#[non_exhaustive]
pub enum FailureHandlingPolicy {
DoNothing,
RollbackOnFailure,
Unknown(UnknownVariantValue),
}
Expand description
When writing a match expression against FailureHandlingPolicy
, 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 failurehandlingpolicy = unimplemented!();
match failurehandlingpolicy {
FailureHandlingPolicy::DoNothing => { /* ... */ },
FailureHandlingPolicy::RollbackOnFailure => { /* ... */ },
other @ _ if other.as_str() == "NewFeature" => { /* handles a case for `NewFeature` */ },
_ => { /* ... */ },
}
The above code demonstrates that when failurehandlingpolicy
represents
NewFeature
, the execution path will lead to the second last match arm,
even though the enum does not contain a variant FailureHandlingPolicy::NewFeature
in the current version of SDK. The reason is that the variable other
,
created by the @
operator, is bound to
FailureHandlingPolicy::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 FailureHandlingPolicy::NewFeature
is defined.
Specifically, when failurehandlingpolicy
represents NewFeature
,
the execution path will hit the second last match arm as before by virtue of
calling as_str
on FailureHandlingPolicy::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
DoNothing
RollbackOnFailure
Unknown(UnknownVariantValue)
Unknown
contains new variants that have been added since this code was generated.
Implementations§
Trait Implementations§
source§impl AsRef<str> for FailureHandlingPolicy
impl AsRef<str> for FailureHandlingPolicy
source§impl Clone for FailureHandlingPolicy
impl Clone for FailureHandlingPolicy
source§fn clone(&self) -> FailureHandlingPolicy
fn clone(&self) -> FailureHandlingPolicy
1.0.0 · source§fn clone_from(&mut self, source: &Self)
fn clone_from(&mut self, source: &Self)
source
. Read moresource§impl Debug for FailureHandlingPolicy
impl Debug for FailureHandlingPolicy
source§impl From<&str> for FailureHandlingPolicy
impl From<&str> for FailureHandlingPolicy
source§impl FromStr for FailureHandlingPolicy
impl FromStr for FailureHandlingPolicy
source§impl Hash for FailureHandlingPolicy
impl Hash for FailureHandlingPolicy
source§impl Ord for FailureHandlingPolicy
impl Ord for FailureHandlingPolicy
source§fn cmp(&self, other: &FailureHandlingPolicy) -> Ordering
fn cmp(&self, other: &FailureHandlingPolicy) -> Ordering
1.21.0 · source§fn max(self, other: Self) -> Selfwhere
Self: Sized,
fn max(self, other: Self) -> Selfwhere
Self: Sized,
source§impl PartialEq<FailureHandlingPolicy> for FailureHandlingPolicy
impl PartialEq<FailureHandlingPolicy> for FailureHandlingPolicy
source§fn eq(&self, other: &FailureHandlingPolicy) -> bool
fn eq(&self, other: &FailureHandlingPolicy) -> bool
self
and other
values to be equal, and is used
by ==
.source§impl PartialOrd<FailureHandlingPolicy> for FailureHandlingPolicy
impl PartialOrd<FailureHandlingPolicy> for FailureHandlingPolicy
source§fn partial_cmp(&self, other: &FailureHandlingPolicy) -> Option<Ordering>
fn partial_cmp(&self, other: &FailureHandlingPolicy) -> 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 FailureHandlingPolicy
impl StructuralEq for FailureHandlingPolicy
impl StructuralPartialEq for FailureHandlingPolicy
Auto Trait Implementations§
impl RefUnwindSafe for FailureHandlingPolicy
impl Send for FailureHandlingPolicy
impl Sync for FailureHandlingPolicy
impl Unpin for FailureHandlingPolicy
impl UnwindSafe for FailureHandlingPolicy
Blanket Implementations§
source§impl<Q, K> Equivalent<K> for Qwhere
Q: Eq + ?Sized,
K: Borrow<Q> + ?Sized,
impl<Q, K> Equivalent<K> for Qwhere
Q: Eq + ?Sized,
K: Borrow<Q> + ?Sized,
source§fn equivalent(&self, key: &K) -> bool
fn equivalent(&self, key: &K) -> bool
key
and return true
if they are equal.