginal(t *testing.T) {
+	orig := jsonutils.NewDict()
+	orig.Set("guest_id", jsonutils.NewString("g-1"))
+	orig.Set("__stages", jsonutils.NewArray(jsonutils.NewString("on_init")))
+	nested := jsonutils.NewDict()
+	nested.Set("ip", jsonutils.NewString("10.0.0.1"))
+	orig.Set("desc", nested)
+
+	task := &STask{STaskBase: STaskBase{Params: orig}}
+	got := task.GetParams()
+	got.Set("guest_id", jsonutils.NewString("g-2"))
+	got.Set("extra", jsonutils.JSONTrue)
+	desc, err := got.Get("desc")
+	if err != nil {
+		t.Fatalf("get desc: %v", err)
+	}
+	descDict, ok := desc.(*jsonutils.JSONDict)
+	if !ok {
+		t.Fatalf("desc type %T, want *jsonutils.JSONDict", desc)
+	}
+	descDict.Set("ip", jsonutils.NewString("10.0.0.2"))
+
+	if got.Contains("__stages") {
+		t.Fatal("GetParams() leaked internal key __stages")
+	}
+	guestId, _ := orig.GetString("guest_id")
+	if guestId != "g-1" {
+		t.Fatalf("original guest_id = %s, want g-1", guestId)
+	}
+	if !orig.Contains("__stages") {
+		t.Fatal("original __stages was removed")
+	}
+	origIp, _ := orig.GetString("desc", "ip")
+	if origIp != "10.0.0.1" {
+		t.Fatalf("original nested ip = %s, want 10.0.0.1", origIp)
+	}
+}

pkg/compute/guestdrivers/baremetals.go

@@ -356,6 +356,7 @@ func (self *SBaremetalGuestDriver) RequestStartOnHost(ctx context.Context, guest
 	if params.Length() > 0 {
 		config.Add(params, "params")
 	}
+	log.Debugf("RequestStartOnHost config: %s", config.String())
 	headers := task.GetTaskRequestHeader()
 	url := fmt.Sprintf("/baremetals/%s/servers/%s/start", host.Id, guest.Id)
 	_, err := host.BaremetalSyncRequest(ctx, "POST", url, headers, config)

vendor/modules.txt

@@ -2672,7 +2672,7 @@ yunion.io/x/cloudmux/pkg/multicloud/zstack/provider
 yunion.io/x/executor/apis
 yunion.io/x/executor/client
 yunion.io/x/executor/server
-# yunion.io/x/jsonutils v1.0.1-0.20260715075349-615cfb44ff7c
+# yunion.io/x/jsonutils v1.0.1-0.20260916031541-8e0c8de6eb2e
 ## explicit; go 1.18
 yunion.io/x/jsonutils
 # yunion.io/x/log v1.0.1-0.20240305175729-7cf2d6cd5a91

vendor/yunion.io/x/jsonutils/access.go

@@ -20,10 +20,18 @@ import (
 	"time"
 
 	"yunion.io/x/pkg/errors"
+	"yunion.io/x/pkg/gotypes"
 	"yunion.io/x/pkg/sortedmap"
 	"yunion.io/x/pkg/util/timeutils"
 )
 
+func normalizeJSONObject(obj JSONObject) JSONObject {
+	if gotypes.IsNil(obj) {
+		return JSONNull
+	}
+	return obj
+}
+
 type JSONPair struct {
 	key string
 	val JSONObject
@@ -40,7 +48,7 @@ func NewDict(objs ...JSONPair) *JSONDict {
 func NewArray(objs ...JSONObject) *JSONArray {
 	arr := JSONArray{data: make([]JSONObject, 0, len(objs))}
 	for _, o := range objs {
-		arr.data = append(arr.data, o)
+		arr.data = append(arr.data, normalizeJSONObject(o))
 	}
 	return &arr
 }
@@ -74,7 +82,7 @@ func NewBool(val bool) *JSONBool {
 }
 
 func (this *JSONDict) Set(key string, value JSONObject) {
-	this.data = sortedmap.Add(this.data, key, value)
+	this.data = sortedmap.Add(this.data, key, normalizeJSONObject(value))
 }
 
