Common Mistakes

Multi Line Expressions in if

Wrong

if: |
  ${{
    success()
    && needs.test.result == 'success'
  }}

this ends up like "${{ format('{0}\n', success() && needs.test.result == 'success') }}" and is equivalent to "always()"

Correct

if: |-
  ${{
    success()
    && needs.test.result == 'success'
  }}

if: |
  success()
  && needs.test.result == 'success'

if: |-
  success()
  && needs.test.result == 'success'

Multi Line Expressions with non string type

Wrong

matrix: |
  ${{
    fromjson('{
        "Hello": ["World"]
    }')
  }}

this ends up like "${{ format('{0}\n', fromjson('{\n "Hello": ["World"]\n }')) }}" and is equivalent to "Object\n"

Correct

matrix: |-
  ${{
    fromjson('{
        "Hello": ["World"]
    }')
  }}

Jobs are skipped even if dependent jobs succeed

By default all job if conditons not using any function of success(), always(), cancelled() or failure(), are rewritten as success() && (<old-condition>)

Wrong

if: "true"
needs:
- dependency1
- dependency2

this will be rewritten to

if: "success() && true"
needs:
- dependency1
- dependency2

and is skipped once any transitive dependency has been skipped, failed or the workflow has been cancelled.

Correct

parameters of success not supported in act

if: "success('dependency1', 'dependency2`) && true"
needs:
- dependency1
- dependency2

Otherwise use the far more verbose syntax

if: "!cancelled() && needs.dependency1.result == 'success' && needs.dependency2.result == 'success' && true"
needs:
- dependency1
- dependency2

Do not use always(), if you don't want to risk not beeing able to cancel the job while force cancel api might be a solution outside of a GitHub Actions Outage.

Passing parameter as boolean in Reusable Workflows

Wrong for push

on:
  push:
  workflow_dispatch:
    inputs:
      BOOLEAN:
        type: boolean
jobs:
  test:
    uses: ./.github/workflows/workflow.yml
    with:
      BOOLEAN: ${{ inputs.BOOLEAN }}

Correct

on:
  push:
  workflow_dispatch:
    inputs:
      BOOLEAN:
        type: boolean
jobs:
  test:
    uses: ./.github/workflows/workflow.yml
    with:
      BOOLEAN: ${{ inputs.BOOLEAN || false }}

Passing string as number in Reusable Workflows

Wrong

on:
  push:
  workflow_dispatch:
    inputs:
      NUMBER: {}
jobs:
  test:
    uses: ./.github/workflows/workflow.yml
    with:
      NUMBER: ${{ inputs.NUMBER }}

Wrong for push

on:
  push:
  workflow_dispatch:
    inputs:
      NUMBER: {}
jobs:
  test:
    uses: ./.github/workflows/workflow.yml
    with:
      NUMBER: ${{ fromJson(inputs.NUMBER) }}

Correct

on:
  push:
  workflow_dispatch:
    inputs:
      NUMBER: {}
jobs:
  test:
    uses: ./.github/workflows/workflow.yml
    with:
      NUMBER: ${{ fromJson(inputs.NUMBER || '0') }}

on:
  push:
  workflow_dispatch:
    inputs:
      NUMBER: {}
jobs:
  test:
    uses: ./.github/workflows/workflow.yml
    with:
      NUMBER: ${{ inputs.NUMBER && fromJson(inputs.NUMBER) || 0 }}

Accessing index by actions context in if

Wrong

if: steps[${{ steps.token.outputs.y }}].outputs.test == 'ok'

This ends up as ${{ success() && format('steps[{0}].outputs.test == ''ok''', steps.token.outputs.y) }} and is similar to ${{ success() }} or ${{ success() && 'Non Empty String' }}.

Correct

if: steps[steps.token.outputs.y].outputs.test == 'ok'

Comparing Reusable Workflow booleans

Wrong

on:
  workflow_call:
    inputs:
      b:
        type: boolean # This is important for this to not work
jobs:
  test:
    if: ${{ inputs.b == 'true' }}

Correct

on:
  workflow_call:
    inputs:
      b:
        type: boolean
jobs:
  test:
    if: ${{ inputs.b == true }}

on:
  workflow_call:
    inputs:
      b:
        type: boolean
jobs:
  test:
    if: ${{ inputs.b }}

on:
  workflow_call:
    inputs:
      b:
        type: boolean
jobs:
  test:
    if: ${{ format('{0}', inputs.b) == 'true' }}

Types in composite actions don't exist

All inputs are strings, for whatever reason this type field is not producing an error and is allowed as additional property

Wrong

inputs:
  B:
    type: boolean # No such field defined in spec
    default: false
runs:
  using: composite
  steps:
  - run: echo test
    if: inputs.B

inputs:
  B:
    type: boolean # No such field defined in spec
    default: false
runs:
  using: composite
  steps:
  - run: echo test
    if: inputs.B == true

Correct

inputs:
  B:
    default: false
runs:
  using: composite
  steps:
  - run: echo test
    if: inputs.B == 'true'