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