#[non_exhaustive]pub enum NotFoundCode {
NotFound,
Unknown(UnknownVariantValue),
}
Expand description
When writing a match expression against NotFoundCode
, it is important to ensure
your code is forward-compatible. That is, if a match arm handles a case for a
feature that is supported by the service but has not been represented as an enum
variant in a current version of SDK, your code should continue to work when you
upgrade SDK to a future version in which the enum does include a variant for that
feature.
Here is an example of how you can make a match expression forward-compatible:
# let notfoundcode = unimplemented!();
match notfoundcode {
NotFoundCode::NotFound => { /* ... */ },
other @ _ if other.as_str() == "NewFeature" => { /* handles a case for `NewFeature` */ },
_ => { /* ... */ },
}
The above code demonstrates that when notfoundcode
represents
NewFeature
, the execution path will lead to the second last match arm,
even though the enum does not contain a variant NotFoundCode::NewFeature
in the current version of SDK. The reason is that the variable other
,
created by the @
operator, is bound to
NotFoundCode::Unknown(UnknownVariantValue("NewFeature".to_owned()))
and calling as_str
on it yields "NewFeature"
.
This match expression is forward-compatible when executed with a newer
version of SDK where the variant NotFoundCode::NewFeature
is defined.
Specifically, when notfoundcode
represents NewFeature
,
the execution path will hit the second last match arm as before by virtue of
calling as_str
on NotFoundCode::NewFeature
also yielding "NewFeature"
.
Explicitly matching on the Unknown
variant should
be avoided for two reasons:
- The inner data
UnknownVariantValue
is opaque, and no further information can be extracted. - It might inadvertently shadow other intended match arms.
Variants (Non-exhaustive)§
This enum is marked as non-exhaustive
NotFound
Unknown(UnknownVariantValue)
Unknown
contains new variants that have been added since this code was generated.
Implementations§
Trait Implementations§
Source§impl AsRef<str> for NotFoundCode
impl AsRef<str> for NotFoundCode
Source§impl Clone for NotFoundCode
impl Clone for NotFoundCode
Source§fn clone(&self) -> NotFoundCode
fn clone(&self) -> NotFoundCode
1.0.0 · Source§fn clone_from(&mut self, source: &Self)
fn clone_from(&mut self, source: &Self)
source
. Read moreSource§impl Debug for NotFoundCode
impl Debug for NotFoundCode
Source§impl From<&str> for NotFoundCode
impl From<&str> for NotFoundCode
Source§impl FromStr for NotFoundCode
impl FromStr for NotFoundCode
Source§impl Hash for NotFoundCode
impl Hash for NotFoundCode
Source§impl Ord for NotFoundCode
impl Ord for NotFoundCode
Source§fn cmp(&self, other: &NotFoundCode) -> Ordering
fn cmp(&self, other: &NotFoundCode) -> Ordering
1.21.0 · Source§fn max(self, other: Self) -> Selfwhere
Self: Sized,
fn max(self, other: Self) -> Selfwhere
Self: Sized,
Source§impl PartialEq for NotFoundCode
impl PartialEq for NotFoundCode
Source§impl PartialOrd for NotFoundCode
impl PartialOrd for NotFoundCode
impl Eq for NotFoundCode
impl StructuralPartialEq for NotFoundCode
Auto Trait Implementations§
impl Freeze for NotFoundCode
impl RefUnwindSafe for NotFoundCode
impl Send for NotFoundCode
impl Sync for NotFoundCode
impl Unpin for NotFoundCode
impl UnwindSafe for NotFoundCode
Blanket Implementations§
Source§impl<T> BorrowMut<T> for Twhere
T: ?Sized,
impl<T> BorrowMut<T> for Twhere
T: ?Sized,
Source§fn borrow_mut(&mut self) -> &mut T
fn borrow_mut(&mut self) -> &mut T
Source§impl<T> CloneToUninit for Twhere
T: Clone,
impl<T> CloneToUninit for Twhere
T: Clone,
Source§impl<Q, K> Comparable<K> for Q
impl<Q, K> Comparable<K> for Q
Source§impl<Q, K> Equivalent<K> for Q
impl<Q, K> Equivalent<K> for Q
Source§impl<Q, K> Equivalent<K> for Q
impl<Q, K> Equivalent<K> for Q
Source§fn equivalent(&self, key: &K) -> bool
fn equivalent(&self, key: &K) -> bool
key
and return true
if they are equal.Source§impl<T> Instrument for T
impl<T> Instrument for T
Source§fn instrument(self, span: Span) -> Instrumented<Self>
fn instrument(self, span: Span) -> Instrumented<Self>
Source§fn in_current_span(self) -> Instrumented<Self>
fn in_current_span(self) -> Instrumented<Self>
Source§impl<T> IntoEither for T
impl<T> IntoEither for T
Source§fn into_either(self, into_left: bool) -> Either<Self, Self>
fn into_either(self, into_left: bool) -> Either<Self, Self>
self
into a Left
variant of Either<Self, Self>
if into_left
is true
.
Converts self
into a Right
variant of Either<Self, Self>
otherwise. Read moreSource§fn into_either_with<F>(self, into_left: F) -> Either<Self, Self>
fn into_either_with<F>(self, into_left: F) -> Either<Self, Self>
self
into a Left
variant of Either<Self, Self>
if into_left(&self)
returns true
.
Converts self
into a Right
variant of Either<Self, Self>
otherwise. Read more