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