Flow's untyped input defaults can lead to runtime errors

[yuri1969]

Describe the issue

TL;DR flow's input defaults should be correctly typed.

---

Currently the flow's input defaults field is not typed - it is a simple Object. This can lead to unexpected runtime errors in situations when a wrongly typed default is effectively applied and a validator is defined.

For example, a validated STRING input with defaults being an integer fails since the validator can not be applied on an integer:

id: badDefaults
namespace: io.kestra.tests

inputs:
  - id: intDefaultsInStrInput
    type: STRING
    validator: '\d+'
    defaults: 100
    required: false

tasks:
  - id: date
    type: io.kestra.plugin.core.debug.Return
    format: "{{taskrun.startDate}}"

Execute the flow above using the API and omit the flow input completely - the execution fails on validation.

---

The same behavior can be demonstrated by the following unit test: mismatchedDefaults.patch

---

It feels like this issue should be easily solved by switching the Inputs defaults attribute type from Object to the generic type T - Input.java L81. It enables JSON Schema generation for the defaults.

However, it breaks at least the TIME input a bit - JSON Schema's time requires timezone. Also the value itself is not validated.

Environment

• Kestra Version: v0.20-SNAPSHOT
• Operating System (OS/Docker/Kubernetes):
• Java Version (if you don't run kestra in Docker): 21 Temurin

[Malaydewangan09]

Hey @loicmathieu
Can I pick this up?
Thanks!

[loicmathieu]

@Malaydewangan09 yes, I assigned you to the issue.

[Malaydewangan09]

@loicmathieu Thanks!