Proposal: Flatten `AllPallets` and similar types

[kianenigma]

Currently, all of the types generated via this macro are nested. For example, you have:

type AllPallets = (System, (Balances, Babe));

As far as I know, the main advantage of this is that we can use recursive implementations in some places. For example, PalletsInfoAccess introduced in https://github.com/paritytech/substrate/pull/10053/files is only implemented for (T1, T2), and there's no need to generate the code for longer tuples.

In fact, if we use only nested tuples, you can probably get away with impl_trait_for_tuple(2) for most items that are implemented for all pallets, such as OnInitialize etc.

The problem is: certain traits like OnInitialize are perfectly comprehensible both for T, and (T1, T2, T3), and (T1, (T2, T3)). But, certain traits like PalletInfoAccess are only comprehensible on individual items, i.e. T, but not on tuples.

And then you have an unfortunate scenario where you want to assert where T: PalletInfoAccess, and you know that each T does indeed implement PalletInfoAccess, but if demonstrated as a nested tuple, this does not work.

You can see a concrete example of this in what I am trying to do here: https://github.com/paritytech/substrate/pull/10174/files#diff-1c449417be9803cb427eed15d51557931141d47d0047561407f1651d319f7103R183

Lastly, in general, arguing about a flat array of tuples rather then nested is generally easier.

• [x] measure how slower it is to bump impl_trait_for_tuples to 100 instead of 30.

[kianenigma]

bot rebase

[paritytech-processbot[bot]]

Rebased

[kianenigma]

/cmd queue -c fmt $

[command-bot[bot]]

@kianenigma Could not find start of command (" $ ")

[kianenigma]

/cmd queue -c fmt

[command-bot[bot]]

@kianenigma Could not find start of command (" $ ")

[kianenigma]

/cmd queue -c fmt $ 1

[command-bot[bot]]

@kianenigma https://gitlab.parity.io/parity/mirrors/substrate/-/jobs/1726286 was started for your command "$PIPELINE_SCRIPTS_DIR/fmt.sh" 1. Check out https://gitlab.parity.io/parity/mirrors/substrate/-/pipelines?page=1&scope=all&username=group_605_bot to know what else is being executed currently.

Comment /cmd cancel 11-58e217d0-cfd8-4c51-94b8-464e4f4538b4 to cancel this command or /cmd cancel to cancel all commands in this pull request.

[command-bot[bot]]

@kianenigma Command "$PIPELINE_SCRIPTS_DIR/fmt.sh" 1 has finished. Result: https://gitlab.parity.io/parity/mirrors/substrate/-/jobs/1726286 has finished. If any artifacts were generated, you can download them from https://gitlab.parity.io/parity/mirrors/substrate/-/jobs/1726286/artifacts/download.

[kianenigma]

bot rebase

[paritytech-processbot[bot]]

Rebased

[paritytech-cicd-pr]

The CI pipeline was cancelled due to failure one of the required jobs. The job name - test-linux-stable The job logs - https://gitlab.parity.io/parity/mirrors/substrate/-/jobs/1740275

[kianenigma]

bot merge

[Polkadot-Forum]

This pull request has been mentioned on Polkadot Forum. There might be relevant details there:

https://forum.polkadot.network/t/polkadot-release-analysis-v0-9-41-v0-9-42/2828/1