fix(baseapp): sort res.Validators before comparing in InitChain

[damiannolan]

Description

Sort the validators returned from the app in InitChain before comparing with those in InitChainRequest.

Caught in genesis export test here: https://github.com/cosmos/ibc-go/actions/runs/12123056947/job/33797947420?pr=7587

Nodes fail to restart after genesis export and restart.

ERR failure when running app err="error during handshake: error on replay: genesisValidators[0] != req.Validators[0]

Noticed that on v0.50 both validator sets are sorted, so think this was accidentally removed at some point in v0.52 dev.
https://github.com/cosmos/cosmos-sdk/blob/v0.50.10/baseapp/abci.go#L118-L119

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Summary by CodeRabbit

• Bug Fixes
  • Improved the validation process for genesis validators during initialization to ensure consistent comparison regardless of order.
  • Enhanced error handling for mismatched validator lengths and individual validator discrepancies.

[coderabbitai]

📝 Walkthrough

Walkthrough

The changes in this pull request involve a modification to the InitChain method of the BaseApp class located in baseapp/abci.go. The primary change is the addition of a sorting step for the res.Validators slice to ensure both request and response validators are sorted before comparison. This adjustment aims to maintain consistency in validating the equality of genesis validators, preventing mismatches due to differing orderings. The error handling logic remains unchanged, and no other methods are affected.

Changes

File	Change Summary
baseapp/abci.go	Modified InitChain method to add sorting for res.Validators for consistent validation of genesis validators. Error handling logic remains unchanged.

Possibly related PRs

• fix(runtime/v2): return genesis val updates #22729: The changes in this PR involve modifications to the initGenesis method, which is closely related to the InitChain method in the main PR, as both deal with the initialization of validators during the genesis phase.

Suggested labels

C:server/v2, C:server/v2 appmanager

Suggested reviewers

• kocubinski
• facundomedica
• auricom
• hieuvubk
• tac0turtle
• sontrinh16

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📜 Recent review details

Configuration used: .coderabbit.yml
Review profile: CHILL

📥 Commits

Reviewing files that changed from the base of the PR and between eb3bf8b and 8c76c40.

📒 Files selected for processing (1)

• baseapp/abci.go (1 hunks)

🧰 Additional context used

📓 Path-based instructions (1)

baseapp/abci.go (1)

Pattern **/*.go: Review the Golang code for conformity with the Uber Golang style guide, highlighting any deviations.

🔇 Additional comments (1)

baseapp/abci.go (1)

124-124: LGTM: Restoring validator sorting ensures consistent genesis export.

The addition of sort.Sort(abcitypes.ValidatorUpdates(res.Validators)) is correct and necessary. This change restores the sorting behavior that was present in v0.50 but inadvertently removed in v0.52. By sorting both request and response validators before comparison, we ensure consistent ordering and prevent false mismatches during genesis export and node restart.

Let's verify the validator sorting implementation:

✅ Verification successful

Let me gather more context about the validator comparison logic:

---

Based on the comprehensive analysis of the codebase, I can now generate the final response:

Sorting validators in InitChain is correct and necessary for deterministic validation

The sorting of both req.Validators and res.Validators in InitChain is essential for deterministic validation during genesis export. The implementation is consistent with the codebase's validator handling patterns:

• The sorting ensures consistent ordering before comparison, which is critical for deterministic validation during genesis export and node restart
• The code follows the same pattern used in other validator update operations throughout the codebase
• The change restores important functionality that was present in v0.50 and needed to be brought back

🏁 Scripts executed

The following scripts were executed for the analysis:

Script:

#!/bin/bash
# Description: Check if validator sorting is consistently implemented across the codebase
# Look for other instances where ValidatorUpdates are compared to ensure consistent sorting

# Search for validator comparison patterns
ast-grep --pattern 'proto.Equal($v1, $v2)' 

# Search for validator sorting patterns
rg 'sort.*ValidatorUpdates'

Length of output: 218

---

Script:

#!/bin/bash
# Search for the InitChain method implementation and surrounding context
ast-grep --pattern 'func (app $_) InitChain($_) $_' -A 20

# Look for validator update related code
rg -A 5 "ValidatorUpdates?" 

Length of output: 66678

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[github-actions]

@damiannolan your pull request is missing a changelog!

[julienrbrt]

I had to look twice, they look identical 😅, that's probably how it got removed :D