Add a type argument to the ABI accessor function signature.
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grynspan
added
bug
grynspan
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SeanROlszewski,
briancroom,
stmontgomery and
suzannaratcliff
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We access the test content record section directly instead of using some (non-existent) type-safe Swift API. On some platforms (Darwin in particular), it is possible for two copies of the testing library to be loaded at runtime, and for them to have incompatible definitions of types like `Test`. That means one library's `@Test` macro could produce a test content record that is then read by the other library's discovery logic, resulting in a stack smash or worse. We can resolve this issue by adding a `type` argument to the accessor function we define for test content records; the body of the accessor can then compare the value of this argument against the expected Swift type of its result and, if they don't match, bail early. The new argument is defined as a pointer _to_ a Swift type rather than as a Swift type directly because `@convention(c)` functions cannot directly reference Swift types. The value of the new argument can be safely ignored if the type of the test content record's value is and always has been `@frozen`.
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grynspan
commented
Feb 4, 2025
grynspan
commented
Feb 4, 2025
| value at `type` does not match the test content record's expected type, the | ||
| accessor function must return `false` and must not modify `outValue`. | ||
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| <!-- TODO: discuss this argument's value in Embedded Swift (no metatypes) --> |
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In Embedded Swift, we can just say "the value of this argument is unspecified."
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@swift-ci test |
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@swift-ci test |
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@swift-ci test Windows |
stmontgomery
approved these changes
Feb 4, 2025
The implementation actually does use a different type for If/when we make the |
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We access the test content record section directly instead of using some (non-existent) type-safe Swift API. On some platforms (Darwin in particular), it is possible for two copies of the testing library to be loaded at runtime, and for them to have incompatible definitions of types like
Test. That means one library's@Testmacro could produce a test content record that is then read by the other library's discovery logic, resulting in a stack smash or worse.We can resolve this issue by adding a
typeargument to the accessor function we define for test content records; the body of the accessor can then compare the value of this argument against the expected Swift type of its result and, if they don't match, bail early.The new argument is defined as a pointer to a Swift type rather than as a Swift type directly because
@convention(c)functions cannot directly reference Swift types. The value of the new argument can be safely ignored if the type of the test content record's value is and always has been@frozen.Checklist: