fix(schema): drop constructor defaults when deriving update schemas

[MindfulLearner]

Problem

const Person = Schema.Struct({
  name: Schema.String,
  age: Schema.Finite.pipe(Schema.propertySignature, Schema.withConstructorDefault(() => 0))
})

const UpdatePerson = Schema.Struct({
  name: Schema.optional(Schema.String),
  age: Schema.Finite.pipe(Schema.optional, Schema.withConstructorDefault(() => 0))
})

// current
UpdatePerson.make({ name: "test" }) // => { name: "test", age: 0 }

// desired
UpdatePerson.make({ name: "test" }) // => { name: "test" }

Any field carrying withConstructorDefault gets auto-filled by .make() when omitted, by design. Struct.omit/pick just makes it easy to inherit one from an entity schema without noticing; writing the field by hand on an Update schema hits the same behavior. Clients call .make() implicitly on .mutate(), so the default silently overwrites the value the caller left untouched.

Fix

const UpdatePerson = Schema.Struct(
  Struct.map(Struct.omit(Person.fields, [] as const), S.dropConstructorDefault)
)

UpdatePerson.make({ name: "test" }) // => { name: "test" }

• dropConstructorDefault: a Struct.Lambda that removes a field's constructor default. Replaces the earlier combined omitConstructorDefaults helper.
• makeExactOptional now drops constructor defaults automatically.

Out of scope (follow-up candidates, not blocking this PR)

• shortcut helper combining omit + map(dropConstructorDefault) in one call
• dropping decoding defaults (only constructor defaults are handled here)

Related: https://github.com/macs-holding/configurator/pull/851
Discussion: https://discord.com/channels/1083767712431480922/1521940676416241745

[pkg-pr-new]

Open in StackBlitz

@effect-app/cli

npm i https://pkg.pr.new/effect-app/libs/@effect-app/cli@814

effect-app

npm i https://pkg.pr.new/effect-app/libs/effect-app@814

@effect-app/eslint-codegen-model

npm i https://pkg.pr.new/effect-app/libs/@effect-app/eslint-codegen-model@814

@effect-app/eslint-shared-config

npm i https://pkg.pr.new/effect-app/libs/@effect-app/eslint-shared-config@814

@effect-app/infra

npm i https://pkg.pr.new/effect-app/libs/@effect-app/infra@814

@effect-app/vue

npm i https://pkg.pr.new/effect-app/libs/@effect-app/vue@814

@effect-app/vue-components

npm i https://pkg.pr.new/effect-app/libs/@effect-app/vue-components@814

commit: 1f18526

[patroza]

Inheriting the behaviors of fields is desired. In what case are you considering this undesirable or a "bug"?
This pr / issue lacks motivation.

If you need a tool to strip withConstructorDefault then i would suggest to make a helper that just does that so you can simply mapFields(flow(Struct.omit(..), stripConstructorDefaults))

[patroza]

@MindfulLearner update/resolve reviews when you apply changes