Fix WeChat Pay profit-sharing callback signature verification line separator inconsistency

[Copilot]

Problem

The ProfitSharingServiceImpl.verifyNotifySign() method was using platform-specific line separators (%n) while the base implementation uses LF (\n), causing signature verification failures in WeChat Pay Service Provider Mode profit-sharing callbacks.

Root Cause

WeChat Pay signature verification requires consistent use of LF (\n) as line separator. The profit-sharing service was using:

String beforeSign = String.format("%s%n%s%n%s%n", header.getTimeStamp(), header.getNonce(), data);

While the base implementation correctly uses:

String beforeSign = String.format("%s\n%s\n%s\n", header.getTimeStamp(), header.getNonce(), data);

The %n format specifier produces platform-specific line separators (LF on Unix/Linux, CRLF on Windows), causing signature verification to fail with "非法请求，头部信息验证失败" (Illegal request, header verification failed) errors.

Solution

1. Fixed line separator format: Changed from %n to \n to ensure consistent LF line separators across all platforms
2. Added signature test traffic detection: Added check for WECHATPAY/SIGNTEST/ prefix to properly handle WeChat Pay signature test traffic
3. Added proper exception handling: Imported and used WxSignTestException for signature test scenarios

Changes Made

• Updated ProfitSharingServiceImpl.verifyNotifySign() to use \n instead of %n
• Added signature test traffic detection with proper exception handling
• Added missing import for WxSignTestException

This ensures consistency with other service implementations and resolves signature verification failures in profit-sharing callbacks.

Fixes #3634.

---

💡 You can make Copilot smarter by setting up custom instructions, customizing its development environment and configuring Model Context Protocol (MCP) servers. Learn more Copilot coding agent tips in the docs.