[Foundation] 1-ary IndexPath forms invalid range on slices #10317
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@swift-ci please test |
itaiferber
approved these changes
Jun 16, 2017
Catfish-Man
approved these changes
Jun 16, 2017
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This is a cherry pick of pr #10311
1-ary IndexPaths incorrectly implemented slicing for ranges of 1..<1
This resolves swiftlang/swift-corelibs-foundation#3851.
Explanation:
IndexPath had a missing case for 1..<1 in 1-ary variant storage when slicing ranges. This commit adds that missing case (since integers are not naturally exhaustive and fall into a default case they were hitting the "out of range" cases)
Scope:
This is only runtime behavior for IndexPath and is a un-common use case (but still something that we should definitely not let fail)
Radar (and possibly SR Issue):
Risk:
This is relatively low risk since it is only a runtime behavior and only changes an un-common case.
Testing:
A unit test was added testing both the reported case of
dropFirst()as well as the root cause of slicing.