net: defer synchronous destroy calls in internalConnect

[RajeshKumar11]

Defer socket.destroy() calls in internalConnect and internalConnectMultiple to the next tick. This ensures that error handlers have a chance to be set up before errors are emitted, particularly important when using http.request with a custom lookup function that returns synchronously.

Problem

When using http.request() with a custom synchronous lookup function that returns an IP triggering an immediate error (e.g., via blockList), the error was emitted before the HTTP client had set up its error handler. The HTTP client sets up the error handler via process.nextTick in onSocket(), but the connection error occurred synchronously during net.createConnection().

This caused unhandled 'error' events that could not be caught:

const blockList = new net.BlockList();
blockList.addAddress('127.0.0.1');

const req = http.request({
  host: 'example.com',
  port: 80,
  lookup: (hostname, options, cb) => cb(null, '127.0.0.1', 4),
  family: 4,
  createConnection: (opts) => net.createConnection({ ...opts, blockList })
});

req.on('error', (err) => {
  // This was never called - error was unhandled!
});

Solution

Defer socket.destroy() calls to the next tick in:

• internalConnect() - bind errors, blockList errors, and connect errors
• internalConnectMultiple() - timeout and aggregate errors

This gives callers (especially the HTTP client) time to set up error handlers before errors are emitted.

Testing

Added test/parallel/test-http-request-lookup-error-catchable.js that verifies errors are catchable when using http.request with a synchronous custom lookup and blockList.

Fixes: #48771
Refs: #51038

[nodejs-github-bot]

Review requested:

• @nodejs/net

[codecov]

Codecov Report

❌ Patch coverage is 92.30769% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 89.72%. Comparing base (f77a709) to head (f6abca6).
⚠️ Report is 7 commits behind head on main.

Files with missing lines	Patch %	Lines
lib/net.js	92.30%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #61658      +/-   ##
==========================================
- Coverage   89.74%   89.72%   -0.03%     
==========================================
  Files         674      674              
  Lines      204360   204368       +8     
  Branches    39265    39270       +5     
==========================================
- Hits       183412   183375      -37     
- Misses      13251    13303      +52     
+ Partials     7697     7690       -7     

Files with missing lines	Coverage Δ
lib/net.js	94.52% <92.30%> (+0.01%)	⬆️

... and 29 files with indirect coverage changes

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[pimterry]

This looks good to me, nice fix, thanks @RajeshKumar11! 👍

[nodejs-github-bot]

CI: https://ci.nodejs.org/job/node-test-pull-request/71185/

[jazelly]

nice fix! lgtm