fix(zlib): prevent zip from degrading default compression

[proggeramlug]

Summary

• Configure zip to keep its existing codec set without forcing flate2's zlib-rs backend across the combined Perry build.
• Keep node:zlib on flate2's intended Rust backend, restoring the default gzip ratio from about 31 KiB to about 16 KiB for the issue's 4 MiB payload.
• Add a product-level regression fixture covering gzipSync, callback gzip, and promisify(gzip).

Closes #10810.

Cause

The zip crate's default deflate feature enables deflate-flate2-zlib-rs. Cargo feature unification applied that backend to perry-ext-zlib in a combined build. At default level 6, the issue payload compressed to 31,388 bytes with that backend and 16,592 bytes with flate2's normal Rust backend.

Verification

• Built perry, perry-runtime-static, perry-stdlib-static, and perry-ext-zlib in one Cargo invocation.
• Compiled and ran test_gap_10810_zlib_default_compression.ts with the rebuilt Perry binary: all three compression checks printed true.
• Ran the fixture with Node 26: all three checks printed true.
• cargo test --profile perry-dev -p perry update_checker -- --nocapture (22 passed, including ZIP extraction and corrupt/archive traversal rejection)
• Verified the perry feature graph contains flate2 rust_backend/miniz_oxide and no zlib-rs.
• cargo fmt --all -- --check
• bash scripts/check_file_size.sh
• git diff --check

Summary by CodeRabbit

• Bug Fixes
  • Improved default gzip and deflate compression so outputs retain expected compression efficiency when using the CLI.
  • Preserved ZIP archive codec support while preventing compression backend conflicts.
  • Added regression coverage for synchronous, callback-based, and promisified gzip operations.

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📥 Commits

Reviewing files that changed from the base of the PR and between 57a6d60 and f00c854.

📒 Files selected for processing (3)

• changelog.d/11020-zlib-default-compression.md
• crates/perry/Cargo.toml
• test-files/test_gap_10810_zlib_default_compression.ts

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📝 Walkthrough

Walkthrough

The ZIP dependency now uses a backend-neutral flate2 feature configuration. A regression test checks gzip output from synchronous, callback, and promisified APIs. The changelog documents the fix.

Changes

zlib compression backend

Layer / File(s)	Summary
Select the flate2 backend crates/perry/Cargo.toml	The ZIP dependency disables default features and enables an explicit codec set with deflate-flate2.
Validate gzip output test-files/test_gap_10810_zlib_default_compression.ts, changelog.d/11020-zlib-default-compression.md	The test checks that three gzip call forms produce output below 3,000 bytes. The changelog records the compression fix and regression coverage.

Priority: ➖ Normal

Estimated code review effort: 2 (Simple) | ~10 minutes

Change: Bug fix · Severity of issue fixed: Medium

Merge Risk: ⚪ Minimal · up to f00c8

The change restores compact gzip behavior and adds effective regression coverage; no actionable merge-blocking risk remains.

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 1 functions across 1 files. (2 skipped: 2 …	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title is concise, specific, and accurately describes the main change: preventing the zip dependency from degrading default zlib compression.
Description check	✅ Passed	The description is mostly complete. It explains the change, cause, linked issue, verification steps, affected APIs, and test results. It uses a "Verification" section instead of the template's "Test p…
Linked Issues check	✅ Passed	The changes satisfy #10810. crates/perry/Cargo.toml removes the feature-unifying zip.workspace dependency and selects deflate-flate2 with the existing codec set. This keeps node:zlib on the in…
Out of Scope Changes check	✅ Passed	The changed files stay within #10810. The Cargo dependency change fixes backend selection, the fixture provides regression coverage for all affected call forms, and the changelog documents the fix. No…

Full details: Docstring Coverage

Explanation

Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 1 functions across 1 files. (2 skipped: 2 unsupported.)

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[proggeramlug]

Landed on main in merge train 260 (#11085), released as v0.5.1643 at d8f24f15ed.

Cherry-picked from this PR's head f00c8545fc and validated as one tree — CI 22/22 green, all 6 gap-suite shards. A train rebase gives the commits new SHAs, so GitHub cannot auto-close the source PR; closing by hand.

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