Wiki - https://fedoraproject.org/wiki/Changes/CrystalLanguage
his is a proposed Change for Fedora Linux.
This document represents a proposed Change. As part of the Changes
process, proposals are publicly announced in order to receive
community feedback. This proposal will only be implemented if approved
by the Fedora Engineering Steering Committee.
== Summary ==
This proposal introduces official native support for the
[[crystal|Crystal programming language]] compiler
({{package|crystal}}), its dependency manager ({{package|shards}}), an
automated spec generator ({{package|cr2rpm}}), and standard RPM
packaging macros ({{package|crystal-rpm-macros}}) into Fedora Linux.
Shard libraries will be packaged following the '''Shard-as-RPM'''
model, enabling offline, secure, and reproducible compilation across
the distribution.
== Owner ==
* Name: [[User:Renich|Rénich Bon Ćirić]]
* Email: renich@woralelandia.com
== Detailed Description ==
Crystal ([https://crystal-lang.org]) is a statically typed compiled
language designed for developer productivity and systems-level
execution performance.
The Fedora implementation uses the '''Shard-as-RPM''' model:
* Each shard library is packaged as an independent RPM package
installing source trees to
<code>%{_datadir}/crystal/shards/<name>-<version></code> (with
compatibility links for default releases).
* Parallel coexistence of multiple shard versions is supported without
filesystem collisions, enabling applications to build against specific
SemVer versions.
* Network access during package builds is prohibited; dependencies are
provided locally by installed RPMs.
* The compiler discovers installed shard libraries offline via
<code>CRYSTAL_PATH="lib:%{crystal_shards_dir}:%{_datadir}/crystal/src"</code>.
* Spec generation, license mapping (SPDX), and topological mock build
ordering are automated via {{package|cr2rpm}}.
* Compiler bootstrapping complies with Fedora's
[[Packaging:Guidelines#No_pre-compiled_binaries|No Pre-compiled
Binaries Policy]] via a standard transient Koji side-tag bootstrap.
== Feedback ==
Community feedback and architectural planning have been discussed on
Fedora Discussion at
[https://discussion.fedoraproject.org/t/bringing-crystal-to-fedora-linux/182632
Bringing Crystal to Fedora Linux].
== Benefit to Fedora ==
* '''Air-Gapped & High-Security Deployments''': Enables building and
deploying Crystal software in isolated or air-gapped environments
without external internet access or dynamic Git downloads.
* '''Supply Chain Integrity''': Protects against upstream Git
repository tampering, branch deletion, and dependency confusion by
anchoring all dependencies to cryptographic RPM package checksums.
* '''Centralized Security Auditing & Patching''': System
administrators and security scanners (OpenSCAP, DNF, RPM) can track,
audit, and patch Crystal libraries system-wide without inspecting
ad-hoc vendor directories.
* '''Hermetic & Reproducible Builds''': Conforms strictly with Fedora
release engineering standards, ensuring deterministic builds in Koji
and Mock.
* '''Modern Systems Language''': Provides a high-performance compiled
language with native LLVM optimization, green threads concurrency, and
seamless C ABI interoperability.
== Scope ==
* Proposal owners:
** Package and maintain {{package|crystal}}, {{package|shards}},
{{package|crystal-rpm-macros}}, and {{package|cr2rpm}}.
** Execute the initial bootstrap build in Koji using a staging side-tag.
** Publish official Crystal packaging guidelines.
** Maintain core ecosystem packages ({{package|ameba}},
{{package|flaw}}, {{package|kemal}}).
* Other developers: No direct impact on existing packages. Developers
can begin packaging Crystal applications and shard libraries.
* Release engineering: Coordinate initial bootstrap build and provide
a staging side-tag if required
([https://forge.fedoraproject.org/releng/tickets/issues/13511 RelEng
Ticket #13511]).
* Policies and guidelines: Fedora Packaging Guidelines updated with
dedicated Crystal section
([https://discussion.fedoraproject.org/t/draft-guidelines-crystal-packaging-guidelines-changes-crystallanguage/200733
FPC Draft Discussion #200733]).
* Trademark approval: N/A (not needed for this Change)
* Alignment with the Fedora Strategy: Expands Fedora's ecosystem of
modern, memory-efficient compiled systems languages.
== Upgrade/compatibility impact ==
No impact on existing packages or system upgrades. This change
introduces new packages and does not modify existing system defaults
or libraries.
== How To Test ==
=== Hardware / Environment Requirements ===
Standard x86_64 or aarch64 Fedora Linux system (or Mock chroot).
=== System Preparation ===
sudo dnf install crystal shards cr2rpm crystal-rpm-macros
=== Verification Steps ===
Generate a spec file from a shard repository:
cr2rpm generate --path ./my-shard
Analyze dependency tree and build order:
cr2rpm deps --path ./my-shard --format mock
Build and verify an application binary:
crystal build --release -o hello src/hello.cr
./hello
Run package tests in an isolated mock chroot:
mock -r fedora-rawhide-x86_64 rebuild my-package.src.rpm
== User Experience ==
Fedora users and developers can install the Crystal compiler and
shards package manager directly via standard package management:
sudo dnf install crystal shards
Crystal binaries compile with full Fedora hardening flags (PIE, Full
RELRO, Stack Protection) and integrate with GDB and LLDB out of the
box.
== Dependencies ==
* Compiler runtime: {{package|llvm-devel}}, {{package|gc-devel}},
{{package|pcre2-devel}}, {{package|libffi-devel}}.
* Standard library: {{package|openssl-devel}}, {{package|zlib-devel}},
{{package|gmp-devel}}, {{package|libyaml-devel}},
{{package|libxml2-devel}}.
* Opt-in/legacy event loop: {{package|libevent-devel}}.
== Contingency Plan ==
* Contingency mechanism: Retarget for Fedora N+1. Crystal packages
remain available via Copr and staging repos.
* Contingency deadline: Beta freeze.
* Blocks release? No.
== Documentation ==
* Implementation Plan:
[https://codeberg.org/renich/crystal-in-fedora/src/branch/master/plan.rst
plan.rst]
* Packaging Guidelines:
[https://codeberg.org/renich/crystal-in-fedora/src/branch/master/guidelines/packaging-crystal.rst
packaging-crystal.rst]
* Crystal Official Site: [https://crystal-lang.org/ crystal-lang.org]
* Upstream Language Repository:
[https://github.com/crystal-lang/crystal
github.com/crystal-lang/crystal]
* Fedora Tooling & Planning Repository:
[https://codeberg.org/renich/crystal-in-fedora
codeberg.org/renich/crystal-in-fedora]
== Release Notes ==
Fedora now includes official support for the Crystal programming
language, including the compiler ({{package|crystal}}), dependency
manager ({{package|shards}}), and full RPM packaging macros
({{package|crystal-rpm-macros}}). Developers can build native,
high-performance Crystal applications and package shards offline using
standard Fedora tooling.
Proposal owners:
Package and
--
Aoife Moloney
Fedora Operations Architect
Fedora Project
Matrix: @amoloney:fedora.im
IRC: amoloney
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