[5.3] [Function builders] Use buildLimitedAvailability() for #available block #32995
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
The use of "if #available" in function builders can subvert availability checking if the function builder carries all type information for the values within the "then" block outside of the "else" block. Tighten up the model in two ways: * Check whether the type coming out of an "if #available" references any declarations that are not available in the outer context, to close up the model. * If the function builder provides a buildLimitedAvailability(_:) operation, call that on the result of the "then" block in an "if that it cannot leak out of the "if #available"; if it doesn't, the check above will still fire. Stage this in with a warning so function builders out there in the wild can adapt. We'll upgrade the warning to an error later. Fixes rdar://problem/65021017.
|
@swift-ci please test |
|
Build failed |
|
@swift-ci please test macOS |
devincoughlin
approved these changes
Jul 21, 2020
AnthonyLatsis
added
swift 5.3
🍒 release cherry pick
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
The use of "if #available" in function builders can subvert availability
checking if the function builder carries all type information for the
values within the "then" block outside of the "else" block. Tighten up
the model in two ways:
any declarations that are not available in the outer context, to close
up the model.
operation, call that on the result of the "then" block in an "if
that it cannot leak out of the "if #available"; if it doesn't, the
check above will still fire.
Stage this in with a warning so function builders out there in the wild
can adapt. We'll upgrade the warning to an error later.
Fixes rdar://problem/65021017.
Original: #32994