Homebrew
How to enforce a minimum version of clang on macOS? #5977
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Description of issueOn macOS, the latest version of the "Xcode command line tools" installs Apple clang 16.0.0. How would you enforce that minimum version of clang in a formula? The problem is the support of C++20. Up to version 15, clang support for C++20 is buggy. So, when an application is developed in C++20 (or whose code has been upgraded to C++20), building it requires clang 16.0.0 or higher. The problem just emerged with the auto-bump of the new version of the TSDuck project. See the auto-bump PR here. It seems that the tests started with a build on macOS 13 with some old version of clang. The build failed (because of the bugs in the old clang) and the whole process stopped. Between the last version and the new one, the code of the project has been upgraded to C++20 (allowing a lot of code simplifications). In the CI of the project, on macOS, the setup phase tests the version of clang and enforces an upgrade of the "Xcode command line tools" if clang version is lower than 16. How would you transpose that requirement in a formula? |
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Replies: 1 comment 2 replies
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The You can also conditionally add a dependency based on the version of the compiler available, like done here. |
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Excellent, thanks @alebcay, it looks like what I need. Just one question, before I update the formula. What does happen when the requirement is not met on a given platform, for instance an old macOS? Does it force the installation of the right compiler? Does it mark the product as unavailable on that old version of macOS while keeping it available on more recent ones? Does the PR fail? This is not clear from the documentation. |
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Homebrew core PRs are only ever built and tested against the supported platforms (currently, latest 3 macOS versions and Intel 64-bit Linux). If it can't be built on a supported platform, you'll need to add an OS version dependency, e.g. If it requires a specific compiler version that's not normally installed, you'll have to add a |
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The
fails_withDSL method should be able to do what you're asking for here. You can see this in action in thebtopformula. See also this doc section about compiler selection.You can also conditionally add a dependency based on the version of the compiler available, like done here.