gh-141968: Use bytearray.take_bytes() in more I/O paths

[methane]

• Issue: Remove bytearray to bytes copies in stdlib using take_bytes #141968

[chatgpt-codex-connector]

Codex Review Summary

This comment shows the latest Codex review activity on this pull request.

Review	Status	Commit	Review trigger
📝 Code Review	✅ Completed 2026-09-05T15:23:41.568035Z	94ff007	PR opened

ℹ️ About Codex in GitHub

Your team has set up Codex to review pull requests in this repo. Reviews are triggered when you

• Open a pull request for review
• Mark a draft as ready
• Comment "@codex review" or "@codex security review".

Codex reacts with 👀 while any review is running, comments if it has suggestions, and reacts with 👍 once all reviews finish with no findings.

[Copilot]

🟢 Approval recommended

Both changes preserve return types and behavior while safely eliminating unnecessary copies from locally owned bytearrays.

Pull request overview

Uses bytearray.take_bytes() to avoid final buffer copies in I/O and ZIP decryption paths.

Changes:

• Optimizes _IOBase.readline().
• Optimizes legacy ZIP decryption output.

File summaries

File	Description
Modules/_io/iobase.c	Transfers the readline buffer directly into bytes.
Lib/zipfile/__init__.py	Transfers decrypted output directly into bytes.

Review details

• Files reviewed: 2/2 changed files
• Comments generated: 0
• Review effort level: Balanced

---

💡 Add a code-review agent skill or configure MCP servers for context-aware, tailored reviews. Learn more in the docs.

[cmaloney]

👍

I had a PR for the zipfile one previously (#142240). I think it is reasonable to do but hard to benchmark (the decrypter usage is uncommon).

For .readline() it probably makes sense to move entirely to PyBytesWriter (https://peps.python.org/pep-0782/). That is a separate larger scope change though.

[methane]

OK. I used PyBytesWriter in #157024