Bug 2445516 - Review Request: zlib - Compression and decompression library
Summary: Review Request: zlib - Compression and decompression library
Keywords:
Status: NEW
Alias: None
Product: Fedora
Classification: Fedora
Component: Package Review
Version: rawhide
Hardware: Unspecified
OS: Linux
unspecified
medium
Target Milestone: ---
Assignee: Nobody's working on this, feel free to take it
QA Contact: Fedora Extras Quality Assurance
URL: https://www.zlib.net/
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-03-07 18:52 UTC by Benson Muite
Modified: 2026-03-11 16:42 UTC (History)
5 users (show)

Fixed In Version:
Clone Of:
Environment:
Last Closed:
Type: ---
Embargoed:


Attachments (Terms of Use)

Description Benson Muite 2026-03-07 18:52:00 UTC
spec: https://fed500.fedorapeople.org/zlib.spec
srpm: https://fed500.fedorapeople.org/zlib-1.3.2-1.fc43.src.rpm

description:
Zlib is a general-purpose, patent-free, lossless data compression
library which is used by many different programs

fas: fed500

Rationale for bringing this back to Fedora:
The package was replaced by zlib-ng which provides a compat package.
However, zlib-ng uses compression algorithms that are not fully
deterministic, as such cannot be used in pipelines that require
reproducible builds and use checksums on compressed artifacts.  One
way to have both zlib-ng and zlib is to use modules, though other
suggestions are welcome.

Previous discussion:
https://fedoraproject.org/wiki/Changes/ZlibNGTransition

Reproducible: Always

Comment 1 Fedora Review Service 2026-03-08 05:47:54 UTC
Copr build:
https://copr.fedorainfracloud.org/coprs/build/10200642
(succeeded)

Review template:
https://download.copr.fedorainfracloud.org/results/@fedora-review/fedora-review-2445516-zlib/fedora-rawhide-x86_64/10200642-zlib/fedora-review/review.txt

Found issues:

- No gcc, gcc-c++ or clang found in BuildRequires
  Read more: https://docs.fedoraproject.org/en-US/packaging-guidelines/C_and_C++/
- A package with this name already exists. Please check https://src.fedoraproject.org/rpms/zlib, https://src.fedoraproject.org/tests/zlib
  Read more: https://docs.fedoraproject.org/en-US/packaging-guidelines/Naming/#_conflicting_package_names

Please know that there can be false-positives.

---
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Comment 2 Neal Gompa 2026-03-08 14:57:41 UTC
(In reply to Benson Muite from comment #0)
> 
> The package was replaced by zlib-ng which provides a compat package.
> However, zlib-ng uses compression algorithms that are not fully
> deterministic, as such cannot be used in pipelines that require
> reproducible builds and use checksums on compressed artifacts.  One
> way to have both zlib-ng and zlib is to use modules, though other
> suggestions are welcome.
> 
> Previous discussion:
> https://fedoraproject.org/wiki/Changes/ZlibNGTransition
> 
> Reproducible: Always

Have you reached out to the Fedora Reproducible Builds folks about this? This is the first time I'm hearing of this.

Comment 3 Terje Rosten 2026-03-08 19:17:05 UTC
Very few artifacts shipped in Fedora is gzipped I think so it's not a problem for distribution as such,
however having a deterministic zip command available in distro is important for several use cases.

Comment 4 Terje Rosten 2026-03-08 19:25:39 UTC
Is this the same issue or something else?

https://github.com/zlib-ng/zlib-ng/pull/2102 - Make deflate output deterministic if PREFIX3(stream) is reused after deflateReset

Comment 5 Zbigniew Jędrzejewski-Szmek 2026-03-09 12:52:38 UTC
Non-deterministic compression would be very bad. I hope it's just the above bug which is already resolved.

Comment 6 Benson Muite 2026-03-11 16:42:33 UTC
Sorry, believe they are deterministic but not stable from release to release:
https://github.com/zlib-ng/zlib-ng/issues/2216


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