Merge pull request #242 from common-workflow-language/scatter-inputs

Scatter inputs valueFrom use post-scatter inputs

Author: mr-c

draft-4/Workflow.yml

@@ -255,10 +255,12 @@ $graph:
         the value of the parameter(s) specified in the `source` field, or
         null if there is no `source` field.
 
-        The value of `inputs` in the parameter reference or expression is the
-        input object to the workflow step after assigning the `source` values,
-        but before evaluating any step with `valueFrom`.  The order of
-        evaluating `valueFrom` among step input parameters is undefined.
+        The value of `inputs` in the parameter reference or expression must be
+        the input object to the workflow step after assigning the `source`
+        values 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.
 
 
 - type: record

draft-4/conformance_test_draft-4.yaml

@@ -691,6 +691,12 @@
   tool: "draft-4/scatter-valuefrom-wf4.cwl#main"
   doc: Test workflow scatter with two scatter parameters and dotproduct join method and valueFrom on step input
 
+- job: draft-4/scatter-valuefrom-job1.json
+  output:
+    out: ["foo one one", "foo two two", "foo three three", "foo four four"]
+  tool: draft-4/scatter-valuefrom-wf5.cwl
+  doc: Test workflow scatter with single scatter parameter and valueFrom on step input
+
 - job: draft-4/conflict-job.json
   output: {
     "fileout": {

draft-4/draft-4/scatter-valuefrom-wf5.cwl

@@ -0,0 +1,58 @@
+#!/usr/bin/env cwl-runner
+cwlVersion: cwl:draft-4.dev3
+class: Workflow
+inputs:
+  inp:
+    type:
+      type: array
+      items:
+        type: record
+        name: instr
+        fields:
+          - name: instr
+            type: string
+outputs:
+  out:
+    type:
+      type: array
+      items: string
+    outputSource: step1/echo_out
+
+requirements:
+  - class: ScatterFeatureRequirement
+  - class: StepInputExpressionRequirement
+
+steps:
+  step1:
+    in:
+      echo_in:
+        source: inp
+        valueFrom: $(self.instr)
+      first:
+        source: inp
+        valueFrom: $(inputs.echo_in.instr)
+    out: [echo_out]
+    scatter: echo_in
+    run:
+      class: CommandLineTool
+      inputs:
+        first:
+          type: string
+          inputBinding:
+            position: 1
+        echo_in:
+          type: string
+          inputBinding:
+            position: 2
+      outputs:
+        echo_out:
+          type: string
+          outputBinding:
+            glob: "step1_out"
+            loadContents: true
+            outputEval: $(self[0].contents)
+      baseCommand: "echo"
+      arguments:
+        - "-n"
+        - "foo"
+      stdout: "step1_out"