Cleaning "common good" vs "system"

[bkontur]

Everything with paraId<2000 should be considered as system parachain.
(Here where also introduced system_parachain constants: #7005)

There are 3 possible places that are effected by change para<1000 -> para<2000.
So the main question is where to use "explicit paraIds" or relaxed para<2000?

How to setup:

---

Polkadot:

AllowExplicitUnpaidExecutionFrom

• actual: AllowExplicitUnpaidExecutionFrom<CollectivesOrFellows>
• update:
  • no change
  • AllowExplicitUnpaidExecutionFrom<SystemParachainsOrFellows>
    • SystemParachains -> paraId<2000
    • SystemParachains -> explicitly say which one (using constants)

ChildSystemParachainAsSuperuser

• actual: does not use for LocalOriginConverter
• update:
  • no change
  • add ChildSystemParachainAsSuperuser<SystemParachains>
    • SystemParachains -> paraId<2000
    • SystemParachains -> explicitly say which one (using constants)

TrustedTeleporters

• actual: (DotForAssetHub, DotForCollectives) (explicit)
• update:
  • no change (stay explicit - BH is comming here)
  • DotForSystemParachain based on paraId<2000 e.g. https://github.com/paritytech/cumulus/pull/2842/files#diff-53073f451405f5fdf3a02c595270a9fce3b0d5951122e0ad26f482a073019ad1R68-R79

---

Kusama:

AllowExplicitUnpaidExecutionFrom

• actual: AllowExplicitUnpaidExecutionFrom<IsChildSystemParachain<ParaId> (effected bychange in PR paraId<1000 -> paraId<2000)
• update:
  • no change (with this PR this will automatically include AssetHub, BridgeHub, Collectives, Encointer)
  • AllowExplicitUnpaidExecutionFrom<SystemParachains> -> explicitly say which one (using constants)

ChildSystemParachainAsSuperuser

• actual: ChildSystemParachainAsSuperuser<ParaId> (effected by change in PR paraId<1000 -> paraId<2000)
• update:
  • no change (with this PR this will automatically include AssetHub, BridgeHub, Collectives, Encointer)
  • ChildSystemParachainAsSuperuser<SystemParachains> -> explicitly say which one (using constants)

TrustedTeleporters

• actual: (KsmForAssetHub, KsmForEncointer) (explicit)
• update:
  • no change (stay explicit - BH is comming here)
  • KsmForSystemParachain based on paraId<2000 e.g. https://github.com/paritytech/cumulus/pull/2842/files#diff-53073f451405f5fdf3a02c595270a9fce3b0d5951122e0ad26f482a073019ad1R68-R79

---

Westend/Rococo:

the same as Kusama or relaxed more

---

• SiblingSystemParachainAsSuperuser - never used in Cumulus (effected by change in PR paraId<1000 -> paraId<2000)

---

• move NativeAssetFromSiblingSystemParachain to xcm-builder from here

[joepetrowski]

ChildSystemParachainAsSuperuser

Superusers should be explicitly listed IMO. Would not use < 2000 for that.

TrustedTeleporters

I am OK with using < 2000 for this.

[bkontur]

ChildSystemParachainAsSuperuser

Superusers should be explicitly listed IMO. Would not use < 2000 for that.

TrustedTeleporters

I am OK with using < 2000 for this.

cool, thank you, so I am going to change that,
and what about:

• Kusama AllowExplicitUnpaidExecutionFrom<IsChildSystemParachain - < 2000 or explicit?
• Polkadot AllowExplicitUnpaidExecutionFrom<CollectivesOrFellows> - should we add AssetHub/BridgeHub?

[joepetrowski]

For AllowExplicitUnpaidExecutionFrom, I am not 100% sure. I think paraId < 2000 is OK but lean toward keeping them explicit. It all comes down to whether the chain lets user construct their own XCM programs, and as long as we require governance to use xcm.send, it's only Collectives and Fellowship that can send a message with UnpaidExecution.

So I think either is OK, but perhaps @KiChjang can confirm, or we just keep it explicit for now.

[KiChjang]

Since both USER_INDEX_START and PUBLIC_INDEX_START are 2000, is there an actual difference between the two?

[KiChjang]

So the only problem that we may have in doing < 2000 is that we may accidentally whitelist a chain where we don't really know how its runtime code looks like, and I think Encointer then comes to mind. Being explicit is definitely the safest choice.

[bkontur]

So the only problem that we may have in doing < 2000 is that we may accidentally whitelist a chain where we don't really know how its runtime code looks like, and I think Encointer then comes to mind. Being explicit is definitely the safest choice.

@KiChjang
thank you, and would you mind if I copy out system_parachains constants from your PR here?

[KiChjang]

Yeah, it's just a matter of merging master depending on whether your PR or mine lands first.

[bkontur]

bot rebase

[paritytech-processbot]

Rebased