 func (this *JSONDict) Remove(key string) bool {
@@ -130,12 +138,12 @@ func (this *JSONDict) Add(o JSONObject, keys ...string) error {
 }
 
 func (this *JSONArray) SetAt(idx int, obj JSONObject) {
-	this.data[idx] = obj
+	this.data[idx] = normalizeJSONObject(obj)
 }
 
 func (this *JSONArray) Add(objs ...JSONObject) {
 	for _, o := range objs {
-		this.data = append(this.data, o)
+		this.data = append(this.data, normalizeJSONObject(o))
 	}
 }
 

vendor/yunion.io/x/jsonutils/consts.go

@@ -20,4 +20,7 @@ import (
 
 const (
 	TAG_DEPRECATED_BY = reflectutils.TAG_DEPRECATED_BY
+
+	// maxParseDepth is the maximum nesting level accepted by the parser
+	maxParseDepth = 10000
 )

vendor/yunion.io/x/jsonutils/equals.go

@@ -15,6 +15,7 @@
 package jsonutils
 
 import (
+	"yunion.io/x/pkg/gotypes"
 	"yunion.io/x/pkg/sortedmap"
 )
 
@@ -51,7 +52,14 @@ func (arr *JSONArray) Equals(json JSONObject) bool {
 		return false
 	}
 	for i, v := range arr.data {
-		if !v.Equals(arr2.data[i]) {
+		oth := arr2.data[i]
+		if gotypes.IsNil(v) || gotypes.IsNil(oth) {
+			if gotypes.IsNil(v) != gotypes.IsNil(oth) {
+				return false
+			}
+			continue
+		}
+		if !v.Equals(oth) {
 			return false
 		}
 	}

vendor/yunion.io/x/jsonutils/errors.go

@@ -26,6 +26,10 @@ const (
 	ErrInvalidHex  = errors.Error("invalid hex")
 	ErrInvalidRune = errors.Error("invalid 4 byte rune")
 
+	ErrInvalidNodeId   = errors.Error("invalid node id")
+	ErrDuplicateNodeId = errors.Error("duplicate node id")
+	ErrNestedTooDeep   = errors.Error("json nested too deep")
+
 	ErrTypeMismatch         = errors.Error("unmarshal type mismatch")
 	ErrArrayLengthMismatch  = errors.Error("unmarshal array length mismatch")
 	ErrInterfaceUnsupported = errors.Error("do not known how to deserialize json into this interface type")

vendor/yunion.io/x/jsonutils/interface.go

@@ -15,6 +15,7 @@
 package jsonutils
 
 import (
+	"yunion.io/x/pkg/gotypes"
 	"yunion.io/x/pkg/sortedmap"
 )
 
@@ -41,6 +42,10 @@ func (self *JSONString) Interface() interface{} {
 func (self *JSONArray) Interface() interface{} {
 	ret := make([]interface{}, len(self.data))
 	for i := 0; i < len(self.data); i += 1 {
+		if gotypes.IsNil(self.data[i]) {
+			ret[i] = nil
+			continue
+		}
 		ret[i] = self.data[i].Interface()
 	}
 	return ret
@@ -51,7 +56,12 @@ func (self *JSONDict) Interface() interface{} {
 
 	for iter := sortedmap.NewIterator(self.data); iter.HasMore(); iter.Next() {
 		k, v := iter.Get()
-		mapping[k] = v.(JSONObject).Interface()
+		jo, _ := v.(JSONObject)
+		if gotypes.IsNil(jo) {
+			mapping[k] = nil
+			continue
+		}
+		mapping[k] = jo.Interface()
 	}
 
