Incorrect validation error with scattered nested workflow and pickValue

[bogdang989]

Expected Behavior

Nested workflow output type is string Nested workflow is scattered Main workflow output type is string Main workflow output pickValue is set to first_non_null This should be valid

Actual Behavior

Running cwltool --validate throws a validation error which is incorrect. It seems like the pickValue field is ignored in validation.

Workflow Code

---
class: Workflow
cwlVersion: v1.2
id: example
label: main_out_str
"$namespaces":
  sbg: https://sevenbridges.com
inputs:
- id: input
  type: File[]?
  sbg:x: -233.0658416748047
  sbg:y: -266.9961853027344
outputs:
- id: output
  outputSource:
  - nested_wf_out_str_array/output
  type: string?
  sbg:x: 381.93414306640625
  sbg:y: -214.9961700439453
  pickValue: first_non_null
steps:
- id: nested_wf_out_str_array
  in:
  - id: input
    source: input
  out:
  - id: output
  run:
    class: Workflow
    cwlVersion: v1.2
    id: bogdang/cwl1-2/nested-wf-out-str-array/3
    label: nested_wf_out_str_array
    "$namespaces":
      sbg: https://sevenbridges.com
    inputs:
    - id: input
      type: File?
      sbg:x: -202.0658416748047
      sbg:y: -237.9961700439453
    outputs:
    - id: output
      outputSource:
      - out_str/output
      type: string?
      sbg:x: 346.93414306640625
      sbg:y: -170.9961700439453
    steps:
    - id: out_str
      in:
      - id: input
        source: input
      out:
      - id: output
      run:
        class: CommandLineTool
        cwlVersion: v1.2
        "$namespaces":
          sbg: https://sevenbridges.com
        id: bogdang/cwl1-2/out-str/1
        baseCommand: []
        inputs:
        - id: input
          type: File?
          inputBinding:
            shellQuote: false
            position: 0
        outputs:
        - id: output
          type: string?
        label: out_str
        requirements:
        - class: ShellCommandRequirement
      label: out_str
    requirements:
    - class: InlineJavascriptRequirement
    - class: StepInputExpressionRequirement
  label: nested_wf_out_str_array
  scatter:
  - input
requirements:
- class: SubworkflowFeatureRequirement
- class: ScatterFeatureRequirement
- class: InlineJavascriptRequirement
- class: StepInputExpressionRequirement

Full Traceback

ERROR Tool definition failed validation:

a.cwl:39:17: Source 'output' of type {"type": "array", "items": ["null", "string"]} is incompatible
a.cwl:23:13:   with sink 'output' of type ["null", "string"]
a.cwl:18:9:     pickValue is: first_non_null
Traceback (most recent call last):
  File "/Users/bogdangavrilovic/opt/miniconda3/lib/python3.8/site-packages/cwltool/main.py", line 1072, in main
    tool = make_tool(uri, loadingContext)
  File "/Users/bogdangavrilovic/opt/miniconda3/lib/python3.8/site-packages/cwltool/load_tool.py", line 460, in make_tool
    tool = loadingContext.construct_tool_object(processobj, loadingContext)
  File "/Users/bogdangavrilovic/opt/miniconda3/lib/python3.8/site-packages/cwltool/workflow.py", line 51, in default_make_tool
    return Workflow(toolpath_object, loadingContext)
  File "/Users/bogdangavrilovic/opt/miniconda3/lib/python3.8/site-packages/cwltool/workflow.py", line 135, in __init__
    static_checker(
  File "/Users/bogdangavrilovic/opt/miniconda3/lib/python3.8/site-packages/cwltool/checker.py", line 331, in static_checker
    raise ValidationException(all_exception_msg)
schema_salad.exceptions.ValidationException:
a.cwl:39:17: Source 'output' of type {"type": "array", "items": ["null", "string"]} is incompatible
a.cwl:23:13:   with sink 'output' of type ["null", "string"]
a.cwl:18:9:     pickValue is: first_non_null

Your Environment

• cwltool version: 3.1.20210921111717