feat: add iter->status() check for loop iterators

[LindaSummer]

Issue

close #2200

Proposed Changes

• add iterator status error handler after iteration.

Comment

1. Some iterators checked Valid() after loop so I didn't add status validation.
   Here is rocksdb's document.

If there is no error, the status is Status::OK(). If the status is not OK, the iterator will be invalidated too. In another word, if Iterator::Valid() is true, status() is guaranteed to be OK() so it's safe to proceed other operations without checking status().

2. Please correct me if I need add some more logic of error handler, or the error message I generated is not suitable.
   Thanks very much!

[git-hulk]

LGTM, one comment inline.

[LindaSummer]

Hi @git-hulk ,

I find it seems hard to create unit tests for the error handling code and pass sonarcloud coverage.
Could you give me some suggestions?

Best Regards,
Edward

[git-hulk]

@LindaSummer That’s fine for this PR, no need to add the extra tests.

[sonarcloud]

Quality Gate failed

Failed conditions
33.7% Coverage on New Code (required ≥ 50%)

See analysis details on SonarCloud

[LindaSummer]

Hi @git-hulk ,

Got it! 😊
Thanks very much for your help and patience!

Best Regards,
Edward