[stdlib, 6.2] Make String.makeContiguousUTF8() strictly true #82896
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glessard
added
32 bit only
🍒 release cherry pick
|
@swift-ci please test |
DougGregor
approved these changes
Jul 9, 2025
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Explanation:
Until now, StringProtocol.makeContiguousUTF8() only considered whether or not a String or Substring heap allocation contained contiguous UTF8, disregarding whether a stack-allocated instance was discontiguous. This is no longer tenable when these types vend UTF8Span and Span properties, so we now also consider whether the small string form contains contiguous code units. If the small form contains discontiguously-stored code units, then it is replaced by a new heap-allocated String in contiguous storage. This new code path is specific to ABI-stable, 32-bit platforms.
Resolves: rdar://154331399
Risk: Low. This change is only in
@_alwaysEmitIntoClientcode.Main branch PR: [stdlib] Make String.makeContiguousUTF8() strictly true #82851
Review by: @kperryua
Testing: new test, existing tests