http: fix just-merged change that could silently truncate responses

[pimterry]

This fixes an issue introduced 2 days ago in #64278. With that change, errors that emit after HTTP response headers are received but before the response is completed are swallowed silently.

This PR preserves the core change there, but covers the "response set but not yet completed" window properly so errors here still fire as expected.

[nodejs-github-bot]

Review requested:

• @nodejs/http
• @nodejs/net

[github-actions]

Fast-track has been requested by @pimterry. Please 👍 to approve.

[bjohansebas]

LGTM!

[mcollina]

lgtm

[mcollina]

I'm also ok to revert #64278.

[nodejs-github-bot]

CI: https://ci.nodejs.org/job/node-test-pull-request/74823/

[pimterry]

I'm also ok to revert

I think we can roll forwards instead. The issue is real, and the fix is roughly correct, it just misses a couple of cases en route. AFAICT with some small changes this'll work as intended.

That said, I say "cases" plural because I've found another one: if the response is completed but the request is still going, this will now swallow errors we previously emitted on the still open request.

That can happen because request/response lifetimes are surprisingly independent, servers can finish responding while the request is still going. Most plausible example: the server could send an HTTP 202 to confirm an upload based on headers alone, before the body is fully delivered, expecting the request to keep writing it out even though the response side is closed. It's definitely weird, but it's valid HTTP AFAICT and I wouldn't be surprised at all if somebody does it and expects to get errors if it goes wrong.

Bonus fix for that incoming now.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 90.23%. Comparing base (3ac95f2) to head (30901e2).
⚠️ Report is 3 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #64507      +/-   ##
==========================================
- Coverage   90.23%   90.23%   -0.01%     
==========================================
  Files         741      739       -2     
  Lines      241692   241668      -24     
  Branches    45541    45547       +6     
==========================================
- Hits       218097   218073      -24     
- Misses      15113    15152      +39     
+ Partials     8482     8443      -39     

Files with missing lines	Coverage Δ
lib/_http_client.js	97.63% <100.00%> (-0.01%)	⬇️

... and 37 files with indirect coverage changes

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