fix: use deliverState in prepare and processProposal at height 1 #14505
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facundomedica
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backport/v0.47.x
baseapp/abci.go
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| ctx := app.prepareProposalState.ctx | ||
| // Here we use deliverState on the first block given that we want to be able |
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Curious - why is the state with changes that InitChain made not available to the app?
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wdym "not available to the app"?
After InitChain, changes are not committed. They're technically staged/cached on the (cached) root multi-store. This isn't what prepareProposal state is based off of until Commit is called.
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InitChain initializes and applies changes (params, genesis and such) to deliverState, which is not persisted until Commit(): see here.
In Commit() deliverState is set to nil while the other states are set to the latest header (that's why we were seeing the previous block height in PrepareProposal before adding WithBlockHeight(req.Height) in this PR).
So PrepareProposal and ProcessProposal will always be seeing persisted state (from the previous produced block), except for the first block that we feed it with the genesis state. Also it's good to note that we shouldn't be making any persistable state changes during these stages.
Also BeginBlock is the one in charge of setting deliverState; except when we are at the first block: in that case we just want to update the context retaining any state changes made in InitChain. see here
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I see, thanks for the explanation. That makes sense.
Random alternative thoughts:
- Would it be better to dedicate height == 1 to
InitChainonly? meaning that the at height 1, CosmosSDK just runsInitChainand then callsCommit. No special logic to override the ctx state to be thedeliverStatewhich has not been committed. My main reasoning around this is if there would be any weird behavior for thePrepareProposalto be based off of state that has not been committed to state. - Similarly, is it possible to introduce some special height 0 that does the
InitChainandCommitonly
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[Cosmos SDK] Kudos, SonarCloud Quality Gate passed!
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@facundomedica lets resolve the merge conflict and get this merged 🙌 |
) (cherry picked from commit 3fc4f33) # Conflicts: # CHANGELOG.md
Description
Ref: #14446
Audit: #13951
Issue: State couldn't be queried on PrepareProposal and ProcessProposal on the first block, so you couldn't get params or get stuff changed during the InitChain (mainly genesis).
We now use a cached context from
deliverStateduring the first block. This allows us to query any state changed duringInitChain(which is done ondeliverState).After the first block we use
prepareProposalStateorprocessProposalState, asdeliverStateis not initialized and there's no state being changed prior toPrepareProposal(in the ABCI flow there's no step prior after the first block is produced).A check for invalid height was added to
PrepareProposalas it's invalid to pass anything < 1. I don't see this happening in real life but there were some invalid tests.Author Checklist
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