0586da7167
Unfortunately, since the Batch wrapper was changed to have a generic error type, when wrapping it in another Service, nothing constrains the error type, so we have to specify it explicitly to avoid an inference hole. This is pretty unergonomic -- from the compiler error message it's very unintuitive that the right fix is to change `Batch::new` to `Batch::<_, _, SomeError>::new`. The options are: 1. roll back the changes that make the error type generic, so that the error type is a concrete type; 2. keep the error type generic but hardcode the error in the default constructor and add an additional code path that allows overriding the error. However, there's a further issue with generic errors: the error type must be Clone. This problem comes from the fact that there can be multiple Batch handles that have to share access to errors generated by the inner Batch worker, so there's not a way to work around this. However, almost all error types aren't Clone, so there are fairly few error types that we would be swapping in. This suggests that in case (2) we would be maintaining extra code to allow generic errors, but with restrictive enough generic bounds to make it impractical to use generic error types. For this reason I think that (1) is a better option. |
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| .. | ||
| error.rs | ||
| future.rs | ||
| layer.rs | ||
| lib.rs | ||
| message.rs | ||
| service.rs | ||
| worker.rs | ||