http: fix keep-alive socket reuse race in requestOnFinish

[martinslota]

When the response ends before the request's 'finish' event fires, responseOnEnd() and requestOnFinish() can both call responseKeepAlive(), corrupting the socket that the agent may have already handed to another request.

This PR adds a !req.destroyed guard to requestOnFinish() so the second call is skipped when the socket has already been released.

Fixes #60001.

Relates to aws/aws-sdk-js-v3#6426.

[nodejs-github-bot]

Review requested:

• @nodejs/http
• @nodejs/net

[martinslota]

The fix can also be backported to Node.js versions 19 and upwards.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 89.73%. Comparing base (911b158) to head (52c3851).
⚠️ Report is 4 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #61710      +/-   ##
==========================================
- Coverage   89.74%   89.73%   -0.01%     
==========================================
  Files         675      675              
  Lines      204601   204605       +4     
  Branches    39319    39317       -2     
==========================================
- Hits       183611   183610       -1     
+ Misses      13275    13270       -5     
- Partials     7715     7725      +10     

Files with missing lines	Coverage Δ
lib/_http_client.js	97.37% <100.00%> (+<0.01%)	⬆️

... and 26 files with indirect coverage changes

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[pimterry]

LGTM 👍 Nice work on a tricky edge case @martinslota

[nodejs-github-bot]

CI: https://ci.nodejs.org/job/node-test-pull-request/71269/

[martinslota]

Looks like some checks have failed - some of them related to an event loop delay test (example):

duration_ms: 7221.425
exitcode: 1
severity: fail
stack: |-
  node:internal/assert/utils:146
    throw error;
    ^

  AssertionError [ERR_ASSERTION]: The expression evaluated to a falsy value:

    assert(histogram.min > 0)

      at Immediate.<anonymous> (/home/iojs/build/workspace/node-test-commit-linux-containered/test/sequential/test-performance-eventloopdelay.js:74:9)
      at Immediate._onImmediate (/home/iojs/build/workspace/node-test-commit-linux-containered/test/common/index.js:507:15)
      at process.processImmediate (node:internal/timers:504:21) {
    generatedMessage: true,
    code: 'ERR_ASSERTION',
    actual: false,
    expected: true,
    operator: '==',
    diff: 'simple'
  }

  Node.js v26.0.0-pre

I'm not really sure how to fix that.