actionlint detect warning when using inputs type conversion with fromJSON

[guitarrapc]

Summary

actionlint warn when trying to use JSON data type conversion pattern and it's too strict, or other word too smart then what agent do.

Warning message

$ actionlint

.github\workflows\actionlint_issue.yaml:15:30: 1st argument of function call is not assignable. "bool" cannot be assigned to "string". called function type is "fromJSON(string) -> any" [expression]
   |
15 |       is-valid: ${{ fromJson(github.event.inputs.is-valid) }}

Detail

When reusable workflow have inputs type boolean and want pass boolean from workflow_dispatch, JSON data type convert with fromJSON expression is officially introduced pattern.

see: https://docs.github.com/en/actions/learn-github-actions/expressions#example-returning-a-json-data-type

Without fromJSON, github.event.inputs.foo treat as string and cannot pass to workflow_call.
However actionlint warn this and seems guessing parameter as boolean is too smart then what agent do.

Reproduce code

1. Prepare 2 workflows actionlint.yaml and _reusable.yaml

name: actionlint issue

on:
  workflow_dispatch:
    inputs:
      is-valid:
        required: true
        description: "is-valid: true or false"
        type: boolean

jobs:
  issue:
    uses: ./.github/workflows/_reusable.yaml
    with:
      is-valid: ${{ fromJson(github.event.inputs.is-valid) }}

name: _reusable

on:
  workflow_call:
    inputs:
      is-valid:
        required: true
        description: username to show
        type: boolean

jobs:
  reusable_workflow_job:
    runs-on: ubuntu-latest
    steps:
      - name: called is-valid
        run: echo "called is-valid. ${{ inputs.is-valid }}"

2. run actionlint.

Workaround

Pass string to fromJSON not boolean, via format('{0}', github.event.inputs.foo).

name: actionlint issue

<reducted>

jobs:
  issue:
    uses: ./.github/workflows/_reusable.yaml
    with:
      is-valid: ${{ fromJson(format('{0}', github.event.inputs.is-valid)) }}

[rhysd]

Thank you for the detailed report with reproduction. This looks a bug of actionlint.

[rhysd]

Type of the input is specified as boolean at on.workflow_dispatch.inputs.<name>.type but it is only used for validation. Type of inputs.<name> is always string. But actionlint statically types inputs.<name> is boolean looking at the specification.

I'm not sure this is an expected behavior because the official document says:

inputs.<name> | string or number or boolean | Each input value passed from an external workflow.

https://docs.github.com/en/actions/learn-github-actions/contexts#inputs-context

From this document, correct type of the inputs.is-valid sounds boolean.

[rhysd]

I made a question at https://github.com/orgs/community/discussions/29796

[rhysd]

@guitarrapc By the way, inputs context instead of github.event.inputs solves this issue. It is typed correctly as boolean. If you still have this issue, please try the following:

is-valid: ${{ inputs.is-valid }}

[johnfoconnor]

Im running into this issue with the following code

Error: .github/workflows/populate_caches.yaml:38:16: input "timeout" is typed as number by reusable workflow "./.github/workflows/unity-tests.yaml". string value cannot be assigned [expression]

    strategy:
      matrix:
        timeout:
          # hack to allow a configurable number timeout as input. see
          # https://docs.github.com/en/actions/learn-github-actions/expressions#example-returning-a-json-data-type
          - ${{ fromJSON(inputs.timeout || '40') }}
    with:
      timeout: ${{ matrix.timeout }}

If a fix is not possible, I would appreciate a way to annotate the code to ignore the linter for this line