strengthen doc warning about CString::from_raw #36018
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r? @aturon (rust_highfive has picked a reviewer for you, use r? to override) |
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r? @steveklabnik or @GuillaumeGomez |
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@bors: r+ rollup |
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📌 Commit 70aa463 has been approved by |
strengthen doc warning about CString::from_raw Saw unsound code using this function on IRC.
| /// of the string will be recalculated from the pointer. | ||
| /// obtained by calling `into_raw` on a `CString`. In particular, using this method | ||
| /// to create a `CString` pointing at memory that will be freed by other code | ||
| /// (such as a C library) will lead to undefined behavior! |
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Creating CString from arbitrary allocation is not UB. Doing anything other than mem::forget(create) and CString::from_raw(create) what is.
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I feel like we’ve brainstormed a nice way to say this somewhere already. The way String and Vec state this invariant is pretty good.
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You're right. That's why I didn't say "is UB". I said "will lead to UB" which is indeed likely if you use from_raw on anything that didn't come from into_raw.
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Well, sure, it doesn’t always lead to UB regardless of its arguments either (i.e. if you immediately forget it, however unreasonable such code would be). Moreover using similar format as String::from_raw and Vec::from_raw helps consistency :)
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@bors: r- sure, let's talk about it 😄 |
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PS: also this fails tidy. |
Hmmm... want to squash those commits? ;) |
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@jonathandturner sure I will squash if this goes in as is. Sounds like it needs some more work. I can copy the style from Vec::from_raw_parts as @nagisa suggested. |
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Yes, let's copy that style and get this PR merged, finally. |
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Done. |
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@bors r=steveklabnik rollup |
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📌 Commit 0d3d23b has been approved by |
strengthen doc warning about CString::from_raw Saw unsound code using this function on IRC.
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💔 Test failed - auto-mac-32-opt |
strengthen doc warning about CString::from_raw Saw unsound code using this function on IRC.
Saw unsound code using this function on IRC.