InitChain does not respect InitialHeight

[joshklop]

Is there an existing issue for this?

• I have searched the existing issues

What happened?

When I call InitChain with an InitialHeight of 0 and call Commit, subsequent calls to Info return 1 as the LastBlockHeight.

Does the cosmos-sdk require InitialHeight to be set to 1? (I am using v0.47.2, but it appears this is the case in v0.50.3 as well). The ABCI appears to allow for both 0 and 1.

Possibly related: #16796

Cosmos SDK Version

v0.47.2

How to reproduce?

N/A

[facundomedica]

CometBFT allows InitialHeight to be 0 in InitChain but that does not mean that it allows a block with height 0 to exist.

See here:

• https://github.com/cometbft/cometbft/blob/825afaa6a4d33c4b54800d4ca595547d6e24c72e/spec/core/state.md?plain=1#L41-L42
• https://github.com/cometbft/cometbft/blob/825afaa6a4d33c4b54800d4ca595547d6e24c72e/internal/state/state.go#L52
• https://github.com/cometbft/cometbft/blob/825afaa6a4d33c4b54800d4ca595547d6e24c72e/types/genesis.go#L79-L81

And the Cosmos SDK does the same, accepts both 0 and 1, but will start always at 1:

cosmos-sdk/baseapp/abci.go

Lines 53 to 55 in 26c1db6

	if app.initialHeight == 0 { // If initial height is 0, set it to 1
	app.initialHeight = 1
	}

So starting at 0 or 1 will get you on block 1, but starting at any N > 1 will get you block N.