Feat/add support for _varchar

[Jordan-M-Young]

The goal of this PR is to solve the issue: Add support for _varchar #480. This issue centers around connectorx panicking when interacting with tables containing a varchar[] type.

To solve this, I added:

• a VarcharArray type in the various enums in connectorx/src/sources/postgres/typesystem.rs
• a Utf8Array type in the various enums in connectorx/src/destinations/arrow2/typesystem.rs
• a mapping between VarcharArray and Utf8Array in connectorx/src/transports/postgres_arrow2.rs
• implemented the ArrowAssoc traint for Option<Vec> and Vec in connectorx/src/destinations/arrow2/arrow_assoc.rs
• added _varchar/varchar[] data to scripts/postgres.sql
• added a test for _varchar/varchar[] compatibility with postgres/polars in connectorx/tests/test_polars.rs

Excited to hear feedback, make edits, and hopefully merge this PR into the project! This is my first ever OS contribution so I apologize for any rookie mistakes in advance!

[wangxiaoying]

Thanks @Jordan-M-Young for the PR! It looks good in general, and I left a minor comment. Also can you run cargo fmt to format the code in order to resolve the CI error?

[Jordan-M-Young]

@wangxiaoying Thanks for taking a look at my PR! I just committed the requested edits (removing src/macro.rs changes and running cargo fmt)

Hopefully that will fix the CI pipeline! Looking forward to seeing this merged!!

[Jordan-M-Young]

Hey @wangxiaoying I see that the testing stage of the CI pipelines failed on this latest check. I ran

cargo clean && just test locally and my test passes. I am using an updated version of the postgres.sql script to populate my dev postgres instance could that be the issue?

Have a nice weekend!

[wangxiaoying]

Hi @Jordan-M-Young , yeah I think that's probably the issue. We use postgres official docker hub image in our CI. You can use it to test locally and see whether your insert value sql can be run on it.

Have a nice weekend to you too : )

[Jordan-M-Young]

@wangxiaoying You were right, there was a typo in postgres.sql causing insert operation to fail. Hopefully its fixed now!

[wangxiaoying]

Thank you @Jordan-M-Young !

[auyer]

This is really cool! Thanks @Jordan-M-Young !
@wangxiaoying , do you mind generating a new Release, or rc? 😄

[Jordan-M-Young]

Thanks for your help with this @wangxiaoying ! Looking forward to contributing more in the future.