types(document): add id virtual getter by default to HydrateDocument<> if TOverrides is Record<string, never>

[vkarpov15]

Fix #15900

Summary

An unintentional backwards breaking change in Mongoose 9 when we removed id as a property on Document: people who use new Schema<RawDocType>() no longer get the id virtual by default. Works fine with automatic inference new Schema(), but once you override RawDocType the id virtual goes away.

This PR adds the id virtual if TOverrides is Record<string, never>, which is the default. Unless id: false option is set, or the RawDocType has an id property.

Examples

[Copilot]

Pull request overview

This PR fixes a backwards compatibility issue in Mongoose 9 where users who explicitly specify a raw document type using new Schema<RawDocType>() no longer get the default id virtual getter, which was unintentionally removed when id was removed as a property on Document.

Key Changes:

• Modified the HydratedDocument type to add the id virtual by default when TOverrides is Record<string, never> (the default value)
• Added type tests to verify the id virtual is available when using model<T>() with explicit generics, and that it respects existing id properties

Reviewed changes

Copilot reviewed 1 out of 2 changed files in this pull request and generated 2 comments.

File	Description
types/index.d.ts	Added AddDefaultId<HydratedDocPathsType, {}, TSchemaOptions> to the HydratedDocument type when TOverrides is the default empty record, ensuring the id virtual getter is included by default
test/types/document.test.ts	Added test function to verify the id virtual is available with explicit generic types and that it doesn't override existing id properties

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[hasezoey]

LGTM, aside from the test name