ci: improve error checking (errcheck linter)

[julienrbrt]

Description

Implements part of #7258

Check some of currently unchecked errors.

• baseapp
• client
• codec
• crypto
• server
• simapp
• snapshots
• store
• testutil
• types
• modules

---

Author Checklist

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please add links to any relevant follow up issues.

I have...

• included the correct type prefix in the PR title
• added ! to the type prefix if API or client breaking change
• targeted the correct branch (see PR Targeting)
• provided a link to the relevant issue or specification
• followed the guidelines for building modules
• included the necessary unit and integration tests
• added a changelog entry to CHANGELOG.md
• included comments for documenting Go code
• updated the relevant documentation or specification
• reviewed "Files changed" and left comments if necessary
• confirmed all CI checks have passed

Reviewers Checklist

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your handle next to the items reviewed if you only reviewed selected items.

I have...

• confirmed the correct type prefix in the PR title
• confirmed ! in the type prefix if API or client breaking change
• confirmed all author checklist items have been addressed
• reviewed state machine logic
• reviewed API design and naming
• reviewed documentation is accurate
• reviewed tests and test coverage
• manually tested (if applicable)

[robert-zaremba]

Thanks for doing this. I started similar work 1.5 year ago.
I suggest we do a partial merge, to avoid future conflicts. How about that? I think you can add nested .golangci.yml to enable errcheck in subdirectories.

[julienrbrt]

Thanks for doing this. I started similar work 1.5 year ago. I suggest we do a partial merge, to avoid future conflicts. How about that? I think you can add nested .golangci.yml to enable errcheck in subdirectories.

Yes I've seen 😄 Do you mean merging your branch in this PR or rebasing with master?

[robert-zaremba]

You can merge my branch or manually copy some stuff from it.

I meant that you don't need to finish everything to merge it into master - if the process will take too long we can break the task into 2 PRs - if that helps.

[julienrbrt]

The PR makes me think of #11215 ; not sure if the linter should be enforced (as we may need to add many nolint comments).
However, I believe verifying the error checking across the codebase still has an added value.

Splitting this PR as per above comment.

[alexanderbez]

Skimmed through it. Most error handling spots looks good to me. I left a comment on a few. Mainly just want to make sure we're exiting or panicing where/when we need to, to be consistent with the rest of the logic.

[likhita-809]

lgtm

[fedekunze]

utACK 💯 thanks @julienrbrt!