Fix incorrect caching of case-insensitivity

[pirj]

Motivation / Background

This Pull Request has been created to prevent multiple queries checking column insensitive comparison capability.

Detail

false values would not cache with ||=, and begin would run each time.
Instead, checking if a key for a certain column is present in the cache prevents running the query again.

Checklist

Before submitting the PR make sure the following are checked:

• This Pull Request is related to one change. Changes that are unrelated should be opened in separate PRs.
• Commit message has a detailed description of what changed and why. If this PR fixes a related issue include it in the commit message. Ex: [Fix #issue-number]
• Tests are added or updated if you fix a bug or add a feature.
• CHANGELOG files are updated for the changed libraries if there is a behavior change or additional feature. Minor bug fixes and documentation changes should not be included.
• CI is passing.

[byroot]

Suggested change

	@case_insensitive_cache[column.sql_type] =
	@case_insensitive_cache.fetch(column.sql_type) do
	@case_insensitive_cache.fetch(column.sql_type) do
	@case_insensitive_cache[column.sql_type] =

[pirj]

Something fishy is going on here.

With this suggested change, we're basically getting rid of a redundant c[t] = c[t] when there's a t key in c already.

I'm uncertain if the same conditions as in "do not modify the array during iteration" apply here, but I'd rather keep on the safe side.

I'll revert this change if you don't object.

[byroot]

No it should be fine. I can have a look at the CI failure in a bit.

[byroot]

Ah, I think it's missing a begin/end

[byroot]

The code looks correct to me now, please squash the two commits though.

However I need to have a look at that CI failure, I don't know 100% it's unrelated.

[byroot]

Manually merged as b39050e.

Thanks.

[pirj]

Thank you, @byroot !