Severity trait & fix wildcard enum foot gun #207
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| // but not added to the match expression. | ||
| #[allow(dead_code)] | ||
| fn ensure_all_variants_handled(variant: Self) { | ||
| use LambdaRequestError::*; |
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Wildcard using the variants in an enum can be a gotcha. If someone were to remove a variant from the enum, the following match statement wouldn't catch it. Instead the variant that was removed would become a variable declaration for a catchall branch of the match. Like using a _.
| @@ -166,46 +135,46 @@ mod tests { | |||
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| #[test] | |||
| fn test_worse() { | |||
| use LambdaRequestError::*; | |||
| use LambdaRequestError as E; | |||
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If an enum has many variants and you want to avoid typing the name repeatedly, it is safer to use ... as to ensure the problem above can't happen.
| Self::RouterConnectionError => 2, | ||
| Self::AppConnectionUnreachable => 3, | ||
| Self::AppConnectionError => 4, | ||
| Self::ChannelErrorOther => 5, |
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Since the test ensuring all members are added to the ordered array had to list all members in a match, we may as well explicitly assign them a severity.
Another option would be to define the variants in order when defining the enum. Then you can cast the enum into a usize and compare them. But that also is easy to break by reordering the variant definitions or defining a new one in the wrong place.
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