The default value for this parameter to use if either there is no source field, or the value produced by the source is null. The default must be applied prior to scattering or evaluating valueFrom.
A unique identifier for this workflow input parameter.
The method to use to merge multiple inbound links into a single array. If not specified, the default method is "merge_nested".
Specifies one or more workflow parameters that will provide input to the underlying step parameter.
To use valueFrom, StepInputExpressionRequirement must be specified in the workflow or workflow step requirements.
The input of a workflow step connects an upstream parameter (from the workflow inputs, or the outputs of other workflows steps) with the input parameters of the underlying step.
Input object
A WorkflowStepInput object must contain an id field in the form #fieldname or #prefix/fieldname. When the id field contains a slash / the field name consists of the characters following the final slash (the prefix portion may contain one or more slashes to indicate scope). This defines a field of the workflow step input object with the value of the source parameter(s).
Merging
To merge multiple inbound data links, MultipleInputFeatureRequirement must be specified in the workflow or workflow step requirements.
If the sink parameter is an array, or named in a [workflow scatter](#WorkflowStep) operation, there may be multiple inbound data links listed in the source field. The values from the input links are merged depending on the method specified in the linkMerge field. If not specified, the default method is "merge_nested".
* **merge_nested**
The input must be an array consisting of exactly one entry for each input link. If "merge_nested" is specified with a single link, the value from the link must be wrapped in a single-item list.
* **merge_flattened**
1. The source and sink parameters must be compatible types, or the source type must be compatible with single element from the "items" type of the destination array parameter. 2. Source parameters which are arrays are concatenated. Source parameters which are single element types are appended as single elements.