Fix asynchronous WUA methods (BeginSearch, BeginDownload, BeginInstall)

[wisper-sabrina]

The asynchronous WUA methods (BeginSearch, BeginDownload, BeginInstall) require a non-NULL IUnknown* callback argument. Passing NULL (VT_NULL) makes them fail with DISP_E_TYPEMISMATCH (0x80020005), so I fixed the functions

[gemini-code-assist]

Code Review

This pull request introduces a dummy callback mechanism (newNoopDispatch) in a new file olecallback.go to prevent Windows Update Agent (WUA) asynchronous methods from failing due to null callback arguments. The review feedback highlights critical issues in this implementation, including a data race on the reference counter (ref) that requires atomic operations, and an unbounded memory leak caused by appending callbacks to a global slice that never gets cleared. The reviewer suggests using a thread-safe global singleton instance instead to resolve both the leak and synchronization issues.

Important

The consumer version of Gemini Code Assist on GitHub is being sunset. Starting June 18, 2026, new organization installations will be blocked, and all code review activity will officially cease on July 17, 2026.
For more details on the timeline and next steps, please review the Help Documentation.

[codecov]

Codecov Report

❌ Patch coverage is 75.00000% with 13 lines in your changes missing coverage. Please review.
✅ Project coverage is 45.55%. Comparing base (4e268b4) to head (d132acb).

Files with missing lines	Patch %	Lines
olecallback.go	79.16%	10 Missing ⚠️
iupdateinstaller.go	0.00%	2 Missing ⚠️
iupdatedownloader.go	0.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master      #15      +/-   ##
==========================================
+ Coverage   43.89%   45.55%   +1.66%     
==========================================
  Files          34       35       +1     
  Lines        1392     1440      +48     
==========================================
+ Hits          611      656      +45     
+ Misses        562      561       -1     
- Partials      219      223       +4     

☔ View full report in Codecov by Harness.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.