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.
The unique identifier for this object.
A short, human-readable label of this object.
The method to use to merge multiple inbound links into a single array. If not specified, the default method is "merge_nested".
Only valid when type: File or is an array of items: File. Read up to the first 64 KiB of text from the file and place it in the "contents" field of the file object for use by expressions.
Only valid when type: Directory or is an array of items: Directory. Specify the desired behavior for loading the listing field of a Directory object for use by expressions. The order of precedence for loadListing is: 1. loadListing on an individual parameter 2. Inherited from LoadListingRequirement 3. By default: no_listing
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. If valueFrom is a constant string value, use this as the value for this input parameter. If valueFrom is a parameter reference or expression, it must be evaluated to yield the actual value to be assiged to the input field. The self value in the parameter reference or expression must be 1. null if there is no source field 2. the value of the parameter(s) specified in the source field when this workflow input parameter **is not** specified in this workflow step's scatter field. 3. an element of the parameter specified in the source field when this workflow input parameter **is** specified in this workflow step's scatter field. The value of inputs in the parameter reference or expression must be the input object to the workflow step after assigning the source values, applying default, and then scattering. The order of evaluating valueFrom among step input parameters is undefined and the result of evaluating valueFrom on a parameter must not be visible to evaluation of valueFrom on other parameters.
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 process specified by the run field. Only input parameters declared by the target process will be passed through at runtime to the process though additonal parameters may be specified (for use within valueFrom expressions for instance) - unconnected or unused parameters do not represent an error condition. ## 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.