Ensure hashCode and equivalence tests are order independent.

Signed-off-by: Rob Syme <[email protected]>

modules/nextflow/src/main/groovy/nextflow/util/ArrayBag.groovy

@@ -65,14 +65,35 @@ class ArrayBag<E> implements Bag<E>, List<E>, KryoSerializable {
 
    @Override
    int hashCode() {
-       target.hashCode()
+       int hash = 0
+       target.each { element ->
+           hash ^= (element != null ? element.hashCode() : 0)
+       }
+       return hash
    }
 
    @Override
    boolean equals(Object o) {
-       target.equals(o)
+       if (this.is(o)) return true
+       if (!(o instanceof ArrayBag)) return false
+
+       ArrayBag other = (ArrayBag) o
+       def thisFrequencyMap = createFrequencyMap(this.target)
+       def otherFrequencyMap = createFrequencyMap(other.target)
+
+       return thisFrequencyMap == otherFrequencyMap
    }
 
+    private static Map<Object, Integer> createFrequencyMap(List list) {
+        Map<Object, Integer> frequencyMap = [:]
+        list.each { element ->
+            if (element != null) {
+                frequencyMap[element] = frequencyMap.getOrDefault(element, 0) + 1
+            }
+        }
+        return frequencyMap
+    }
+
 //    E getAt( int index )  {
 //        target.get(index)
 //    }

modules/nextflow/src/test/groovy/nextflow/extension/JoinOpTest.groovy

@@ -224,6 +224,20 @@ class JoinOpTest extends Specification {
         !result.isEmpty()
     }
 
+    def 'should differentiate nonidentical ArrayBags join key' () {
+        given:
+        def key1 = new ArrayBag(["key", "key", "quay"])
+        def key2 = new ArrayBag(["quay", "quay", "key"])
+        def ch1 = Channel.of([key1, "foo"])
+        def ch2 = Channel.of([key2, "bar"])
+
+        when:
+        def op = new JoinOp(ch1 as DataflowReadChannel, ch2 as DataflowReadChannel)
+        List result = op.apply().toList().getVal()
+
+        then:
+        result.isEmpty()
+    }
 
     def 'should not fail on mismatches' () {
         given: