feat: ScheduleUpgradeNoHeightValidation for automated upgrades w/o gov proposal

[fedekunze]

Description

Implements a ScheduleUpgradeNoHeightValidation function for chains to schedule an automated upgrade (using the x/upgrade module) without having to go through a governance proposal.

This is beneficial to coordinate upgrades without having to manually download the new version, do the migration and restart the chain.

This is the procedure Evmos used for its automated upgrade.

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[alexanderbez]

This is for height-gated upgrade right? Like "Perform upgrade FOO and height H" without a gov prop?

This would still require a new binary for validators, but it doesn't have to be a coordinated download IIUC.

[ValarDragon]

I think we should just change the if plan.Height <= ctx.BlockHeight() { check to be if plan.Height < ctx.BlockHeight() {, and add a comment for why we allow it to be equal in this case.

(We allow for the possibility of chains to schedule upgrades in begin block of the same block, as a strategy for emergency hard fork recoveries)

[tac0turtle]

@fedekunze where did ScheduleUpgradeNoHeightValidation this pr is now comment and testing fixes

[fedekunze]

@marbar3778 we changed the height validation to accept plans scheduled at the current height

[assafmo]

Are there any docs for using it?

[danwt]

How can we use this? Any idea about

cosmos-sdk/x/upgrade/keeper/keeper.go

Lines 176 to 177 in b6c3756

	// NOTE: allow for the possibility of chains to schedule upgrades in begin block of the same block
	// as a strategy for emergency hard fork recoveries

// NOTE: allow for the possibility of chains to schedule upgrades in begin block of the same block
// as a strategy for emergency hard fork recoveries
if plan.Height < ctx.BlockHeight() {

We want to do an immediate hard fork

Thanks a lot!