# 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, 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, 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, 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, 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"
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