#[non_exhaustive]pub enum ImportState {
Imported,
PendingImport,
Unknown(UnknownVariantValue),
}Expand description
When writing a match expression against ImportState, 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 importstate = unimplemented!();
match importstate {
ImportState::Imported => { /* ... */ },
ImportState::PendingImport => { /* ... */ },
other @ _ if other.as_str() == "NewFeature" => { /* handles a case for `NewFeature` */ },
_ => { /* ... */ },
}The above code demonstrates that when importstate represents
NewFeature, the execution path will lead to the second last match arm,
even though the enum does not contain a variant ImportState::NewFeature
in the current version of SDK. The reason is that the variable other,
created by the @ operator, is bound to
ImportState::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 ImportState::NewFeature is defined.
Specifically, when importstate represents NewFeature,
the execution path will hit the second last match arm as before by virtue of
calling as_str on ImportState::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
Imported
PendingImport
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 ImportState
impl ImportState
Source§impl ImportState
impl ImportState
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 ImportState
impl AsRef<str> for ImportState
Source§impl Clone for ImportState
impl Clone for ImportState
Source§fn clone(&self) -> ImportState
fn clone(&self) -> ImportState
1.0.0 · Source§fn clone_from(&mut self, source: &Self)
fn clone_from(&mut self, source: &Self)
source. Read moreSource§impl Debug for ImportState
impl Debug for ImportState
Source§impl Display for ImportState
impl Display for ImportState
Source§impl From<&str> for ImportState
impl From<&str> for ImportState
Source§impl FromStr for ImportState
impl FromStr for ImportState
Source§impl Hash for ImportState
impl Hash for ImportState
Source§impl Ord for ImportState
impl Ord for ImportState
Source§fn cmp(&self, other: &ImportState) -> Ordering
fn cmp(&self, other: &ImportState) -> 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 ImportState
impl PartialEq for ImportState
Source§impl PartialOrd for ImportState
impl PartialOrd for ImportState
impl Eq for ImportState
impl StructuralPartialEq for ImportState
Auto Trait Implementations§
impl Freeze for ImportState
impl RefUnwindSafe for ImportState
impl Send for ImportState
impl Sync for ImportState
impl Unpin for ImportState
impl UnwindSafe for ImportState
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§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