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