msg(exec) macro conditional on feature / config

[maurolacy]

It would be nice if the msg(exec) macro could be enabled based on a feature or config option.

That is, something like #[cfg(test, msg(exec))], or a similar syntax.

This would be very useful to add handlers that are only available / used for testing.

See
https://github.com/osmosis-labs/mesh-security/blob/70872078c80b8019f2da6220b47222dab753baad/contracts/provider/external-staking/src/contract.rs#L230C6-L244

for an example where this would be useful.

[hashedone]

First of all - I am pretty sure something is wrong with the testing approach here. My hot take: having test-only API is a code smell. In the test, you want to verify states which are possible in the real world, so you should be able to achieve the tested state with a non-test-only API.

What I assume you are doing here is making some shortcuts to achieve some state you assume should be possible with some flow, but you don't include the fact that achieving such a state might lead to additional changes happening around which our test does not consider. And the worst part of that is - maybe now those additional things do not happen, but it might change in the future, and you will not consider those changes because your test still uses the shortcut.

So this is a reason why I am strongly against providing a special solution for that.

Now the proper answer - the solution already exists in Rust itself - it is a cfg_attr. In your case: #[cfg_attr(test, msg(exec))] - however I still strongly advice to not structure test this way.

[maurolacy]

First of all - I am pretty sure something is wrong with the testing approach here. My hot take: having test-only API is a code smell. In the test, you want to verify states which are possible in the real world, so you should be able to achieve the tested state with a non-test-only API.

I know. We're currently forced to do this, because of limitations of the testing framework (no IBC support in mt).

...
Now the proper answer - the solution already exists in Rust itself - it is a cfg_attr. In your case: #[cfg_attr(test, msg(exec))] - however I still strongly advise to not structure test this way.

When I do this it compiles, but then fails when compiling tests:

$ cargo test
...
error: cannot find attribute `msg` in this scope
   --> contracts/provider/external-staking/src/contract.rs:233:22
    |
233 |     #[cfg_attr(test, msg(exec))]

Is there a way around it, perhaps qualifying or importing the required macro?

[maurolacy]

Re-opening, as after macro expansion we can confirm the cfg_attr(test, msg(exec)) is not being processed / understood by the contract macro.

[hashedone]

As I am not happy about this testing approach, I still see value in gating sylvia attributes with features using cfg_attr - we should at least refine where there is a problem and document it.