 	return mapping

vendor/yunion.io/x/jsonutils/jsonutils.go

@@ -259,7 +259,7 @@ func (s *sJsonParseSession) parseJSONValue(str []byte, offset int) (JSONObject,
 		return nil, i, errors.Wrap(e, "parseString")
 	} else if quote {
 		return &JSONString{data: val}, i, nil
-	} else if val[0] == '<' && val[len(val)-1] == '>' {
+	} else if len(val) > 1 && val[0] == '<' && val[len(val)-1] == '>' {
 		// Pointer <nnnn>
 		val = val[1 : len(val)-1]
 		ival, err := strconv.ParseInt(val, 10, 64)
@@ -476,7 +476,11 @@ func (s *sJsonParseSession) parseDict(str []byte, offset int) (sortedmap.SSorted
 		}
 		if key == jsonPointerKey {
 			// node id
-			nodeId = int(val.(*JSONInt).data)
+			jval, ok := val.(*JSONInt)
+			if !ok {
+				return smap, i, nodeId, errors.Wrap(ErrInvalidNodeId, jsonPointerKey)
+			}
+			nodeId = int(jval.data)
 		} else {
 			smap = sortedmap.Add(smap, key, val)
 		}
@@ -552,12 +556,20 @@ func (s *sJsonParseSession) parseArray(str []byte, offset int) ([]JSONObject, in
 }
 
 func (this *JSONDict) parse(s *sJsonParseSession, str []byte, offset int) (int, error) {
+	e := s.enter()
+	if e != nil {
+		return offset, errors.Wrap(e, "enter")
+	}
+	defer s.leave()
 	smap, i, nodeId, e := s.parseDict(str, offset)
 	if e == nil {
 		this.nodeId = nodeId
 		this.data = smap
 		if this.nodeId > 0 {
-			s.saveNode(nodeId, this)
+			e = s.saveNode(nodeId, this)
+			if e != nil {
+				return i, errors.Wrap(e, "saveNode")
+			}
 		}
 		return i, nil
 	}
@@ -594,14 +606,19 @@ func (this *JSONDict) prettyString(level int) string {
 		buffer.WriteByte('"')
 		buffer.WriteString(k)
 		buffer.WriteString("\":")
-		_, okdict := v.(*JSONDict)
-		_, okarray := v.(*JSONArray)
-		if okdict || okarray {
-			buffer.WriteByte('\n')
-			buffer.WriteString(v.prettyString(level + 2))
-		} else {
+		if gotypes.IsNil(v) {
 			buffer.WriteByte(' ')
-			buffer.WriteString(v.String())
+			buffer.WriteString("null")
+		} else {
+			_, okdict := v.(*JSONDict)
+			_, okarray := v.(*JSONArray)
+			if okdict || okarray {
+				buffer.WriteByte('\n')
+				buffer.WriteString(v.prettyString(level + 2))
+			} else {
+				buffer.WriteByte(' ')
+				buffer.WriteString(v.String())
+			}
 		}
 		idx++
 	}
@@ -614,6 +631,11 @@ func (this *JSONDict) prettyString(level int) string {
 }
 
 func (this *JSONArray) parse(s *sJsonParseSession, str []byte, offset int) (int, error) {
+	e := s.enter()
+	if e != nil {
+		return offset, errors.Wrap(e, "enter")
+	}
+	defer s.leave()
 	val, i, e := s.parseArray(str, offset)
 	if e == nil {
 		this.data = val
@@ -639,7 +661,12 @@ func (this *JSONArray) prettyString(level int) string {
 			buffer.WriteString(",")
 		}
 		buffer.WriteByte('\n')
-		buffer.WriteString(v.prettyString(level + 1))
+		if gotypes.IsNil(v) {
+			buffer.WriteString(tab)
+			buffer.WriteString("  null")
+		} else {
+			buffer.WriteString(v.prettyString(level + 1))
+		}
 	}
 	if len(this.data) > 0 {
 		buffer.WriteByte('\n')

vendor/yunion.io/x/jsonutils/marshal.go

@@ -48,7 +48,7 @@ func (s *sJsonMarshalSession) marshalSlice(val reflect.Value, info *reflectutils
 	objs := make([]JSONObject, 0)
 	for i := 0; i < val.Len(); i += 1 {
 		val := s.marshalValue(val.Index(i), nil, omitEmpty)
-		if val != nil {
+		if !gotypes.IsNil(val) {
 			objs = append(objs, val)
 		}
 	}
@@ -84,7 +84,7 @@ func (s *sJsonMarshalSession) marshalMap(val reflect.Value, info *reflectutils.S
 	for i := 0; i < len(keys); i += 1 {
 		key := keys[i]
 		val := s.marshalValue(val.MapIndex(key), nil, omitEmpty)
-		if val != nil {
+		if !gotypes.IsNil(val) {
 			objPairs = append(objPairs, JSONPair{key: fmt.Sprintf("%s", key), val: val})
 		}
 	}
@@ -133,7 +133,7 @@ func (s *sJsonMarshalSession) struct2JSONPairs(val reflect.Value, omitEmpty bool
 			continue
 		}
 		val := s.marshalValue(fields[i].Value, jsonInfo, omitEmpty)
-		if val != nil {
+		if !gotypes.IsNil(val) {
 			objPair := JSONPair{key: key, val: val}
 			objPairs = append(objPairs, objPair)
 		}

