Branch: refs/heads/main
Home: https://github.com/WebKit/WebKit
Commit: 460abf576622806c66767e3ac5c9f01ee912070e
https://github.com/WebKit/WebKit/commit/460abf576622806c66767e3ac5c9f01ee912070e
Author: Geoffrey Garen <gga...@apple.com>
Date: 2024-11-03 (Sun, 03 Nov 2024)
Changed paths:
M Source/WTF/wtf/IndexedRange.h
Log Message:
-----------
IndexedRange is unsafe to use with temporaries
https://bugs.webkit.org/show_bug.cgi?id=282503
rdar://139127354
Reviewed by Mike Wyrzykowski and Chris Dumez.
This was technically undef:
for (auto [ index, value ] : IndexedRange(std::span(collection))) { ... }
because IndexedRange kept a reference to its constructor argument, which was
a destroyed temporary.
The solution has three parts:
1. Use an IndexedRange(Collection&&) overload to detect construction with a
temporary.
2. Store begin() / end() iterators instead of a reference to the collection.
This eliminates the reference to a destroyed temporary -- but adds use of
an iterator after invalidation. Yayboo.
3. static_assert that the temporary supports std::ranges::borrowed_range,
which makes use of an iterator after invalidation well-defined. Yay.
* Source/WTF/wtf/IndexedRange.h:
(WTF::IndexedRange::IndexedRange):
(WTF::IndexedRange::begin):
(WTF::IndexedRange::end):
Canonical link: https://commits.webkit.org/286060@main
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