fix(core): support tuple validation when schema items is an array (JSON Schema draft 07)

[Copilot]

validateProperty in params.ts did not handle the case where items is an array — the JSON Schema draft 07 tuple validation form. This caused false validation failures for schemas like Angular's @angular/build:unit-test, which uses tuple items to type reporter configurations:

{
  "type": "array",
  "minItems": 1,
  "maxItems": 2,
  "items": [
    { "anyOf": [{ "type": "string" }, { "enum": ["junit", "html", ...] }] },
    { "type": "object" }
  ]
}

Options like "reporters": [["junit", {"suiteName": "MyApp"}]] would incorrectly fail validation with "Property 'reporters' does not match the schema".

Changes

• validateProperty: when schema.items is an array, validates each element against its positional schema instead of passing the whole array as a schema
• minItems/maxItems enforcement: array length is now validated against minItems and maxItems constraints when present
• additionalItems support: rejects extra items when additionalItems: false; validates against the additionalItems schema when present; otherwise allows additional items (spec-compliant default)
• PropertyDescription type: added minItems, maxItems, additionalItems fields; narrowed items from any to PropertyDescription | PropertyDescription[]
• Type guards: added guards in coerceType and getPromptsForSchema where items.enum was accessed without accounting for the array form

Original prompt

---

This section details on the original issue you should resolve

<issue_title>Schema validation fails when items is a list.</issue_title>
<issue_description>### Current Behavior

In JSON Schema draft 07 (2018), the "items" property can be a list and must be validated using tuple validation.

The validateProperty util in packages/nx/src/utils/params.ts currently does not support this, causing validation to fail with the error that the property does not match the schema (but it does).

Expected Behavior

A schema using JSON Schema draft 07 like https://github.com/angular/angular-cli/blob/15794dc101fffd49818545c4ab015a3bf238b14a/packages/angular/build/src/builders/unit-test/schema.json must be successfully parsed by the NX parser.

OR

The parser must give a clear error message that it does not support the given schema.

GitHub Repo

https://github.com/Ionaru/schema7fail

Steps to Reproduce

In https://github.com/Ionaru/schema7fail:

1. Run npm install
2. Run nx test my-app

---

Clean repro:

1. Create an NX project with an Angular application
2. In project.json add:

    "test": {
      "executor": "@angular/build:unit-test",
      "options": {
        "reporters": [["junit", {"suiteName": "MyApp"}]]
      }
    }

3. Run nx test <app_name>

Nx Report

Node           : 24.14.0
OS             : win32-x64
Native Target  : x86_64-windows
npm            : 11.11.0

nx                     : 22.3.3
@nx/js                 : 22.3.3
@nx/eslint             : 22.3.3
@nx/workspace          : 22.3.3
@nx/angular            : 22.3.3
@nx/devkit             : 22.3.3
@nx/eslint-plugin      : 22.3.3
@nx/module-federation  : 22.3.3
@nx/playwright         : 22.3.3
@nx/plugin             : 22.3.3
@nx/rspack             : 22.3.3
@nx/vite               : 22.3.3
@nx/vitest             : 22.3.3
@nx/web                : 22.3.3
@nx/webpack            : 22.3.3
typescript             : 5.9.3

Failure Logs

NX   Property 'reporters' does not match the schema.
{
  "oneOf": [
    {
      "anyOf": [
        {
          "type": "string"
        },
        {
          "enum": [
            "default",
            "verbose",
            "dots",
            "json",
            "junit",
            "tap",
            "tap-flat",
            "html"
          ]
        }
      ]
    },
    {
      "type": "array",
      "minItems": 1,
      "maxItems": 2,
      "items": [
        {
          "anyOf": [
            {
              "type": "string"
            },
            {
              "enum": [
                "default",
                "verbose",
                "dots",
                "json",
                "junit",
                "tap",
                "tap-flat",
                "html"
              ]
            }
          ]
        },
        {
          "type": "object"
        }
      ]
    }
  ]
}'

Package Manager Version

No response

Operating System

• macOS
• Linux
• Windows
• Other (Please specify)

Additional Information

Linked to angular/angular-cli#32618</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes Schema validation fails when items is a list. #34631

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---

☁️ Nx Cloud last updated this comment at 2026-02-27 21:23:23 UTC

[Ionaru]

I would like to see tests that check these values:

• a: ['junit']: exactly minItems, should pass
• a: []: below minItems, should throw
• a: ['junit', { suiteName: 'MyApp' }, 'html']: above maxItems, should throw

[AgentEnder]

I would like to see tests that check these values:

• a: ['junit']: exactly minItems, should pass
• a: []: below minItems, should throw
• a: ['junit', { suiteName: 'MyApp' }, 'html']: above maxItems, should throw

@copilot

[Copilot]

I would like to see tests that check these values:

• a: ['junit']: exactly minItems, should pass...

Added all three test cases in 890177f, along with the actual minItems/maxItems enforcement in validateProperty (previously they were only defined in the type but not checked):

• a: ['junit'] — exactly minItems, passes ✓
• a: [] — below minItems, throws ✓
• a: ['junit', { suiteName: 'MyApp' }, 'html'] — above maxItems, throws ✓

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Important

At least one additional CI pipeline execution has run since the conclusion below was written and it may no longer be applicable.

Nx Cloud has identified a possible root cause for your failed CI:

Our e2e-web test encountered an infrastructure failure where the local npm registry at http://localhost:4873 is missing the @swc/jest package, causing a pnpm install failure. This is unrelated to the schema validation changes in this PR, which only modify params.ts validation logic. The test environment's registry needs to be restored before this e2e test can pass.

No code changes were suggested for this issue.

🔂 A CI rerun has been triggered by adding an empty commit to this branch.

View detailed reasoning on Nx Cloud ↗

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