C#: Eliminate payload extraction duplication, fix GetMsgId behavior, and correct XML comment formatting

[Copilot]

C# code generator had three issues: payload extraction logic (~15 lines) repeated in every message's Deserialize(FrameMsgInfo), messages without msgid returned 0 from GetMsgId(), and multi-line comments generated separate <summary> tags per line.

Changes

Centralized payload extraction

• Added ExtractPayload() method to FrameMsgInfo struct handling offset/length edge cases with bounds validation
• Reduced generated code from ~15 lines to ~6 lines per message

GetMsgId() behavior

• Messages without msgid now throw NotSupportedException with clear error message instead of returning 0
• Satisfies interface requirements while preventing ambiguous 0 return value

XML comment formatting

• Added format_xml_summary() helper to generate proper single-block XML documentation
• Fixed enum, message, field, and enum value comment generation

Example

Before:

public static Message Deserialize(FrameMsgInfo frameInfo) {
    if (frameInfo.MsgData == null) return new Message();
    byte[] payload;
    if (frameInfo.MsgDataOffset > 0) {
        payload = new byte[frameInfo.MsgLen];
        Array.Copy(frameInfo.MsgData, frameInfo.MsgDataOffset, payload, 0, frameInfo.MsgLen);
    } else {
        payload = frameInfo.MsgData;
    }
    return Deserialize(payload);
}

/// <summary>
/// Line 1
/// </summary>
/// <summary>
/// Line 2
/// </summary>

After:

public static Message Deserialize(FrameMsgInfo frameInfo) {
    if (frameInfo.MsgData == null) return new Message();
    return Deserialize(frameInfo.ExtractPayload());
}

/// <summary>
/// Line 1
/// Line 2
/// </summary>

Original prompt

---

This section details on the original issue you should resolve

<issue_title>C# has a few improvements</issue_title>
<issue_description>// Currently repeated in every message class
if (frameInfo.MsgDataOffset > 0)
{
payload = new byte[frameInfo.MsgLen];
Array.Copy(frameInfo.MsgData, frameInfo.MsgDataOffset, payload, 0, frameInfo.MsgLen);
}

GetMsgId() returns 0 for msgs without a msg_id. Instead these messages shouldn't have this function available or some other pattern</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes C# has a few improvements #261

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[rijesha]

@copilot are there other places in the c# generated code where ///

is not handled correctly

[Copilot]

@copilot are there other places in the c# generated code where ///

is not handled correctly

Your comment appears to be cut off. Could you please complete your question?

I noticed there are multiple places in the C# generator where XML documentation comments (///) might have issues:

1. Multi-line comments get multiple <summary> tags - Currently, each comment line gets wrapped in its own <summary> tag instead of all lines being inside a single <summary> block
2. Similar patterns in enum, message, and field comments

Are you asking about:

• Fixing the XML comment formatting for multi-line comments?
• Other code duplication patterns similar to the payload extraction?
• Something else?

Please let me know so I can address your concern properly.