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RalfJung opened this issue May 19, 2025 · 3 comments · Fixed by #141405
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We rely on an undocumented property of GetUserProfileDirectoryW #141254

RalfJung opened this issue May 19, 2025 · 3 comments · Fixed by #141405
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C-bug Category: This is a bug. O-windows Operating system: Windows T-libs Relevant to the library team, which will review and decide on the PR/issue.

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@RalfJung
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The docs say that the size is written on failure, but in practice it is also written on success and we rely on that. See #141244 and rust-lang/miri#4332.

We shouldn't use system APIs outside their documented contract, so we should either adjust our implementation or get Microsoft to update the docs to promise this behavior we have been relying on.

Cc @ChrisDenton
@rustbot rustbot added the needs-triage This issue may need triage. Remove it if it has been sufficiently triaged. label May 19, 2025
@RalfJung RalfJung added O-windows Operating system: Windows T-libs Relevant to the library team, which will review and decide on the PR/issue. labels May 19, 2025
This was referenced May 19, 2025
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@jieyouxu jieyouxu added C-bug Category: This is a bug. and removed needs-triage This issue may need triage. Remove it if it has been sufficiently triaged. labels May 20, 2025
@workingjubilee
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see MicrosoftDocs/sdk-api#1810

@ChrisDenton
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Wait, I recognise that name.

I'd completely forgot about writing that.

@RalfJung RalfJung mentioned this issue May 22, 2025
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@cgettys-microsoft
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see MicrosoftDocs/sdk-api#1810
This has been merged. I think this issue can be closed based on that being merged - Ralf's PR seems a reasonable enough way to close it though.

matthiaskrgr added a commit to matthiaskrgr/rust that referenced this issue May 23, 2025
@matthiaskrgr
Rollup merge of rust-lang#141405 - RalfJung:GetUserProfileDirectoryW,…
f35311c 
… r=ChrisDenton

GetUserProfileDirectoryW is now documented to always store the size

Update to match MicrosoftDocs/sdk-api#1810

Also fix a bug in the Miri implementation while I am starting at that code...

r? `@ChrisDenton`
Fixes rust-lang#141254
matthiaskrgr added a commit to matthiaskrgr/rust that referenced this issue May 24, 2025
@matthiaskrgr
Rollup merge of rust-lang#141405 - RalfJung:GetUserProfileDirectoryW,…
08f7f1f 
… r=ChrisDenton

GetUserProfileDirectoryW is now documented to always store the size

Update to match MicrosoftDocs/sdk-api#1810

Also fix a bug in the Miri implementation while I am starting at that code...

r? ``@ChrisDenton``
Fixes rust-lang#141254
@bors bors closed this as completed in 48c4a46 May 24, 2025
rust-timer added a commit that referenced this issue May 24, 2025
@rust-timer
Unrolled build for #141405
bb49804 
Rollup merge of #141405 - RalfJung:GetUserProfileDirectoryW, r=ChrisDenton

GetUserProfileDirectoryW is now documented to always store the size

Update to match MicrosoftDocs/sdk-api#1810

Also fix a bug in the Miri implementation while I am starting at that code...

r? ```@ChrisDenton```
Fixes #141254
github-actions bot pushed a commit to model-checking/verify-rust-std that referenced this issue May 26, 2025
@matthiaskrgr
Rollup merge of rust-lang#141405 - RalfJung:GetUserProfileDirectoryW,…
074bf43 
… r=ChrisDenton

GetUserProfileDirectoryW is now documented to always store the size

Update to match MicrosoftDocs/sdk-api#1810

Also fix a bug in the Miri implementation while I am starting at that code...

r? ```@ChrisDenton```
Fixes rust-lang#141254
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GetUserProfileDirectoryW is now documented to always store the size RalfJung/rust
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@RalfJung @ChrisDenton @jieyouxu @workingjubilee @rustbot @cgettys-microsoft