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