Any optimization for When + Unless on same condition?

System Details

• FluentValidation version: 8.0

Issue Description

Hi,

I’m looking to define several rules for when a condition is met, and several other rules for when that same condition is not met.

To do that, my code is currently:

WhenAsync(CheckConditionAsync, () => { /* rules */ });
UnlessAsync(CheckConditionAsync, () => { /* rules */ });

Checking the condition is an I/O bound job and therefore asynchronous, so for performance reasons I’d like to avoid doing that twice. Is there some way of doing that with the current version of FluentValidation?

If there isn’t, but maybe also if there is, could it be possible to extend the overloads of When to include a 3rd parameter that would take another action for when the condition is not met? Or maybe to follow the fluent paradigm, make When return some interface that can chain an Otherwise method.

Thanks

[JeremySkinner]

Looks like this will be easier than I thought, will aim to get it into 8.1

First part of this is implemented in b897d3b. Now calls to When, WhenAsync, Unless and UnlessAsync on the root validator will cache the result of the predicate the first time it’s executed, so subsequent rules will recieve the cached value.

Will next look to see about chaining on an Otherwise method.

[JeremySkinner]

I’ll try and get to it for 8.2