Use chain_spec_path to detect asset hub polkadot

[svyatonik]

There's no way now to use polkadot-parachain with --chain=asset-hub-polkadot-local, so we need to use chain spec path. But zombienet only uses the chain parameter to detect polkadot AH and generate proper keystore files (for which workaround is to explicitly specify aura_ed in keystore_key_types) + properly modify chain validators in spec (for which there's no easy workaround).

[pepoviola]

Hi @svyatonik thanks for your contribution, I think this is related to the new runtimes repo right? We add support for using a custom external tool to build the chain-spec here.
If this is the case you can follow the instructions from #1449 (comment) and use the chain-spec-generator tool from the runtimes repo.

Please let me know if this cover your case?
Thanks!

[svyatonik]

Nope, that doesn't solve our problem :) I'm also using that tool, but because there were no support of chain_spec_generator for parachains, I had to write a script that emulated old polkadot-parachain behavior and either starts chain-spec-generator or the actual polkadot-parachain depending on args.

The "core" problem is that the Asset Hub Polkadot is a special case and when zombienet is generating/patching chain spec for this chain, it does two things:

1. it writes ed keys for Aura to the keystore;
2. and yet it writes address, associated with ed key to the chain spec (validators set).

Without those two points, the local Polkadot Asset Hub simply won't produce blocks (as I said in description, there's a workaround for (1), but no easy workaround for (2)). Before fellowship repo, the polkadot-parachain was supporting the --chain=asset-hub-polkadot-local argument && everyone used that. But now with AH moved to fellowship, we have to provide external chain spec, so it doesn't work anymore. So the parachain.chain here and parachain.chain here are undefined and this hack doesn't work. So what I suggest is to also check the chain_spec_path there, where we could actually use the asset-hub-polkadot name to trigger it.

[pepoviola]

Hi @svyatonik, thanks for the reply 👍 . @NachoPal add system parachains in this pr polkadot-fellows/runtimes#81 but isn't yet merged, I will merge this and then we can review if the chain-spec-generator works as expected as external generator set in chain_spec_command.
Again, thanks for your contribution!!