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Crystal 0.30.1 released!

Brian J. Cardiff

Crystal 0.30.1 has been released!

This release comes with some regression fixes and support for recent version of dependencies that were causing some headaches. No new features were added.

There are 12 commits since 0.30.0 by 6 contributors.

Let’s review some highlights in this release. But don’t miss the rest of the release changelog.



For Crystal 0.30.0 we tried to upgrade to LLVM 6.0.1 for our official darwin packages. Those packages use a custom build of LLVM. On those builds we include assertions via LLVM_ENABLE_ASSERTIONS=ON, as a way to double-check we are using LLVM properly.

In this case, instead of finding a wrong use of LLVM, we found a bug/unhandled case in LLVM. After we reported it a fix was proposed but either way we needed to take some actions before that fix landed.

A repackaging of 0.30.0-2 for darwin was done using LLVM 3.9.1. A workaround to avoid the LLVM bug was done in #8063.

The 0.30.1 darwin package is using LLVM 6.0.1.

There are other outstanding issues regarding debug metadata in release mode that have been unsolved for a long time, but since almost nobody runs LLVM with assertions, those are unnoticed. Assertions are good sometimes (take 1).

Abstract method check

The abstract method check introduced in 0.30.0 got some improvements to consider the methods defined across the whole hierarchy of types. Read more at #8035.

Standard library


libevent 2.1.11 was released shortly after Crystal 0.30.0. There is a new constraint enforced by it that got in conflict with how fibers were resumed by our runtime. Read more at #8058. Bonus point: it seems that we have a slight performance improvement with that change. Assertions are good sometimes (take 2).


One of the recent optimizations caused headers to arrive with an unexpected case for some use-cases. This was fixed in #8061.

Meanwhile, a socket leaking after failed SSL connect was fixed in #8025.

Next steps

Please update your Crystal and report any issues. We will keep moving forward regarding 0.31.

Once again, check your code with --warnings=all. This will help in the migration of your codebase and will probably push some feedback about that tool.

Stay tuned!