node:zlib: compression options and stream retuning parity cut

[andrewtdiz]

Summary

Use this issue as the PR-cut tracker for Node-compatible zlib option objects and stream retuning. Perry exposes most non-Zstd node:zlib codec shapes, but one-shot codecs, stream factories, Brotli params, dictionaries/output limits, and stream.params() do not yet apply Node's option semantics consistently.

Child Issues

• node:zlib: honor compression options in one-shot and stream codecs #2935 - node:zlib: honor compression options in one-shot and stream codecs
• node:zlib: make stream.params retune compression level and strategy #3285 - node:zlib: make stream.params retune compression level and strategy

Intended PR Boundary

A good medium-sized PR should parse, validate, and apply the common Node zlib options for already implemented codecs:

• one-shot zlib methods: level, strategy, windowBits, memLevel, dictionary, flush / finishFlush, and maxOutputLength where applicable;
• Brotli one-shot and stream methods: params, chunkSize, maxOutputLength, info, and dictionary/decompressor options where applicable;
• stream factories: carry parsed options into encoder/decoder state instead of using fixed defaults;
• stream.params(level, strategy, callback): validate inputs, retune deflate-family streams, and complete the callback with Node-observable semantics.

Exact compressed bytes do not need to match Node when the backend produces a valid stream, but output must be option-sensitive and validation must match Node for covered cases.

Non-Goals

• One-shot callback-form dispatch and callback validation tracked by node:zlib: one-shot codec API parity cut #3103, node:zlib: preserve callback-form gzip and Brotli semantics #3096, and node:zlib: wire callback-form deflate/inflate/unzip codecs #2667.
• Zstd codec internals tracked by node:zlib: implement Zstd codecs beyond export shapes #2510.
• zlib.codes metadata tracked by node:zlib: expose codes error-code table #2688.
• Broad stream Transform rewrites unrelated to applying option state and params().
• Byte-for-byte compression parity for valid streams where backend differences are expected.

Evidence

• docs/runtime-parity-gaps.md lists node:zlib options-adjacent APIs such as stream factories, one-shot raw/Brotli codecs, params(), bytesWritten, bytesRead, crc32, and constants as gaps.
• test-parity/node-suite/zlib already has deterministic round-trip, constants, Brotli, raw, unzip, stream, and crc32 fixtures that can be extended for option-sensitive behavior.
• Source evidence in the child issues points at one-shot codecs using fixed compression defaults, stream factories ignoring _opts, fixed Brotli quality/window settings, and zlib_stream_params() ignoring handle/level/strategy.
• Duplicate searches for node:zlib zlib options level strategy windowBits memLevel dictionary Brotli params quality chunkSize and node:zlib stream.params params level strategy callback retune found this tracker and no active PR.

Acceptance

• Child issues above have focused parity/regression coverage.
• One-shot and stream-factory option objects produce Node-compatible validation and option-sensitive output for covered cases.
• stream.params() retunes supported deflate-family streams or reports Node-compatible errors for covered cases.
• Existing gzip/deflate/raw/Brotli round-trip fixtures keep passing.
• Related parity docs / known-failure entries are updated if touched.

[proggeramlug]

Closing this "parity cut" umbrella tracker as superseded by its granular child issues.

Perry tracks Node/TypeScript parity gaps as granular, per-gap issues (the ones listed under Child Issues above) — that is the workable backlog the maintainer prefers, rather than umbrella roll-ups. Each child issue carries its own Node-vs-Perry evidence, source pointers, and test surface, and remains open and independently tracked; closing this umbrella loses no work, only the duplicate roll-up framing.

The child issues continue to be addressed by focused PRs (each PR auto-closes the specific leaf issues it fixes). If a consolidated tracker is still wanted for this module, feel free to reopen.