Fix NPE thrown from serializing/deserializing a structure that has map type with null values (#3138)

* Fix NPE thrown from serializing/deserializing a structure that has map type with null values

* fix checkstyle

Author: zoewangg

.changes/next-release/bugfix-AWSSDKforJavav2-edfb037.json

@@ -0,0 +1,6 @@
+{
+    "category": "AWS SDK for Java v2", 
+    "contributor": "", 
+    "type": "bugfix", 
+    "description": "Fix NPE thrown from serializing/deserializing a structure that has map type with null values"
+}

codegen/src/main/java/software/amazon/awssdk/codegen/poet/model/MemberCopierSpec.java

@@ -245,12 +245,14 @@ private String copyMethodBody(CodeBlock.Builder code, BuilderTransform builderTr
                 case BUILDER_TO_BUILDABLE:
                     String buildableOutput = variableSource.getNew("member");
                     TypeName buildableOutputType = typeName(inputMember, false, false, builderTransform, enumTransform);
-                    code.add("$T $N = $N.build();", buildableOutputType, buildableOutput, inputVariableName);
+                    code.add("$T $N = $N == null ? null : $N.build();", buildableOutputType, buildableOutput, inputVariableName,
+                             inputVariableName);
                     return buildableOutput;
                 case BUILDABLE_TO_BUILDER:
                     String builderOutput = variableSource.getNew("member");
                     TypeName builderOutputType = typeName(inputMember, false, false, builderTransform, enumTransform);
-                    code.add("$T $N = $N.toBuilder();", builderOutputType, builderOutput, inputVariableName);
+                    code.add("$T $N = $N == null ? null : $N.toBuilder();", builderOutputType, builderOutput, inputVariableName,
+                             inputVariableName);
                     return builderOutput;
                 default:
                     throw new IllegalStateException();

codegen/src/test/resources/software/amazon/awssdk/codegen/poet/model/listofmapofstringtostructcopier.java

@@ -55,7 +55,7 @@ static List<Map<String, SimpleStruct>> copyFromBuilder(
                 } else {
                     Map<String, SimpleStruct> modifiableMap = new LinkedHashMap<>();
                     entry.forEach((key, value) -> {
-                        SimpleStruct member = value.build();
+                        SimpleStruct member = value == null ? null : value.build();
                         modifiableMap.put(key, member);
                     });
                     map = Collections.unmodifiableMap(modifiableMap);
@@ -81,7 +81,7 @@ static List<Map<String, SimpleStruct.Builder>> copyToBuilder(
                 } else {
                     Map<String, SimpleStruct.Builder> modifiableMap = new LinkedHashMap<>();
                     entry.forEach((key, value) -> {
-                        SimpleStruct.Builder member = value.toBuilder();
+                        SimpleStruct.Builder member = value == null ? null : value.toBuilder();
                         modifiableMap.put(key, member);
                     });
                     map = Collections.unmodifiableMap(modifiableMap);

codegen/src/test/resources/software/amazon/awssdk/codegen/poet/model/listofsimplestructscopier.java

@@ -33,7 +33,7 @@ static List<SimpleStruct> copyFromBuilder(Collection<? extends SimpleStruct.Buil
         } else {
             List<SimpleStruct> modifiableList = new ArrayList<>();
             listOfSimpleStructsParam.forEach(entry -> {
-                SimpleStruct member = entry.build();
+                SimpleStruct member = entry == null ? null : entry.build();
                 modifiableList.add(member);
             });
             list = Collections.unmodifiableList(modifiableList);
@@ -48,7 +48,7 @@ static List<SimpleStruct.Builder> copyToBuilder(Collection<? extends SimpleStruc
         } else {
             List<SimpleStruct.Builder> modifiableList = new ArrayList<>();
             listOfSimpleStructsParam.forEach(entry -> {
-                SimpleStruct.Builder member = entry.toBuilder();
+                SimpleStruct.Builder member = entry == null ? null : entry.toBuilder();
                 modifiableList.add(member);
             });
             list = Collections.unmodifiableList(modifiableList);

codegen/src/test/resources/software/amazon/awssdk/codegen/poet/model/mapofenumtosimplestructcopier.java

@@ -32,7 +32,7 @@ static Map<String, SimpleStruct> copyFromBuilder(Map<String, ? extends SimpleStr
         } else {
             Map<String, SimpleStruct> modifiableMap = new LinkedHashMap<>();
             mapOfEnumToSimpleStructParam.forEach((key, value) -> {
-                SimpleStruct member = value.build();
+                SimpleStruct member = value == null ? null : value.build();
                 modifiableMap.put(key, member);
             });
             map = Collections.unmodifiableMap(modifiableMap);
@@ -47,7 +47,7 @@ static Map<String, SimpleStruct.Builder> copyToBuilder(Map<String, ? extends Sim
         } else {
             Map<String, SimpleStruct.Builder> modifiableMap = new LinkedHashMap<>();
             mapOfEnumToSimpleStructParam.forEach((key, value) -> {
-                SimpleStruct.Builder member = value.toBuilder();
+                SimpleStruct.Builder member = value == null ? null : value.toBuilder();
                 modifiableMap.put(key, member);
             });
             map = Collections.unmodifiableMap(modifiableMap);

codegen/src/test/resources/software/amazon/awssdk/codegen/poet/model/mapofstringtosimplestructcopier.java