vendor/yunion.io/x/jsonutils/parse_session.go

@@ -15,7 +15,7 @@
 package jsonutils
 
 import (
-	"fmt"
+	"yunion.io/x/pkg/errors"
 )
 
 type sNodeReferer struct {
@@ -25,6 +25,9 @@ type sNodeReferer struct {
 
 type sJsonParseSession struct {
 	objectMap map[int]*sNodeReferer
+
+	// depth is the current nesting level of the object/array being parsed
+	depth int
 }
 
 func newJsonParseSession() *sJsonParseSession {
@@ -33,6 +36,20 @@ func newJsonParseSession() *sJsonParseSession {
 	}
 }
 
+// enter records entering one more nesting level, it fails if the nesting
+// level exceeds maxParseDepth
+func (s *sJsonParseSession) enter() error {
+	if s.depth >= maxParseDepth {
+		return ErrNestedTooDeep
+	}
+	s.depth++
+	return nil
+}
+
+func (s *sJsonParseSession) leave() {
+	s.depth--
+}
+
 func (s *sJsonParseSession) saveReferer(nodeId int, ptr *sJSONPointer) {
 	if nr, ok := s.objectMap[nodeId]; ok {
 		nr.pointers = append(nr.pointers, ptr)
@@ -43,10 +60,10 @@ func (s *sJsonParseSession) saveReferer(nodeId int, ptr *sJSONPointer) {
 	}
 }
 
-func (s *sJsonParseSession) saveNode(nodeId int, node JSONObject) {
+func (s *sJsonParseSession) saveNode(nodeId int, node JSONObject) error {
 	if nr, ok := s.objectMap[nodeId]; ok {
 		if nr.node != nil {
-			panic(fmt.Sprintf("nodeId %d alreayd exists: %s != %s", nodeId, nr.node, node))
+			return errors.Wrapf(ErrDuplicateNodeId, "node id %d", nodeId)
 		} else {
 			nr.node = node
 		}
@@ -56,4 +73,5 @@ func (s *sJsonParseSession) saveNode(nodeId int, node JSONObject) {
 			pointers: nil,
 		}
 	}
+	return nil
 }

vendor/yunion.io/x/jsonutils/write.go

@@ -18,9 +18,18 @@ import (
 	"fmt"
 	"strings"
 
+	"yunion.io/x/pkg/gotypes"
 	"yunion.io/x/pkg/sortedmap"
 )
 
+func writeJSONObject(sb *strings.Builder, v JSONObject) {
+	if gotypes.IsNil(v) {
+		sb.WriteString("null")
+		return
+	}
+	v.buildString(sb)
+}
+
 type writeSource interface {
 	buildString(sb *strings.Builder)
 }
@@ -46,6 +55,10 @@ func (this *JSONBool) buildString(sb *strings.Builder) {
 }
 
 func (this *JSONDict) buildString(sb *strings.Builder) {
+	if this == nil {
+		sb.WriteString("null")
+		return
+	}
 	sb.WriteByte('{')
 	var idx = 0
 	if this.nodeId > 0 {
@@ -63,19 +76,23 @@ func (this *JSONDict) buildString(sb *strings.Builder) {
 		sb.WriteString(quoteString(k))
 		sb.WriteByte(':')
 
-		v.buildString(sb)
+		writeJSONObject(sb, v)
 		idx++
 	}
 	sb.WriteByte('}')
 }
 
 func (this *JSONArray) buildString(sb *strings.Builder) {
+	if this == nil {
+		sb.WriteString("null")
+		return
+	}
 	sb.WriteByte('[')
 	for idx, v := range this.data {
 		if idx > 0 {
 			sb.WriteByte(',')
 		}
-		v.buildString(sb)
+		writeJSONObject(sb, v)
 	}
 	sb.WriteByte(']')
 }