Add .default() as column definition modifier

[3commascapital]

• add hook for use in schema
• use default for method name
• write tests to verify that default value is used

[0xOlias]

Couple general notes:

• Per the discussion here I propose we go with .default() over .defaultTo()
• I'm not sure if this is handled yet, but adding .default to a column should automatically/implicitly make it optional. Perhaps we should validate against including both .optional() and .default() to a column?

[3commascapital]

ah, thanks for linking. forgot to do that. regarding your points:

• if we do not mind the js .default export pattern and wish to distinguish from this pattern, i am ok with that. That possible conflict was the only one I had in mind.
• I don't know that it should actually. Optional only denotes nullability, which should still be possible to do even if you started with a non null value. In other words, when I first insert, I don't have a value, the database will use the default value for me, but I should be able to turn that into null later on or use null during insertion.

[0xOlias]

Re 1: I think it's fine - this is being used in a context rather distant from a module export. Fwiw Drizzle uses .default as well.

Re 2: Ah yes, my mistake - you're right. The interesting case is: if a column has a default and is NOT optional, it should still be optional when inserting or updating records of that table (but not when selecting). I'm not sure how well our existing type system is set up to handle this, cc @kyscott18

[3commascapital]

💯

[3commascapital]

should (probably) be addressable in this pr

[kyscott18]

Nice work - reviewed most of this. I think we need to add extra logic to database/sqlite/service.ts and schema/infer.ts but looking good.

[kyscott18]

Why is this needed

[3commascapital]

without this coersion, i get the following error during typecheck:

packages/core build: src/schema/schema.ts(112,7): error TS4023: Exported variable 'P' has or is using name 'DefaultTo' from external module "~/ponder/packages/core/src/schema/columns" but cannot be named.