#[non_exhaustive]pub enum RequiresRecreation {
Always,
Conditionally,
Never,
Unknown(UnknownVariantValue),
}
Expand description
When writing a match expression against RequiresRecreation
, 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 requiresrecreation = unimplemented!();
match requiresrecreation {
RequiresRecreation::Always => { /* ... */ },
RequiresRecreation::Conditionally => { /* ... */ },
RequiresRecreation::Never => { /* ... */ },
other @ _ if other.as_str() == "NewFeature" => { /* handles a case for `NewFeature` */ },
_ => { /* ... */ },
}
The above code demonstrates that when requiresrecreation
represents
NewFeature
, the execution path will lead to the second last match arm,
even though the enum does not contain a variant RequiresRecreation::NewFeature
in the current version of SDK. The reason is that the variable other
,
created by the @
operator, is bound to
RequiresRecreation::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 RequiresRecreation::NewFeature
is defined.
Specifically, when requiresrecreation
represents NewFeature
,
the execution path will hit the second last match arm as before by virtue of
calling as_str
on RequiresRecreation::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
Always
Conditionally
Never
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 RequiresRecreation
impl RequiresRecreation
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 RequiresRecreation
impl AsRef<str> for RequiresRecreation
source§impl Clone for RequiresRecreation
impl Clone for RequiresRecreation
source§fn clone(&self) -> RequiresRecreation
fn clone(&self) -> RequiresRecreation
1.0.0 · source§fn clone_from(&mut self, source: &Self)
fn clone_from(&mut self, source: &Self)
source
. Read moresource§impl Debug for RequiresRecreation
impl Debug for RequiresRecreation
source§impl Display for RequiresRecreation
impl Display for RequiresRecreation
source§impl From<&str> for RequiresRecreation
impl From<&str> for RequiresRecreation
source§impl FromStr for RequiresRecreation
impl FromStr for RequiresRecreation
source§impl Hash for RequiresRecreation
impl Hash for RequiresRecreation
source§impl Ord for RequiresRecreation
impl Ord for RequiresRecreation
source§fn cmp(&self, other: &RequiresRecreation) -> Ordering
fn cmp(&self, other: &RequiresRecreation) -> 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 RequiresRecreation
impl PartialEq for RequiresRecreation
source§fn eq(&self, other: &RequiresRecreation) -> bool
fn eq(&self, other: &RequiresRecreation) -> bool
self
and other
values to be equal, and is used
by ==
.source§impl PartialOrd for RequiresRecreation
impl PartialOrd for RequiresRecreation
source§fn partial_cmp(&self, other: &RequiresRecreation) -> Option<Ordering>
fn partial_cmp(&self, other: &RequiresRecreation) -> Option<Ordering>
1.0.0 · source§fn le(&self, other: &Rhs) -> bool
fn le(&self, other: &Rhs) -> bool
self
and other
) and is used by the <=
operator. Read moreimpl Eq for RequiresRecreation
impl StructuralPartialEq for RequiresRecreation
Auto Trait Implementations§
impl Freeze for RequiresRecreation
impl RefUnwindSafe for RequiresRecreation
impl Send for RequiresRecreation
impl Sync for RequiresRecreation
impl Unpin for RequiresRecreation
impl UnwindSafe for RequiresRecreation
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<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