🐛 Bug Report: Regression scaffolder action with combided zod schemas fails validation

[Andy2003]

📜 Description

Given the schema (adjusted from tests):

      createTemplateAction({
        id: 'jest-zod-validated-action',
        description: 'Mock action for testing',
        handler: fakeActionHandler,
        supportsDryRun: true,
        schema: {
          input: z
            .object({
              foo: z.number(),
            })
            .and(z.object({ bar: z.string() })),
        },
      })

The following input:

{ foo: 1, bar: 'bar' }

results in an validation error:

InputError: Invalid input passed to action jest-zod-validated-action, instance does not match allOf schema [subschema 0] with 1 error[s]:, instance is not allowed to have the additional property "bar", instance does not match allOf schema [subschema 1] with 1 error[s]:, instance is not allowed to have the additional property "foo"

This is because the zod schema is converted to the following JsonSchema:

{
  "allOf": [
    {
      "type": "object",
      "properties": {
        "foo": {
          "type": "number"
        }
      },
      "required": [
        "foo"
      ],
      "additionalProperties": false
    },
    {
      "type": "object",
      "properties": {
        "bar": {
          "type": "string"
        }
      },
      "required": [
        "bar"
      ],
      "additionalProperties": false
    }
  ],
  "$schema": "http://json-schema.org/draft-07/schema#"
}

The Problem is, that the additionalProperties in both allOf-schemas resullts in failing each separate sub-schema validation. This seems to be a common problem in JsonSchema-Validation.

To fix such issues, one can use nonstrict() on each of the combined zod schemas, like:

z
    .object({
        foo: z.number(),
    })
    .nonstrict()
.and(
    z.object({ bar: z.string() })
      .nonstrict()
)

But with this in place, the user can add additional keys to the input, like:

{ foo: 1, bar: 'bar', x: 1 }

The JSON-Schema which is validating everything as expected looks like:

{
  "allOf": [
    {
      "type": "object",
      "properties": {
        "foo": {
          "type": "number"
        }
      },
      "required": [
        "foo"
      ],
    },
    {
      "type": "object",
      "properties": {
        "bar": {
          "type": "string"
        }
      },
      "required": [
        "bar"
      ],
    }
  ],
  "$schema": "http://json-schema.org/draft-07/schema#",
  "unevaluatedProperties": false
}

Note the unevaluatedProperties and the missing additionalProperties.

---

Since we already introduced the and operation in #16990 for the next release, this issue is an regression for:

• gitlab:group:ensureExists
• gitlab:projectAccessToken:create
• gitlab:projectDeployToken:create
• gitlab:projectVariable:create

👍 Expected behavior

scaffolder actions with intersected zod schemas as input should validate correctly

👎 Actual Behavior with Screenshots

see description

👟 Reproduction steps

see description

📃 Provide the context for the Bug.

Zod-Schema with intersected input types

🖥️ Your Environment

backstage 1.13, 1.14-next

👀 Have you spent some time to check if this bug has been raised before?

• I checked and didn't find similar issue

🏢 Have you read the Code of Conduct?

• I have read the Code of Conduct

Are you willing to submit PR?

Yes I am willing to submit a PR!

[freben]

Yeah I see. Indeed, .and doesn't look to be the right thing here. Looking at your ticket, I believe .intersection is the exact same. The way that zod works, it totally makes sense that it'd generate the JSONSchema it does.

Could you look into using merge instead of and? 🙏 That's the semantic operation we want to perform, not multiple strict but distinct schemas applying at the same time.