@@ -32,7 +32,7 @@ static Map<String, SimpleStruct> copyFromBuilder(Map<String, ? extends SimpleStr
         } else {
             Map<String, SimpleStruct> modifiableMap = new LinkedHashMap<>();
             mapOfStringToSimpleStructParam.forEach((key, value) -> {
-                SimpleStruct member = value.build();
+                SimpleStruct member = value == null ? null : value.build();
                 modifiableMap.put(key, member);
             });
             map = Collections.unmodifiableMap(modifiableMap);
@@ -47,7 +47,7 @@ static Map<String, SimpleStruct.Builder> copyToBuilder(Map<String, ? extends Sim
         } else {
             Map<String, SimpleStruct.Builder> modifiableMap = new LinkedHashMap<>();
             mapOfStringToSimpleStructParam.forEach((key, value) -> {
-                SimpleStruct.Builder member = value.toBuilder();
+                SimpleStruct.Builder member = value == null ? null : value.toBuilder();
                 modifiableMap.put(key, member);
             });
             map = Collections.unmodifiableMap(modifiableMap);

codegen/src/test/resources/software/amazon/awssdk/codegen/poet/model/recursivelisttypecopier.java

@@ -33,7 +33,7 @@ static List<RecursiveStructType> copyFromBuilder(Collection<? extends RecursiveS
         } else {
             List<RecursiveStructType> modifiableList = new ArrayList<>();
             recursiveListTypeParam.forEach(entry -> {
-                RecursiveStructType member = entry.build();
+                RecursiveStructType member = entry == null ? null : entry.build();
                 modifiableList.add(member);
             });
             list = Collections.unmodifiableList(modifiableList);
@@ -48,7 +48,7 @@ static List<RecursiveStructType.Builder> copyToBuilder(Collection<? extends Recu
         } else {
             List<RecursiveStructType.Builder> modifiableList = new ArrayList<>();
             recursiveListTypeParam.forEach(entry -> {
-                RecursiveStructType.Builder member = entry.toBuilder();
+                RecursiveStructType.Builder member = entry == null ? null : entry.toBuilder();
                 modifiableList.add(member);
             });
             list = Collections.unmodifiableList(modifiableList);

codegen/src/test/resources/software/amazon/awssdk/codegen/poet/model/recursivemaptypecopier.java

@@ -33,7 +33,7 @@ static Map<String, RecursiveStructType> copyFromBuilder(
         } else {
             Map<String, RecursiveStructType> modifiableMap = new LinkedHashMap<>();
             recursiveMapTypeParam.forEach((key, value) -> {
-                RecursiveStructType member = value.build();
+                RecursiveStructType member = value == null ? null : value.build();
                 modifiableMap.put(key, member);
             });
             map = Collections.unmodifiableMap(modifiableMap);
@@ -48,7 +48,7 @@ static Map<String, RecursiveStructType.Builder> copyToBuilder(Map<String, ? exte
         } else {
             Map<String, RecursiveStructType.Builder> modifiableMap = new LinkedHashMap<>();
             recursiveMapTypeParam.forEach((key, value) -> {
-                RecursiveStructType.Builder member = value.toBuilder();
+                RecursiveStructType.Builder member = value == null ? null : value.toBuilder();
                 modifiableMap.put(key, member);
             });
             map = Collections.unmodifiableMap(modifiableMap);

test/codegen-generated-classes-test/src/test/java/software/amazon/awssdk/services/ModelSerializationTest.java

@@ -29,6 +29,8 @@
 import com.fasterxml.jackson.databind.module.SimpleModule;
 import java.io.IOException;
 import java.time.Instant;
+import java.util.HashMap;
+import java.util.Map;
 import org.junit.jupiter.api.Test;
 import software.amazon.awssdk.core.SdkBytes;
 import software.amazon.awssdk.services.protocolrestjson.model.AllTypesRequest;
@@ -48,6 +50,14 @@ public void jacksonSerializationWorksForEmptyRequestObjects() throws IOException
         validateJacksonSerialization(AllTypesRequest.builder().build());
     }
 
+    @Test
+    public void jacksonSerialization_mapWithNullValue_shouldWork() throws IOException {
+        Map<String, SimpleStruct> mapOfStringToStruct = new HashMap<>();
+        mapOfStringToStruct.put("test1", null);
+        mapOfStringToStruct.put("test2", null);
+        validateJacksonSerialization(AllTypesRequest.builder().mapOfStringToStruct(mapOfStringToStruct).build());
+    }
+
     @Test
     public void jacksonSerializationWorksForPopulatedRequestModels() throws IOException {
         SdkBytes blob = SdkBytes.fromUtf8String("foo");