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Invert all build.rs cfgs
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This allows non-Cargo builds to generally not get involved in cfgs. As
long as one is using a reasonably recent toolchain, no cfgs need to be
set and you'll get a fully-featured build.
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@dtolnay
dtolnay committed Jan 2, 2022
1 parent 7af97c6 commit 55a7ced
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Showing 8 changed files with 105 additions and 100 deletions.
89 changes: 45 additions & 44 deletions serde/build.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -17,37 +17,38 @@ fn main() {
// std::collections::Bound was stabilized in Rust 1.17
// but it was moved to core::ops later in Rust 1.26:
// https://doc.rust-lang.org/core/ops/enum.Bound.html
if minor >= 26 {
println!("cargo:rustc-cfg=ops_bound");
} else if minor >= 17 && cfg!(feature = "std") {
println!("cargo:rustc-cfg=collections_bound");
if minor < 26 {
println!("cargo:rustc-cfg=no_ops_bound");
if minor < 17 {
println!("cargo:rustc-cfg=no_collections_bound");
}
}

// core::cmp::Reverse stabilized in Rust 1.19:
// https://doc.rust-lang.org/stable/core/cmp/struct.Reverse.html
if minor >= 19 {
println!("cargo:rustc-cfg=core_reverse");
if minor < 19 {
println!("cargo:rustc-cfg=no_core_reverse");
}

// CString::into_boxed_c_str and PathBuf::into_boxed_path stabilized in Rust 1.20:
// https://doc.rust-lang.org/std/ffi/struct.CString.html#method.into_boxed_c_str
// https://doc.rust-lang.org/std/path/struct.PathBuf.html#method.into_boxed_path
if minor >= 20 {
println!("cargo:rustc-cfg=de_boxed_c_str");
println!("cargo:rustc-cfg=de_boxed_path");
if minor < 20 {
println!("cargo:rustc-cfg=no_de_boxed_c_str");
println!("cargo:rustc-cfg=no_de_boxed_path");
}

// From<Box<T>> for Rc<T> / Arc<T> stabilized in Rust 1.21:
// https://doc.rust-lang.org/std/rc/struct.Rc.html#impl-From<Box<T>>
// https://doc.rust-lang.org/std/sync/struct.Arc.html#impl-From<Box<T>>
if minor >= 21 {
println!("cargo:rustc-cfg=de_rc_dst");
if minor < 21 {
println!("cargo:rustc-cfg=no_de_rc_dst");
}

// Duration available in core since Rust 1.25:
// https://blog.rust-lang.org/2018/03/29/Rust-1.25.html#library-stabilizations
if minor >= 25 {
println!("cargo:rustc-cfg=core_duration");
if minor < 25 {
println!("cargo:rustc-cfg=no_core_duration");
}

// 128-bit integers stabilized in Rust 1.26:
Expand All @@ -56,56 +57,56 @@ fn main() {
// Disabled on Emscripten targets before Rust 1.40 since
// Emscripten did not support 128-bit integers until Rust 1.40
// (https://github.com/rust-lang/rust/pull/65251)
if minor >= 26 && (!emscripten || minor >= 40) {
println!("cargo:rustc-cfg=integer128");
if minor < 26 || emscripten && minor < 40 {
println!("cargo:rustc-cfg=no_integer128");
}

// Inclusive ranges methods stabilized in Rust 1.27:
// https://github.com/rust-lang/rust/pull/50758
// Also Iterator::try_for_each:
// https://blog.rust-lang.org/2018/06/21/Rust-1.27.html#library-stabilizations
if minor >= 27 {
println!("cargo:rustc-cfg=range_inclusive");
println!("cargo:rustc-cfg=iterator_try_fold");
if minor < 27 {
println!("cargo:rustc-cfg=no_range_inclusive");
println!("cargo:rustc-cfg=no_iterator_try_fold");
}

// Non-zero integers stabilized in Rust 1.28:
// https://blog.rust-lang.org/2018/08/02/Rust-1.28.html#library-stabilizations
if minor >= 28 {
println!("cargo:rustc-cfg=num_nonzero");
if minor < 28 {
println!("cargo:rustc-cfg=no_num_nonzero");
}

// Current minimum supported version of serde_derive crate is Rust 1.31.
if minor >= 31 {
println!("cargo:rustc-cfg=serde_derive");
if minor < 31 {
println!("cargo:rustc-cfg=no_serde_derive");
}

// TryFrom, Atomic types, non-zero signed integers, and SystemTime::checked_add
// stabilized in Rust 1.34:
// https://blog.rust-lang.org/2019/04/11/Rust-1.34.0.html#tryfrom-and-tryinto
// https://blog.rust-lang.org/2019/04/11/Rust-1.34.0.html#library-stabilizations
if minor >= 34 {
println!("cargo:rustc-cfg=core_try_from");
println!("cargo:rustc-cfg=num_nonzero_signed");
println!("cargo:rustc-cfg=systemtime_checked_add");

