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std: make Debug representations of [Lazy, Once]*[Cell, Lock] consistent with Mutex and RwLock

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`Mutex` prints `<locked>` as a field value when its inner value cannot be accessed, but the lazy types print a fixed string like "`OnceCell(Uninit)`". This could cause confusion if the inner type is a unit type named `Uninit` and does not respect the pretty-printing flag. With this change, the format message is now "`OnceCell(<uninit>)`", consistent with `Mutex`.
This commit is contained in:
joboet
2023-03-18 20:06:12 +01:00
parent 9e7f72c57d
commit b7e68dfc94
6 changed files with 22 additions and 38 deletions
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8
library/std/src/sync/lazy_lock.rs
View File

@@ -157,10 +157,12 @@ impl<T: Default> Default for LazyLock<T> {
#[unstable(feature = "lazy_cell", issue = "109736")]
impl<T: fmt::Debug, F> fmt::Debug for LazyLock<T, F> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
let mut d = f.debug_tuple("LazyLock");
match self.get() {
Some(v) => f.debug_tuple("LazyLock").field(v).finish(),
None => f.write_str("LazyLock(Uninit)"),
}
Some(v) => d.field(v),
None => d.field(&format_args!("<uninit>")),
};
d.finish()
}
}

8
library/std/src/sync/mutex.rs
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@@ -490,13 +490,7 @@ impl<T: ?Sized + fmt::Debug> fmt::Debug for Mutex<T> {
d.field("data", &&**err.get_ref());
}
Err(TryLockError::WouldBlock) => {
struct LockedPlaceholder;
impl fmt::Debug for LockedPlaceholder {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.write_str("<locked>")
}
}
d.field("data", &LockedPlaceholder);
d.field("data", &format_args!("<locked>"));
}
}
d.field("poisoned", &self.poison.get());

8
library/std/src/sync/once_lock.rs
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@@ -366,10 +366,12 @@ impl<T> const Default for OnceLock<T> {
#[stable(feature = "once_cell", since = "CURRENT_RUSTC_VERSION")]
impl<T: fmt::Debug> fmt::Debug for OnceLock<T> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
let mut d = f.debug_tuple("OnceLock");
match self.get() {
Some(v) => f.debug_tuple("Once").field(v).finish(),
None => f.write_str("Once(Uninit)"),
}
Some(v) => d.field(v),
None => d.field(&format_args!("<uninit>")),
};
d.finish()
}
}

8
library/std/src/sync/rwlock.rs
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@@ -485,13 +485,7 @@ impl<T: ?Sized + fmt::Debug> fmt::Debug for RwLock<T> {
d.field("data", &&**err.get_ref());
}
Err(TryLockError::WouldBlock) => {
struct LockedPlaceholder;
impl fmt::Debug for LockedPlaceholder {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.write_str("<locked>")
}
}
d.field("data", &LockedPlaceholder);
d.field("data", &format_args!("<locked>"));
}
}
d.field("poisoned", &self.poison.get());