feat: fixes mem leak relating to issue-1834

[yowainwright]

Description

• closes [bug] TCP memory leak caused by aborted client connections when streaming data with node-fetch #1834
• closes [feat] improved tests for WHATWG Response and ReadableStream by checking the response body #1882
• closes use pipeline() instead of pipe() #1889

Checklist

• I have ensured my pull request is not behind the main or master branch of the original repository.
• I have rebased all commits where necessary so that reviewing this pull request can be done without having to merge it first.
• I have written a commit message that passes commitlint linting.
• I have ensured that my code changes pass linting tests.
• I have ensured that my code changes pass unit tests.
• I have described my pull request and the reasons for code changes along with context if necessary.

Checklist for 1834 (before re-pinging team)

• Update stackblitz - stackblitz demostrating error and fix
• Address comments
• Re-review after merging 2 issues together

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 99.90%. Comparing base (ffd497a) to head (954a474).
⚠️ Report is 1 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #1893   +/-   ##
=======================================
  Coverage   99.90%   99.90%           
=======================================
  Files           9        9           
  Lines        2060     2074   +14     
=======================================
+ Hits         2058     2072   +14     
  Misses          2        2           

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[yowainwright]

@fengmk2 could you review this as you have time? 🙏 🙇
happy to help elsewhere! 👍
Thanks for all of your efforts!

[fengmk2]

Is it the same issue fixed by #1889?

[yowainwright]

@fengmk2 thanks for your thoughtfulness and time!
Will review #1889 and your comments and update accordingly. 🙇

[yowainwright]

@fengmk2 updated.

• Prefer logic of use pipeline() instead of pipe() #1889 but added error handling for backwards compatibility.
• Adds tests for readableStream

[fengmk2]

@jonathanong Do you want to take another look?

[fengmk2]

I will merge this fix as a better stream handler and release it as a minor version.

It's a feature better than a bug :)🤣

[fengmk2]

@yowainwright Thank you for your excellent contribution!

[Copilot]

Pull Request Overview

This PR addresses memory leaks related to stream handling in Koa by replacing the .pipe() method with Stream.pipeline() and improving stream cleanup. The changes ensure proper stream destruction and error handling to prevent resource leaks when streams are replaced or responses are aborted.

Key changes:

• Replaced .pipe() with Stream.pipeline() for automatic stream cleanup and error handling
• Added explicit cleanup of original streams when the response body is set to null
• Removed manual error listeners on streams since pipeline handles errors automatically

Reviewed Changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 2 comments.

File	Description
lib/response.js	Adds cleanup logic to destroy original streams when body is nullified, removes manual error listener attachment
lib/application.js	Refactors stream handling to use Stream.pipeline() instead of .pipe() for proper cleanup and error propagation
tests/response/body.test.js	Updates test expectations to reflect removal of manual error listeners on streams
tests/application/respond.test.js	Adds comprehensive test coverage for ReadableStream, Response objects, and pipeline error handling scenarios

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[fengmk2]

@yowainwright If no one gets feedback this week, I'll release this change on Sunday.

[fengmk2]

@yowainwright I consecutively set 2 streams that will cause exceptions, deleting here is problematic.

ctx.body = fs.createReadStream('does not exist');
ctx.body = fs.createReadStream('does not exist');

will throw unhandled error: Error: ENOENT: no such file or directory, open 'does not exist'

[yowainwright]

😳 Looking! Do you have anymore initial insights? Will dig into this shortly.
Update here @fengmk2 .

• fix: adds steam clean up #1910

[yowainwright]

@fengmk2 update below. 🙇

• fix: adds steam clean up #1910

[fengmk2]

v3.1.0 released https://github.com/koajs/koa/releases/tag/v3.1.0