// Whitelist of archs that support std::sync::atomic module. Ideally we
// would use #[cfg(target_has_atomic = "...")] but it is not stable yet.
// Instead this is based on rustc's compiler/rustc_target/src/spec/*.rs.
let has_atomic64 = target.starts_with("x86_64")
|| target.starts_with("i686")
|| target.starts_with("aarch64")
|| target.starts_with("powerpc64")
|| target.starts_with("sparc64")
|| target.starts_with("mips64el")
|| target.starts_with("riscv64");
let has_atomic32 = has_atomic64 || emscripten;
if has_atomic64 {
println!("cargo:rustc-cfg=std_atomic64");
}
if has_atomic32 {
println!("cargo:rustc-cfg=std_atomic");
}
if minor < 34 {
println!("cargo:rustc-cfg=no_core_try_from");
println!("cargo:rustc-cfg=no_num_nonzero_signed");
println!("cargo:rustc-cfg=no_systemtime_checked_add");
}

// Whitelist of archs that support std::sync::atomic module. Ideally we
// would use #[cfg(target_has_atomic = "...")] but it is not stable yet.
// Instead this is based on rustc's compiler/rustc_target/src/spec/*.rs.
let has_atomic64 = target.starts_with("x86_64")
|| target.starts_with("i686")
|| target.starts_with("aarch64")
|| target.starts_with("powerpc64")
|| target.starts_with("sparc64")
|| target.starts_with("mips64el")
|| target.starts_with("riscv64");
let has_atomic32 = has_atomic64 || emscripten;
if minor < 34 || !has_atomic64 {
println!("cargo:rustc-cfg=no_std_atomic64");
}
if minor < 34 || !has_atomic32 {
println!("cargo:rustc-cfg=no_std_atomic");
}
}

Expand Down
60 changes: 32 additions & 28 deletions serde/src/de/impls.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -4,7 +4,7 @@ use de::{
Deserialize, Deserializer, EnumAccess, Error, SeqAccess, Unexpected, VariantAccess, Visitor,
};

#[cfg(any(core_duration, feature = "std", feature = "alloc"))]
#[cfg(any(feature = "std", feature = "alloc", not(no_core_duration)))]
use de::MapAccess;

use seed::InPlaceSeed;
Expand Down Expand Up @@ -637,10 +637,10 @@ macro_rules! forwarded_impl {
}
}

#[cfg(all(feature = "std", de_boxed_c_str))]
#[cfg(all(feature = "std", not(no_de_boxed_c_str)))]
forwarded_impl!((), Box<CStr>, CString::into_boxed_c_str);

#[cfg(core_reverse)]
#[cfg(not(no_core_reverse))]
forwarded_impl!((T), Reverse<T>, Reverse);

////////////////////////////////////////////////////////////////////////////////
Expand Down Expand Up @@ -1604,7 +1604,7 @@ impl<'de> Deserialize<'de> for PathBuf {
}
}

#[cfg(all(feature = "std", de_boxed_path))]
#[cfg(all(feature = "std", not(no_de_boxed_path)))]
forwarded_impl!((), Box<Path>, PathBuf::into_boxed_path);

////////////////////////////////////////////////////////////////////////////////
Expand Down Expand Up @@ -1685,11 +1685,7 @@ forwarded_impl!((T), Box<[T]>, Vec::into_boxed_slice);
#[cfg(any(feature = "std", feature = "alloc"))]
forwarded_impl!((), Box<str>, String::into_boxed_str);

#[cfg(all(
not(de_rc_dst),
feature = "rc",
any(feature = "std", feature = "alloc")
))]
#[cfg(all(no_de_rc_dst, feature = "rc", any(feature = "std", feature = "alloc")))]
forwarded_impl! {
/// This impl requires the [`"rc"`] Cargo feature of Serde.
///
Expand All @@ -1701,11 +1697,7 @@ forwarded_impl! {
(T), Arc<T>, Arc::new
}

#[cfg(all(
not(de_rc_dst),
feature = "rc",
any(feature = "std", feature = "alloc")
))]
#[cfg(all(no_de_rc_dst, feature = "rc", any(feature = "std", feature = "alloc")))]
forwarded_impl! {
/// This impl requires the [`"rc"`] Cargo feature of Serde.
///
Expand Down Expand Up @@ -1772,7 +1764,11 @@ where

////////////////////////////////////////////////////////////////////////////////

#[cfg(all(de_rc_dst, feature = "rc", any(feature = "std", feature = "alloc")))]
#[cfg(all(
not(no_de_rc_dst),
feature = "rc",
any(feature = "std", feature = "alloc")
))]
macro_rules! box_forwarded_impl {
(
$(#[doc = $doc:tt])*
Expand All @@ -1793,7 +1789,11 @@ macro_rules! box_forwarded_impl {
};
}

#[cfg(all(de_rc_dst, feature = "rc", any(feature = "std", feature = "alloc")))]
#[cfg(all(
not(no_de_rc_dst),
feature = "rc",
any(feature = "std", feature = "alloc")
))]
box_forwarded_impl! {
/// This impl requires the [`"rc"`] Cargo feature of Serde.
///
Expand All @@ -1805,7 +1805,11 @@ box_forwarded_impl! {
Rc
}

