fix(python): support variadic arguments (#513)

* Properly handle variadic args

* update compliance test to call VariadicMethod.

* Remove commented line.

* Cleaning up code

* Update the expected output

* Further simplification of code

Author: garnaat

packages/jsii-pacmak/lib/targets/python.ts

@@ -467,9 +467,10 @@ abstract class BaseMethod implements PythonBase {
             jsiiMethodParams.push(`"${this.jsName}"`);
         }
 
+        // If the last arg is variadic, expand the tuple
         const paramNames: string[] = [];
         for (const param of this.parameters) {
-            paramNames.push(toPythonParameterName(param.name));
+            paramNames.push((param.variadic ? '*' : '') + toPythonParameterName(param.name));
         }
 
         code.line(`${methodPrefix}jsii.${this.jsiiMethod}(${jsiiMethodParams.join(", ")}, [${paramNames.join(", ")}])`);

packages/jsii-pacmak/test/expected.jsii-calc/python/src/jsii_calc/__init__.py

@@ -678,7 +678,7 @@ def optional_and_variadic(self, optional: typing.Optional[str]=None, *things: st
             optional: -
             things: -
         """
-        return jsii.invoke(self, "optionalAndVariadic", [optional, things])
+        return jsii.invoke(self, "optionalAndVariadic", [optional, *things])
 
 
 class EraseUndefinedHashValues(metaclass=jsii.JSIIMeta, jsii_type="jsii-calc.EraseUndefinedHashValues"):
@@ -2994,7 +2994,7 @@ def __init__(self, *prefix: jsii.Number) -> None:
         Arguments:
             prefix: a prefix that will be use for all values returned by ``#asArray``.
         """
-        jsii.create(VariadicMethod, self, [prefix])
+        jsii.create(VariadicMethod, self, [*prefix])
 
     @jsii.member(jsii_name="asArray")
     def as_array(self, first: jsii.Number, *others: jsii.Number) -> typing.List[jsii.Number]:
@@ -3003,7 +3003,7 @@ def as_array(self, first: jsii.Number, *others: jsii.Number) -> typing.List[jsii
             first: the first element of the array to be returned (after the ``prefix`` provided at construction time).
             others: other elements to be included in the array.
         """
-        return jsii.invoke(self, "asArray", [first, others])
+        return jsii.invoke(self, "asArray", [first, *others])
 
 
 class VirtualMethodPlayground(metaclass=jsii.JSIIMeta, jsii_type="jsii-calc.VirtualMethodPlayground"):

packages/jsii-python-runtime/tests/test_compliance.py

@@ -42,6 +42,7 @@
     UsesInterfaceWithProperties,
     composition,
     EraseUndefinedHashValues,
+    VariadicMethod,
 )
 from scope.jsii_calc_lib import IFriendly, EnumFromScopedModule, Number
 
@@ -895,3 +896,8 @@ def consume_partially_initialized_this(self, obj, dt, en):
     reflector = PartiallyInitializedThisConsumerImpl()
     obj = ConstructorPassesThisOut(reflector)
     assert obj is not None
+
+
+def test_variadicMethodCanBeInvoked():
+    variadic = VariadicMethod(1)
+    assert variadic.as_array(3, 4, 5, 6) == [1, 3, 4, 5, 6]