pytest_collection_finish should be aware of collection errors (session status)

[blueyed]

Currently it is not possible for plugins to now if there is a failure already.

pytest/src/_pytest/main.py

Lines 436 to 447 in 1c2fed3

	def perform_collect(self, args=None, genitems=True):
	hook = self.config.hook
	try:
	items = self._perform_collect(args, genitems)
	self.config.pluginmanager.check_pending()
	hook.pytest_collection_modifyitems(
	session=self, config=self.config, items=items
	)
	finally:
	hook.pytest_collection_finish(session=self)
	self.testscollected = len(items)
	return items

Should be more in line with wrap_session likely, and might be good to have excinfo there additionally to the expected exitcode.

pytest/src/_pytest/main.py

Lines 182 to 224 in 1c2fed3

	def wrap_session(config, doit):
	"""Skeleton command line program"""
	session = Session(config)
	session.exitstatus = ExitCode.OK
	initstate = 0
	try:
	try:
	config._do_configure()
	initstate = 1
	config.hook.pytest_sessionstart(session=session)
	initstate = 2
	session.exitstatus = doit(config, session) or 0
	except UsageError:
	session.exitstatus = ExitCode.USAGE_ERROR
	raise
	except Failed:
	session.exitstatus = ExitCode.TESTS_FAILED
	except (KeyboardInterrupt, exit.Exception):
	excinfo = _pytest._code.ExceptionInfo.from_current()
	exitstatus = ExitCode.INTERRUPTED
	if isinstance(excinfo.value, exit.Exception):
	if excinfo.value.returncode is not None:
	exitstatus = excinfo.value.returncode
	if initstate < 2:
	sys.stderr.write(
	"{}: {}\n".format(excinfo.typename, excinfo.value.msg)
	)
	config.hook.pytest_keyboard_interrupt(excinfo=excinfo)
	session.exitstatus = exitstatus
	except: # noqa
	excinfo = _pytest._code.ExceptionInfo.from_current()
	config.notify_exception(excinfo, config.option)
	session.exitstatus = ExitCode.INTERNAL_ERROR
	if excinfo.errisinstance(SystemExit):
	sys.stderr.write("mainloop: caught unexpected SystemExit!\n")
	finally:
	excinfo = None # Explicitly break reference cycle.
	session.startdir.chdir()
	if initstate >= 2:
	config.hook.pytest_sessionfinish(
	session=session, exitstatus=session.exitstatus
	)

Ref: #2950