Hi guys, My name is Isaiah, I'm currently trying to implement invokedynamic for my Python 3 implementation. Everything went quite well until I encountered a `ClassCastException` which I don't know how to fix.
Here is my theory: there are two method calls that has the same arity, with signatures of: `(LPyObject;LThreadState;[LPyObject;LString;)LPyObject` and `(LPyObject;LThreadState;LPyObject;LPyObject)LPyObject` The former is for methods that take vararg and keyword arguments, the later is for methods that take two arguments. The stacktrace is as following: java.lang.ClassCastException: Cannot cast [Ljava.lang.String; to org.python.core.PyObject at java.base/java.lang.Class.cast(Class.java:3578) at contextlib_jython_36.__init__$12(contextlib:67) at org.python.core.Py.runCode(Py.java:1663) at org.python.core.PyTableCode.call(PyTableCode.java:404) at org.python.core.PyTableCode.call(PyTableCode.java:382) at org.python.core.PyFunction.__call__(PyFunction.java:442) at org.python.core.PyMethod.instancemethod___call__(PyMethod.java:237) at org.python.core.PyMethod.__call__(PyMethod.java:228) at org.python.core.PyMethod.__call__(PyMethod.java:223) at org.python.core.Deriveds.dispatch__init__(Deriveds.java:19) at org.python.core.PyObjectDerived.dispatch__init__(PyObjectDerived.java:940) at org.python.core.PyType.type___call__(PyType.java:1675) at org.python.core.PyType$type___call___exposer.__call__(Unknown Source) at org.python.core.PyTypeDerived.__call__(PyTypeDerived.java:831) at org.python.core.PyObject.__call__(PyObject.java:506) at org.python.core.PyObject.__call__(PyObject.java:510) at contextlib_jython_36.helper$17(contextlib:159) The GuardedInvocation returned from the linker is like: `return new GuardedInvocation(mh, null, new SwitchPoint[0], ClassCastException.class);` It seems to be able to catch the class cast exception for the receiver but not for arguments. I create a similar call path and the function works fine, so I thought the cause could be the callsite is not invalidated. My question is: Is my guess correct? if so why does it reuse the callsite when the signatures are different? and how to create a guard for such case? The source code can be found here: https://bitbucket.org/jylang/jylang/src/e0c64d17b21db7784c75892424cae09f9faa07d3/src/org/python/core/PyFunction.java?at=indy&fileviewer=file-view-default#PyFunction.java-513 Thanks in advance, Isaiah Peng