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Oh I like the solution of using the drop guard for the access! I have just one comment, this looks very nice :)
The scripts match "[PATCH .*]" which breaks if a single patch is involved, which is "[PATCH]". Signed-off-by: Gary Guo <gary@garyguo.net>
When a field has been initialized, `init!`/`pin_init!` create a reference
or pinned reference to the field so it can be accessed later during the
initialization of other fields. However, the reference it created is
incorrectly `&'static` rather than just the scope of the initializer.
This means that you can do
init!(Foo {
a: 1,
_: {
let b: &'static u32 = a;
}
})
which is unsound.
This is caused by `&mut (*#slot).#ident`, which actually allows arbitrary
lifetime, so this is effectively `'static`. Somewhat ironically, the safety
justification of creating the accessor is.. "SAFETY: TODO".
Fix it by adding `Deref`/`DerefMut` implementation to `DropGuard` and
derive the reference from dereferencing `DropGuard` instead. The lifetime
of `DropGuard` is exactly what we want for these accessors.
The old accessor creation code also has a purpose of preventing unaligned
fields. So a `let _ = &(*#slot).#ident` still needs to be present, but this
no longer has to care about pinning, so it is moved to just before the
guard generation.
Fixes: db96c51 ("add references to previously initialized fields")
Signed-off-by: Gary Guo <gary@garyguo.net>
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When a field has been initialized,
init!/pin_init!create a reference or pinned reference to the field so it can be accessed later during the initialization of other fields. However, the reference it created is incorrectly&'staticrather than just the scope of the initializer.This means that you can do
which is unsound.
This is caused by
&mut (*#slot).#ident, which actually allows arbitrary lifetime, so this is effectively'static. Somewhat ironically, the safety justification of creating the accessor is.. "SAFETY: TODO".Fix it by adding
Deref/DerefMutimplementation toDropGuardand derive the reference from dereferencingDropGuardinstead. The lifetime ofDropGuardis exactly what we want for these accessors.The old accessor creation code also has a purpose of preventing unaligned fields. So a
let _ = &(*#slot).#identis kept in place to avoid that unsoundness.