ValidationPipe-specific options are included in validatorOptions and trigger classToPlain

[coxxny]

Is there an existing issue for this?

• I have searched the existing issues

Current behavior

When exceptionFactory, validatorPackage, or transformerPackage is passed to ValidationPipe, the option is included in the remaining validatorOptions.

As a result, specifying any one of them adds a second key alongside the default forbidUnknownValues value. This makes the following condition unexpectedly evaluate to true.

const shouldTransformToPlain =
  Object.keys(this.validatorOptions).length > 1;

classToPlain is therefore executed even when no actual ValidatorOptions were specified.

Minimum reproduction code

https://github.com/coxxny/nest-validation-pipe-class-to-plain-repro/tree/import-fixed-package

Steps to reproduce

1. Clone the reproduction repository.
2. Run npm install.
3. Run npm test.
4. Observe that the baseline subtest passes, while the subtests using only exceptionFactory, validatorPackage, or transformerPackage fail.
5. In each failing subtest, the secret property is removed because classToPlain was executed.

Expected behavior

exceptionFactory, validatorPackage, and transformerPackage should not be included in this.validatorOptions.

When one of these options is specified without any actual ValidatorOptions, classToPlain should not be executed and the pipe should return the original plain value.

NestJS version

11.1.28

Packages versions

    "@nestjs/common": "11.1.28",

Node.js version

24.17.0

In which operating systems have you tested?

• macOS
• Windows
• Linux

Other

No response

[kamilmysliwiec]

lets track this here #17399