#[non_exhaustive]pub enum VolumeModificationState {
Completed,
Failed,
Modifying,
Optimizing,
Unknown(UnknownVariantValue),
}Expand description
When writing a match expression against VolumeModificationState, 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 volumemodificationstate = unimplemented!();
match volumemodificationstate {
VolumeModificationState::Completed => { /* ... */ },
VolumeModificationState::Failed => { /* ... */ },
VolumeModificationState::Modifying => { /* ... */ },
VolumeModificationState::Optimizing => { /* ... */ },
other @ _ if other.as_str() == "NewFeature" => { /* handles a case for `NewFeature` */ },
_ => { /* ... */ },
}
The above code demonstrates that when volumemodificationstate represents
NewFeature, the execution path will lead to the second last match arm,
even though the enum does not contain a variant VolumeModificationState::NewFeature
in the current version of SDK. The reason is that the variable other,
created by the @ operator, is bound to
VolumeModificationState::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 VolumeModificationState::NewFeature is defined.
Specifically, when volumemodificationstate represents NewFeature,
the execution path will hit the second last match arm as before by virtue of
calling as_str on VolumeModificationState::NewFeature also yielding "NewFeature".
Explicitly matching on the Unknown variant should
be avoided for two reasons:
- The inner data
UnknownVariantValueis 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
Completed
Failed
Modifying
Optimizing
Unknown(UnknownVariantValue)
Unknown. See the docs on this enum for the correct way to handle unknown variants.Unknown contains new variants that have been added since this code was generated.
Implementations§
source§impl VolumeModificationState
impl VolumeModificationState
sourcepub fn try_parse(value: &str) -> Result<Self, UnknownVariantError>
pub fn try_parse(value: &str) -> Result<Self, UnknownVariantError>
Parses the enum value while disallowing unknown variants.
Unknown variants will result in an error.
Trait Implementations§
source§impl AsRef<str> for VolumeModificationState
impl AsRef<str> for VolumeModificationState
source§impl Clone for VolumeModificationState
impl Clone for VolumeModificationState
source§fn clone(&self) -> VolumeModificationState
fn clone(&self) -> VolumeModificationState
1.0.0 · source§fn clone_from(&mut self, source: &Self)
fn clone_from(&mut self, source: &Self)
source. Read moresource§impl Debug for VolumeModificationState
impl Debug for VolumeModificationState
source§impl Display for VolumeModificationState
impl Display for VolumeModificationState
source§impl From<&str> for VolumeModificationState
impl From<&str> for VolumeModificationState
source§impl FromStr for VolumeModificationState
impl FromStr for VolumeModificationState
source§impl Hash for VolumeModificationState
impl Hash for VolumeModificationState
source§impl Ord for VolumeModificationState
impl Ord for VolumeModificationState
source§fn cmp(&self, other: &VolumeModificationState) -> Ordering
fn cmp(&self, other: &VolumeModificationState) -> 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 VolumeModificationState
impl PartialEq for VolumeModificationState
source§impl PartialOrd for VolumeModificationState
impl PartialOrd for VolumeModificationState
impl Eq for VolumeModificationState
impl StructuralPartialEq for VolumeModificationState
Auto Trait Implementations§
impl Freeze for VolumeModificationState
impl RefUnwindSafe for VolumeModificationState
impl Send for VolumeModificationState
impl Sync for VolumeModificationState
impl Unpin for VolumeModificationState
impl UnwindSafe for VolumeModificationState
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§default unsafe fn clone_to_uninit(&self, dst: *mut T)
default unsafe fn clone_to_uninit(&self, dst: *mut T)
clone_to_uninit)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