fix: SslHandler retrieval for HTTP/1.1 client certificate auth

[jasstionzyf]

Summary

Fixes #22504 — SslHandler retrieval in ReactorNetty4BaseHttpChannel.get() prioritizes the parent channel over the current channel, breaking client certificate authentication on HTTP/1.1.

Root cause

For HTTP/1.1 connections, the connection channel has a parent server channel, but its SslHandler is on the current channel. The original code checked parent() first, which returned null — so the Security plugin could not retrieve the SSLEngine or peer certificate.

HTTP/2 stream channels correctly inherit the TLS handler from the parent, so HTTP/2 was not affected.

Fix

Check the current channel first, and fall back to the parent only when no SslHandler is found:

channels[0] = channel.pipeline().get(NettyPipeline.SslHandler);
if (channels[0] == null && channel.parent() != null) {
    channels[0] = channel.parent().pipeline().get(NettyPipeline.SslHandler);
}

Verified matrix (by reporter)

Protocol	Auth	Result
HTTP/1.1	valid cert	200 ✓
HTTP/2	valid cert	200 ✓
HTTP/1.1	no auth	401 ✓
HTTP/2	no auth	401 ✓
HTTP/1.1	basic auth	200 ✓
HTTP/2	basic auth	200 ✓

Issues resolved

Closes #22504

Signed-off-by: jasstionzyf jasstionzyf@gmail.com

[github-actions]

PR Reviewer Guide 🔍

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🧪 No relevant tests

🔒 No security concerns identified

✅ No TODO sections

🔀 No multiple PR themes

⚡ No major issues detected

[github-actions]

✅ Gradle check result for 4155b2b: SUCCESS

[codecov]

Codecov Report

❌ Patch coverage is 0% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 73.55%. Comparing base (c93e9af) to head (4155b2b).
⚠️ Report is 2 commits behind head on main.

Files with missing lines	Patch %	Lines
...p/reactor/netty4/ReactorNetty4BaseHttpChannel.java	0.00%	2 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##               main   #22509      +/-   ##
============================================
+ Coverage     73.43%   73.55%   +0.11%     
- Complexity    76472    76538      +66     
============================================
  Files          6104     6104              
  Lines        346573   346587      +14     
  Branches      49886    49888       +2     
============================================
+ Hits         254514   254916     +402     
+ Misses        71798    71441     -357     
+ Partials      20261    20230      -31     

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[reta]

This is duplicate of #22506