[Deprecation] #[pallet:call_index] should be mandatory except in dev_mode

[gupnik]

Is there an existing issue?

• I have searched the existing issues

Experiencing problems? Have you tried our Stack Exchange first?

• This is not a support question.

Motivation

paritytech/substrate#11381 introduced call_index. However, it is still possible to create production pallets without specifying it.

Request

The expectation would be to make call_index mandatory in production. dev_mode can relax this requirement to support easy onboarding.

Solution

No response

Are you willing to help with this request?

Yes!

[KiChjang]

Huh, I thought @ggwpez made a PR that makes call_index mandatory already?

[bkchr]

It currently outputs a warning and that is a valid migration path.

[ggwpez]

The expectation would be to make call_index mandatory in production.

I would wait at least 6 months for that breaking change. And it could be a good candidate for trying #182

Current behaviour when no call_index is used:
dev mode: no print
standard mode: warning

[juangirini]

I would wait at least 6 months for that breaking change. And it could be a good candidate for trying #182

This issue is rather about introducing a new breaking change than deprecating a feature, not sure if it's the best candidate for #182

[ggwpez]

This one is the one that i actually meant: paritytech/substrate#12894. It added a "deprecate" warning if there is no call_index on a call.
So we are deprecating implicit call indices, and the final breaking change would be to disallow them.
I therefore think it fits as an example for the deprecation process, since it would otherwise break code of devs that are unaware.