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