Add capture-checking annotations to scala.util.boundary
#22775
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Shouldn't cc changes in the library go to https://github.com/scala/scala3/tree/main/scala2-library-cc/src/scala and not the actual library ? |
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@sjrd what's your opinion on the breaking changes? |
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Breaking change or not, I don't think we have consensus about taking the risk of introducing CC annotations in the standard standard library.
So far, it has always been pretty clear that CC goes to an alternate library that people can depend on if they want to. Here this is a much bigger "attack surface".
At the very least this requires a Core discussion.
Right, I overlooked that. Nevertheless, I agree with @sjrd, we don't have a consensus about adding cc-related code in the stdlib. |
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This was merged as part of #23688. |
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Adds capture-tracking annotations to
scala.util.boundary.The following changes are made:
Label[T]is now a capability, directly inheritingcaps.Capability.Breakexception:.labelfield. This is a source-breaking change. - however,labelis stillprivate[boundary], which should make it TASTy- and binary-compatible.Breakexception, if some code is manually implementingboundary.apply's logic, we instead provide aisSameLabelAsmethod, that compares the givenLabel[T]with the innerLabelwithout leaking it.Breakexceptions may still possibly cause them to escape theboundary.To demonstrate that capture-checking works, a test is included.