# errorSemantics.py # Test the Python error handling semantics. Specifically: # # * When a Python COM object is called via IDispatch, the nominated # scode is placed in the exception tuple, and the HRESULT is # DISP_E_EXCEPTION # * When the same interface is called via IWhatever, the # nominated scode is returned directly (with the scode also # reflected in the exception tuple) # * In all cases, the description etc end up in the exception tuple # * "Normal" Python exceptions resolve to an E_FAIL "internal error" import pythoncom from win32com.server.exception import COMException from win32com.server.util import wrap from win32com.client import Dispatch import winerror from win32com.test.util import CaptureWriter class error(Exception): def __init__(self, msg, com_exception=None): Exception.__init__(self, msg, str(com_exception)) # Our COM server. class TestServer: _public_methods_ = [ 'Clone', 'Commit', 'LockRegion', 'Read'] _com_interfaces_ = [ pythoncom.IID_IStream ] def Clone(self): raise COMException("Not today", scode=winerror.E_UNEXPECTED) def Commit(self, flags): raise Exception("foo") def test(): # Call via a native interface. com_server = wrap(TestServer(), pythoncom.IID_IStream) try: com_server.Clone() raise error("Expecting this call to fail!") except pythoncom.com_error as com_exc: if com_exc.hresult != winerror.E_UNEXPECTED: raise error("Calling the object natively did not yield the correct scode", com_exc) exc = com_exc.excepinfo if not exc or exc[-1] != winerror.E_UNEXPECTED: raise error("The scode element of the exception tuple did not yield the correct scode", com_exc) if exc[2] != "Not today": raise error("The description in the exception tuple did not yield the correct string", com_exc) cap = CaptureWriter() try: cap.capture() try: com_server.Commit(0) finally: cap.release() raise error("Expecting this call to fail!") except pythoncom.com_error as com_exc: if com_exc.hresult != winerror.E_FAIL: raise error("The hresult was not E_FAIL for an internal error", com_exc) if com_exc.excepinfo[1] != "Python COM Server Internal Error": raise error("The description in the exception tuple did not yield the correct string", com_exc) # Check we saw a traceback in stderr if cap.get_captured().find("Traceback")<0: raise error("Could not find a traceback in stderr: %r" % (cap.get_captured(),)) # Now do it all again, but using IDispatch com_server = Dispatch(wrap(TestServer())) try: com_server.Clone() raise error("Expecting this call to fail!") except pythoncom.com_error as com_exc: if com_exc.hresult != winerror.DISP_E_EXCEPTION: raise error("Calling the object via IDispatch did not yield the correct scode", com_exc) exc = com_exc.excepinfo if not exc or exc[-1] != winerror.E_UNEXPECTED: raise error("The scode element of the exception tuple did not yield the correct scode", com_exc) if exc[2] != "Not today": raise error("The description in the exception tuple did not yield the correct string", com_exc) cap.clear() try: cap.capture() try: com_server.Commit(0) finally: cap.release() raise error("Expecting this call to fail!") except pythoncom.com_error as com_exc: if com_exc.hresult != winerror.DISP_E_EXCEPTION: raise error("Calling the object via IDispatch did not yield the correct scode", com_exc) exc = com_exc.excepinfo if not exc or exc[-1] != winerror.E_FAIL: raise error("The scode element of the exception tuple did not yield the correct scode", com_exc) if exc[1] != "Python COM Server Internal Error": raise error("The description in the exception tuple did not yield the correct string", com_exc) # Check we saw a traceback in stderr if cap.get_captured().find("Traceback")<0: raise error("Could not find a traceback in stderr: %r" % (cap.get_captured(),)) try: import logging except ImportError: logging = None if logging is not None: import win32com class TestLogHandler(logging.Handler): def __init__(self): self.num_emits = 0 logging.Handler.__init__(self) def emit(self, record): self.num_emits += 1 return print("--- record start") print(self.format(record)) print("--- record end") def testLogger(): assert not hasattr(win32com, "logger") handler = TestLogHandler() formatter = logging.Formatter('%(message)s') handler.setFormatter(formatter) log = logging.getLogger("win32com_test") log.addHandler(handler) win32com.logger = log # Now throw some exceptions! # Native interfaces com_server = wrap(TestServer(), pythoncom.IID_IStream) try: com_server.Commit(0) raise RuntimeError("should have failed") except pythoncom.error: pass assert handler.num_emits == 1, handler.num_emits handler.num_emits = 0 # reset com_server = Dispatch(wrap(TestServer())) try: com_server.Commit(0) raise RuntimeError("should have failed") except pythoncom.error: pass assert handler.num_emits == 1, handler.num_emits if __name__=='__main__': test() if logging is not None: testLogger() from .util import CheckClean CheckClean() print("error semantic tests worked")