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libc: make structs non_exhaustive by default. #4579

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libc: make structs non_exhaustive by default. #4579

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38 changes: 36 additions & 2 deletions src/macros.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -101,20 +101,38 @@ macro_rules! prelude {
/// Implement `Clone` and `Copy` for a struct, as well as `Debug`, `Eq`, `Hash`, and
/// `PartialEq` if the `extra_traits` feature is enabled.
///
/// By default, it will mark a struct as `non_exhaustive`. To opt out, use the attribute
/// `#[@not_non_exhaustive]` as the first attribute of the struct.
///
/// Use [`s_no_extra_traits`] for structs where the `extra_traits` feature does not
/// make sense, and for unions.
macro_rules! s {
($(
$(#[@$not_non_exhaustive:ident])*
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This should just be able to match a literal, right?

Suggested change
$(#[@$not_non_exhaustive:ident])*
$(#[not_non_exhaustive])?

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Nope, it fails with "attempted to repeat an expression containing no syntax variables"

$(#[$attr:meta])*
pub $t:ident $i:ident { $($field:tt)* }
)*) => ($(
s!(it: $(#[$attr])* pub $t $i { $($field)* });
s!(it: $(#[@$not_non_exhaustive])* $(#[$attr])* pub $t $i { $($field)* });
)*);

(it: $(#[$attr:meta])* pub union $i:ident { $($field:tt)* }) => (
compile_error!("unions cannot derive extra traits, use s_no_extra_traits instead");
);

(it: #[@not_non_exhaustive] $(#[$attr:meta])* pub struct $i:ident { $($field:tt)* }) => (
__item! {
#[repr(C)]
#[cfg_attr(
feature = "extra_traits",
::core::prelude::v1::derive(Debug, Eq, Hash, PartialEq)
)]
#[::core::prelude::v1::derive(::core::clone::Clone, ::core::marker::Copy)]
#[allow(deprecated)]
$(#[$attr])*
pub struct $i { $($field)* }
}
);

(it: $(#[$attr:meta])* pub struct $i:ident { $($field:tt)* }) => (
__item! {
#[repr(C)]
Expand All @@ -124,6 +142,7 @@ macro_rules! s {
)]
#[::core::prelude::v1::derive(::core::clone::Clone, ::core::marker::Copy)]
#[allow(deprecated)]
#[non_exhaustive]
$(#[$attr])*
pub struct $i { $($field)* }
}
Expand All @@ -133,6 +152,9 @@ macro_rules! s {
/// Implement `Clone` and `Copy` for a tuple struct, as well as `Debug`, `Eq`, `Hash`,
/// and `PartialEq` if the `extra_traits` feature is enabled.
///
/// By default, it will mark a struct as `non_exhaustive`. To opt out, use the attribute
/// `#[@not_non_exhaustive]` as the first attribute of the struct.
///
/// This is the same as [`s`] but works for tuple structs.
macro_rules! s_paren {
($(
Expand All @@ -157,10 +179,11 @@ macro_rules! s_paren {
/// Most items will prefer to use [`s`].
macro_rules! s_no_extra_traits {
($(
$(#[@$not_non_exhaustive:ident])*
$(#[$attr:meta])*
pub $t:ident $i:ident { $($field:tt)* }
)*) => ($(
s_no_extra_traits!(it: $(#[$attr])* pub $t $i { $($field)* });
s_no_extra_traits!(it: $(#[@$not_non_exhaustive])* $(#[$attr])* pub $t $i { $($field)* });
)*);

(it: $(#[$attr:meta])* pub union $i:ident { $($field:tt)* }) => (
Expand All @@ -179,11 +202,22 @@ macro_rules! s_no_extra_traits {
}
);

(it: #[@not_non_exhaustive] $(#[$attr:meta])* pub struct $i:ident { $($field:tt)* }) => (
__item! {
#[repr(C)]
#[::core::prelude::v1::derive(::core::clone::Clone, ::core::marker::Copy)]
#[cfg_attr(feature = "extra_traits", ::core::prelude::v1::derive(Debug))]
$(#[$attr])*
pub struct $i { $($field)* }
}
);

(it: $(#[$attr:meta])* pub struct $i:ident { $($field:tt)* }) => (
__item! {
#[repr(C)]
#[::core::prelude::v1::derive(::core::clone::Clone, ::core::marker::Copy)]
#[cfg_attr(feature = "extra_traits", ::core::prelude::v1::derive(Debug))]
#[non_exhaustive]
$(#[$attr])*
pub struct $i { $($field)* }
}
Expand Down
2 changes: 0 additions & 2 deletions src/unix/linux_like/linux/mod.rs
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Expand Up @@ -798,7 +798,6 @@ s! {
}

// linux/openat2.h
#[non_exhaustive]
pub struct open_how {
pub flags: crate::__u64,
pub mode: crate::__u64,
Expand Down Expand Up @@ -1329,7 +1328,6 @@ s! {

// linux/pidfd.h

#[non_exhaustive]
pub struct pidfd_info {
pub mask: crate::__u64,
pub cgroupid: crate::__u64,
Expand Down
1 change: 1 addition & 0 deletions src/unix/mod.rs
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Expand Up @@ -149,6 +149,7 @@ s! {
pub h_addr_list: *mut *mut c_char,
}

#[@not_non_exhaustive]
pub struct iovec {
pub iov_base: *mut c_void,
pub iov_len: size_t,
Expand Down
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