RFC 0030: Forward Compatibility Policy - #30
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straight-shoota
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This pull request has been mentioned on Crystal Forum. There might be relevant details there: https://forum.crystal-lang.org/t/rfc-0030-forward-compatibility-policy-30/9112/1 |
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It seems too long the time frame of 8 releases (2 years) of forward compatibility. In my point-of-view, reducing it is mostly positive for the language. Learning from what Go and Rust do, a time frame of 1 year looks more balanced. |
| > [!NOTE] Backwards Compatibility | ||
| > This policy does not affect the [_Backwards Compatibility_ policy]: | ||
| > Any compiler of the 1.x release series can still compile a program written for 1.0. | ||
| > That includes being able to build a 1.0 compiler from any future compiler of the 1.x series. |
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Does this imply that we must not drop LLVM 11 support for the rest of Crystal 1.x, since Crystal 1.0 only supported up to LLVM 11.1?
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I believe so, yes. We guarantee that existing APIs continue working in future minor releases. The LLVM bindings are part of stdlib, so they need to maintain compatibility. And if stdlib does, the compiler can, too.
However, we do not explicitly specify whether or how stability guarantees apply to third party library bindings, especially when those libraries are no longer maintained.
Anyway, that's unrelated to the forward compatibility policy.
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Though unrelated to forward compatibility, that's a very good point about backward compatibility. If the compiler can't assume LLVM 18 despite being available in the bootstrap version, that would be a problem.
Hm, the code for Crystal 1.0 supports LLVM 11 for the code it will generate, and it will use the LLVM bindings from the 1.0 release, so whatever if the current compiler uses LLVM 22 and the current compiler doesn't support LLVM 11 anymore: the newly compiled Crystal 1.0 should still compile & work?
beta-ziliani
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beta-ziliani
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This is great, thanks @straight-shoota for putting it forth!
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@paulocoghi Maybe you're right and a shorter support window would be even better. But I believe two years are already pretty good. Let's start with that and figure out how things go from there. |
Restrict forward compatibility CI to cover only the eight most recent releases. Implements crystal-lang/rfcs#30
This follows from crystal-lang/rfcs#30
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MERGED: https://github.com/crystal-lang/rfcs/blob/master/text/0030-forward-compatibility.md