[BUG] openai ChatRequestUserMessage deserialization loses internal state

[fairjm]

Describe the bug ChatRequestUserMessage loses its internal state during deserialization. The following fields are set to null:

    private final String stringContent;

    private final List<ChatMessageContentItem> chatMessageContentItems;

When these fields are null, subsequent requests fail.

To Reproduce

    @Test
    public void test() throws IOException {
        String userMessage = """
                    {
                      "role": "user",
                      "content": "this is test message"
                    }
                """;

        ChatRequestUserMessage u = BinaryData.fromString(userMessage).toObject(new TypeReference<>() {
        });
        System.out.println(u.toJsonString());
    }

it will output:

{"role":"user"}

Code Snippet Add the code snippet that causes the issue.

Expected behavior

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Setup (please complete the following information):

• OS: windows
• IDE: IntelliJ
• Library/Libraries: com.azure:azure-ai-openai:1.0.0-beta.12
• Java version: 21

If you suspect a dependency version mismatch (e.g. you see NoClassDefFoundError, NoSuchMethodError or similar), please check out Troubleshoot dependency version conflict article first. If it doesn't provide solution for the problem, please provide:

• verbose dependency tree (mvn dependency:tree -Dverbose)
• exception message, full stack trace, and any available logs

Additional context

    @Override
    public JsonWriter toJson(JsonWriter jsonWriter) throws IOException {
        jsonWriter.writeStartObject();
        jsonWriter.writeStringField("role", this.role == null ? null : this.role.toString());
        if (stringContent != null) {
            jsonWriter.writeStringField("content", stringContent);
        } else if (chatMessageContentItems != null) {
            jsonWriter.writeArrayField("content", chatMessageContentItems, JsonWriter::writeJson);
        }
        //  or set the content back here？👉
        jsonWriter.writeStringField("name", this.name);
        return jsonWriter.writeEndObject();
    }

    public static ChatRequestUserMessage fromJson(JsonReader jsonReader) throws IOException {
        return jsonReader.readObject(reader -> {
            BinaryData content = null;
            ChatRole role = ChatRole.USER;
            String name = null;
            while (reader.nextToken() != JsonToken.END_OBJECT) {
                String fieldName = reader.getFieldName();
                reader.nextToken();
                if ("content".equals(fieldName)) {

                    // here 👇 forget to set the stringContent or chatMessageContentItems
                    if (reader.currentToken() == JsonToken.STRING) {
                        content = BinaryData.fromString(reader.getString());
                    } else if (reader.currentToken() == JsonToken.START_ARRAY) {
                        content = BinaryData.fromObject(
                            reader.readArray(arrayReader -> arrayReader.readObject(ChatMessageContentItem::fromJson)));
                    } else {
                        throw new IllegalStateException("Unexpected 'content' type found when deserializing"
                            + " ChatRequestUserMessage JSON object: " + reader.currentToken());
                    }
                } else if ("role".equals(fieldName)) {
                    role = ChatRole.fromString(reader.getString());
                } else if ("name".equals(fieldName)) {
                    name = reader.getString();
                } else {
                    reader.skipChildren();
                }
            }
            ChatRequestUserMessage deserializedChatRequestUserMessage = new ChatRequestUserMessage(content);
            deserializedChatRequestUserMessage.role = role;
            deserializedChatRequestUserMessage.name = name;
            return deserializedChatRequestUserMessage;
        });

During serialization, the internal stringContent and chatMessageContentItems fields are used. However, during deserialization, these internal states are not set properly. As a result, after one round of deserialization and serialization, the content is completely lost. This bug has existed for a long time.

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• [ ] Bug Description Added
• [ ] Repro Steps Added
• [ ] Setup information Added

[fairjm]

I've noticed that ChatRequestSystemMessage, ChatRequestAssistantMessage and other similar message types all lose their internal state during deserialization. Is the API design of ChatRequest messages not intended for deserialization?

[alzimmermsft]

Thanks for reporting this @fairjm, @mssfang or @jpalvarezl could you looking into this and response