Fix invalid storage dir configurations lead to unexpected behavior (#4105)

[ti-chi-bot]

This is an automated cherry-pick of #4105

What problem does this PR solve?

Issue Number: close #4093

Problem Summary:
If the user set the config file with

[storage]
[storage.main]
dir = "/data0/db"
# Should be: dir = ["/data0/db"]
[storage.raft]
dir = "/data0/db"
# Should be: dir = ["/data0/db"]

If storage.main.dir,storage.latest.dir,storage.raft.dir is a string instead of string-array, TiFlash now considers it is an empty array without any warning/exception, which leads to unexpected behavior

What is changed and how it works?

Check whether storage.main.dir, storage.latest.dir, storage.raft.dir is string array or not. If not, throw an exception and stop tiflash.

Check List

Tests

• Unit test
• Integration test
• Manual test (add detailed scripts or steps below)
• No code

Side effects

• Performance regression: Consumes more CPU
• Performance regression: Consumes more Memory
• Breaking backward compatibility

Documentation

• Affects user behaviors
• Contains syntax changes
• Contains variable changes
• Contains experimental features
• Changes MySQL compatibility

Release note

Fix the bug that invalid storage dir configurations lead to unexpected behavior

[ti-chi-bot]

[REVIEW NOTIFICATION]

This pull request has been approved by:

• CalvinNeo
• JaySon-Huang

To complete the pull request process, please ask the reviewers in the list to review by filling /cc @reviewer in the comment.
After your PR has acquired the required number of LGTMs, you can assign this pull request to the committer in the list by filling /assign @committer in the comment to help you merge this pull request.

The full list of commands accepted by this bot can be found here.

Reviewer can indicate their review by submitting an approval review.
Reviewer can cancel approval by submitting a request changes review.

[CalvinNeo]

LGTM

[JaySon-Huang]

/run-all-tests

[JaySon-Huang]

/run-all-tests

[JaySon-Huang]

/run-all-tests

[JaySon-Huang]

/run-all-tests

[JaySon-Huang]

/merge

[ti-chi-bot]

@JaySon-Huang: It seems you want to merge this PR, I will help you trigger all the tests:

/run-all-tests

You only need to trigger /merge once, and if the CI test fails, you just re-trigger the test that failed and the bot will merge the PR for you after the CI passes.

If you have any questions about the PR merge process, please refer to pr process.

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the ti-community-infra/tichi repository.

[ti-chi-bot]

This pull request has been accepted and is ready to merge.

Commit hash: ef30a19