Native translation of copyProperties (#281)

Signed-off-by: Dwitry dwitry@users.noreply.github.com

Author: dwitry

testware/integration-tests/src/test/java/org/opencypher/gremlin/queries/SetTest.java

@@ -294,8 +294,7 @@ public void copyPropertiesRelationshipToNode() {
     public void copyPropertiesFromNull() {
         submitAndGet("CREATE (:TO {prop1: 'x', prop3: 'y'})");
 
-        assertThatThrownBy(() -> submitAndGet("OPTIONAL MATCH (x:NOT_EXISTING) WITH x MATCH (to:TO) SET to=x RETURN to"))
-            .hasMessageContaining("Expected   cypher.null to be Element");
+        assertThatThrownBy(() -> submitAndGet("OPTIONAL MATCH (x:NOT_EXISTING) WITH x MATCH (to:TO) SET to=x RETURN to"));
     }
 
     @Test

tinkerpop/cypher-gremlin-extensions/README.md

@@ -96,14 +96,6 @@ In Gremlin different steps are required for each type:
 
 If type information is unknown (or on string concatenation) - custom function is used. If Gremlin Extensions for Cypher Support are not installed, translation falls back to number operator.
 
-### Copying Properties from node to node
-
-```cypher
-MATCH (n:FROM)-[r]->(m:TO) SET m=n RETURN m
-```
-
-Gremlin [AddProperty step](http://tinkerpop.apache.org/docs/current/reference/#addproperty-step) only allows setting a single value, where the property name is constant. It is unknown how to copy all properties from one element to another.
-
 ## Translation Workarounds
 
 ### Null handling

tinkerpop/cypher-gremlin-extensions/src/main/java/org/opencypher/gremlin/traversal/CustomFunctions.java

@@ -464,20 +464,6 @@ public static Function<Traverser, Object> cypherReplace() {
             String.class, String.class, String.class);
     }
 
-    public static Function<Traverser, Object> cypherCopyProperties() {
-        return traverser -> {
-            List args = cast(traverser.get(), List.class);
-            if (args.get(0) == Tokens.NULL) {
-                return Tokens.NULL;
-            }
-
-            Element to = cast(args.get(0), Element.class);
-            Element from = cast(args.get(1), Element.class);
-            from.properties().forEachRemaining(prop -> to.property(prop.key(), prop.value()));
-            return to;
-        };
-    }
-
     public static Function<Traverser, Object> cypherException() {
         return traverser -> {
             String message = CypherExceptions.messageByName(traverser.get());

translation/src/main/java/org/opencypher/gremlin/translation/GremlinSteps.java

@@ -200,6 +200,8 @@ GremlinSteps<T, P> choose(GremlinSteps<T, P> traversalPredicate,
 
     GremlinSteps<T, P> property(String key, GremlinSteps<T, P> traversal);
 
+    GremlinSteps<T, P> property(GremlinSteps<T, P> keyTraversal, GremlinSteps<T, P> valueTraversal);
+
     GremlinSteps<T, P> property(Cardinality cardinality, String key, GremlinSteps<T, P> traversal);
 
     GremlinSteps<T, P> project(String... keys);

translation/src/main/java/org/opencypher/gremlin/translation/bytecode/BytecodeGremlinSteps.java

@@ -484,6 +484,12 @@ public GremlinSteps<Bytecode, P> property(String key, GremlinSteps<Bytecode, P>
         return this;
     }
 
+    @Override
+    public GremlinSteps<Bytecode, P> property(GremlinSteps<Bytecode, P> keyTraversal, GremlinSteps<Bytecode, P> valueTraversal) {
+        bytecode.addStep(Symbols.property, keyTraversal.current(), valueTraversal.current());
+        return this;
+    }
+
     @Override
     public GremlinSteps<Bytecode, P> property(Cardinality cardinality, String key, GremlinSteps<Bytecode, P> traversal) {
         bytecode.addStep(Symbols.property, cardinality, key, traversal.current());

translation/src/main/java/org/opencypher/gremlin/translation/groovy/GroovyGremlinSteps.java

@@ -493,6 +493,12 @@ public GremlinSteps<String, GroovyPredicate> property(String key, GremlinSteps<S
         return this;
     }
 
+    @Override
+    public GremlinSteps<String, GroovyPredicate> property(GremlinSteps<String, GroovyPredicate> keyTraversal, GremlinSteps<String, GroovyPredicate> valueTraversal) {
+        g.append(chain("property", traversal(keyTraversal), traversal(valueTraversal)));
+        return this;
+    }
+
     @Override
     public GremlinSteps<String, GroovyPredicate> property(Cardinality cardinality, String key, GremlinSteps<String, GroovyPredicate> traversal) {
         g.append(chain("property", cardinality, key, traversal(traversal)));

translation/src/main/java/org/opencypher/gremlin/translation/traversal/TraversalGremlinSteps.java

@@ -520,6 +520,12 @@ public GremlinSteps<GraphTraversal, P> property(String key, GremlinSteps<GraphTr
         return property(key, traversal.current());
     }
 
+    @Override
+    public GremlinSteps<GraphTraversal, P> property(GremlinSteps<GraphTraversal, P> keyTraversal, GremlinSteps<GraphTraversal, P> valueTraversal) {
+        g.property(keyTraversal.current(), valueTraversal.current());
+        return this;
+    }
+
     @Override
     public GremlinSteps<GraphTraversal, P> property(Cardinality cardinality, String key, GremlinSteps<GraphTraversal, P> traversal) {
         g.property(cardinality, key, traversal.current());

translation/src/main/java/org/opencypher/gremlin/traversal/CustomFunction.java

@@ -177,13 +177,6 @@ public static CustomFunction cypherReplace() {
         );
     }
 
-    public static CustomFunction cypherCopyProperties() {
-        return new CustomFunction(
-            "cypherCopyProperties",
-            CustomFunctions.cypherCopyProperties()
-        );
-    }
-
     @Override
     public boolean equals(Object o) {
         if (this == o) return true;

translation/src/main/scala/org/opencypher/gremlin/translation/ir/TranslationWriter.scala

@@ -222,6 +222,8 @@ sealed class TranslationWriter[T, P] private (translator: Translator[T, P], para
           g.property(cardinality, key, writeValue(value))
         case PropertyT(key, traversal) =>
           g.property(key, writeLocalSteps(traversal))
+        case PropertyT2(keyTraversal, valueTraversal) =>
+          g.property(writeLocalSteps(keyTraversal), writeLocalSteps(valueTraversal))
         case PropertyTC(cardinality, key, traversal) =>
           g.property(cardinality, key, writeLocalSteps(traversal))
         case Project(keys @ _*) =>

translation/src/main/scala/org/opencypher/gremlin/translation/ir/builder/IRGremlinSteps.scala

@@ -422,6 +422,14 @@ class IRGremlinSteps extends GremlinSteps[Seq[GremlinStep], GremlinPredicate] {
     this
   }
 
+  override def property(
+      keyTraversal: GremlinSteps[Seq[GremlinStep], GremlinPredicate],
+      valueTraversal: GremlinSteps[Seq[GremlinStep], GremlinPredicate])
+    : GremlinSteps[Seq[GremlinStep], GremlinPredicate] = {
+    buf += PropertyT2(keyTraversal.current(), valueTraversal.current())
+    this
+  }
+
   override def property(
       cardinality: Cardinality,
       key: String,