#[cfg(all(de_rc_dst, feature = "rc", any(feature = "std", feature = "alloc")))]
#[cfg(all(
not(no_de_rc_dst),
feature = "rc",
any(feature = "std", feature = "alloc")
))]
box_forwarded_impl! {
/// This impl requires the [`"rc"`] Cargo feature of Serde.
///
Expand Down Expand Up @@ -1849,7 +1853,7 @@ forwarded_impl!((T), RwLock<T>, RwLock::new);
// secs: u64,
// nanos: u32,
// }
#[cfg(any(core_duration, feature = "std"))]
#[cfg(any(feature = "std", not(no_core_duration)))]
impl<'de> Deserialize<'de> for Duration {
fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
where
Expand Down Expand Up @@ -2127,11 +2131,11 @@ impl<'de> Deserialize<'de> for SystemTime {

const FIELDS: &'static [&'static str] = &["secs_since_epoch", "nanos_since_epoch"];
let duration = try!(deserializer.deserialize_struct("SystemTime", FIELDS, DurationVisitor));
#[cfg(systemtime_checked_add)]
#[cfg(not(no_systemtime_checked_add))]
let ret = UNIX_EPOCH
.checked_add(duration)
.ok_or_else(|| D::Error::custom("overflow deserializing SystemTime"));
#[cfg(not(systemtime_checked_add))]
#[cfg(no_systemtime_checked_add)]
let ret = Ok(UNIX_EPOCH + duration);
ret
}
Expand Down Expand Up @@ -2167,7 +2171,7 @@ where
}
}

#[cfg(range_inclusive)]
#[cfg(not(no_range_inclusive))]
impl<'de, Idx> Deserialize<'de> for RangeInclusive<Idx>
where
Idx: Deserialize<'de>,
Expand Down Expand Up @@ -2319,7 +2323,7 @@ mod range {

////////////////////////////////////////////////////////////////////////////////

#[cfg(any(ops_bound, collections_bound))]
#[cfg(any(not(no_ops_bound), all(feature = "std", not(no_collections_bound))))]
impl<'de, T> Deserialize<'de> for Bound<T>
where
T: Deserialize<'de>,
Expand Down Expand Up @@ -2430,7 +2434,7 @@ where
macro_rules! nonzero_integers {
( $( $T: ident, )+ ) => {
$(
#[cfg(num_nonzero)]
#[cfg(not(no_num_nonzero))]
impl<'de> Deserialize<'de> for num::$T {
fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
where
Expand All @@ -2455,7 +2459,7 @@ nonzero_integers! {
NonZeroUsize,
}

#[cfg(num_nonzero_signed)]
#[cfg(not(no_num_nonzero_signed))]
nonzero_integers! {
NonZeroI8,
NonZeroI16,
Expand All @@ -2471,7 +2475,7 @@ serde_if_integer128! {
NonZeroU128,
}

#[cfg(num_nonzero_signed)]
#[cfg(not(no_num_nonzero_signed))]
nonzero_integers! {
NonZeroI128,
}
Expand Down Expand Up @@ -2599,7 +2603,7 @@ where
}
}

#[cfg(all(feature = "std", std_atomic))]
#[cfg(all(feature = "std", not(no_std_atomic)))]
macro_rules! atomic_impl {
($($ty:ident)*) => {
$(
Expand All @@ -2615,14 +2619,14 @@ macro_rules! atomic_impl {
};
}

#[cfg(all(feature = "std", std_atomic))]
#[cfg(all(feature = "std", not(no_std_atomic)))]
atomic_impl! {
AtomicBool
AtomicI8 AtomicI16 AtomicI32 AtomicIsize
AtomicU8 AtomicU16 AtomicU32 AtomicUsize
}

#[cfg(all(feature = "std", std_atomic64))]
#[cfg(all(feature = "std", not(no_std_atomic64)))]
atomic_impl! {
AtomicI64 AtomicU64
}
Expand Down
2 changes: 1 addition & 1 deletion serde/src/de/mod.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1215,7 +1215,7 @@ pub trait Deserializer<'de>: Sized {
}

// Not public API.
#[cfg(all(serde_derive, any(feature = "std", feature = "alloc")))]
#[cfg(all(not(no_serde_derive), any(feature = "std", feature = "alloc")))]
#[doc(hidden)]
fn __deserialize_content<V>(
self,
Expand Down
4 changes: 2 additions & 2 deletions serde/src/integer128.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -66,15 +66,15 @@
/// ($($tt:tt)*) => {};
/// }
/// ```
#[cfg(integer128)]
#[cfg(not(no_integer128))]
#[macro_export]
macro_rules! serde_if_integer128 {
($($tt:tt)*) => {
$($tt)*
};
}

#[cfg(not(integer128))]
#[cfg(no_integer128)]
#[macro_export]
#[doc(hidden)]
macro_rules! serde_if_integer128 {
Expand Down
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