feat(planetscale): check unchangeable props with adopt: true

[mmkal]

Hi! At https://github.com/iterate/iterate we use adopt: true with planetscale for our DB created by hand. It'd be good to still be able to kinda specify the database region as an assertion, since the impacts of the wrong region are very big.

This eliminates the risk of setting region: "aws-eu-west-2" and happily and confidently going ahead with a database that's in the wrong continent without realising. (It doesn't fix it, but it at least fails the deployment and prompts us to fix it).

Also validates kind and arch on adopt. These are also immutable after creation and were previously silently trusted from props (so you could adopt a mysql db while claiming it's postgresql, and downstream code would act on the wrong kind).

Branch region is also covered: branches can be in different regions from the database, so the Branch resource now accepts region and validates it on adopt too. actualRegion is exposed in both Database and Branch outputs.

// Catches wrong-region adopt
const db = await Database("my-db", {
  name: "os-production",
  adopt: true,
  region: { slug: "aws-eu-west-2" }, // throws if actual region differs
  kind: "postgresql", // throws if actual kind differs
  arch: "x86", // throws if actual arch differs
  clusterSize: "PS_10",
});

console.log(db.actualRegion.slug); // "aws-eu-west-2"

[Mkassabov]

I know this is marked as a draft but I left a few quick comments.

This is a very valuable change and makes me want to re-discuss with the team what adoption looks like in the next version of alchemy so we don't run into problems like this again. So thank you!

Feel free to @ me when you feel this is done and I can review & merge.

[mmkal]

@Mkassabov thanks for the feedback - I've addressed your comments and marked ready for review