WIP play around with config initialization

While investigating a recent node id bug (#445) I decided to play
with config initialization around the idea of initializing the config
on the remote *exactly* we initialize the config object on pytest.main()

One thing that immediately broke all tests was inprocess pytester runs,
but other than that just a few tests failed which I find encouraging.

While this patch is in no way even remotely ready, I would like to get
opinions if the overall idea of initializing the config object
like this is sound.

Author: nicoddemus

src/xdist/remote.py

@@ -15,6 +15,8 @@
 import pytest
 from execnet.gateway_base import dumps, DumpError
 
+from _pytest.config import _prepareconfig
+
 
 class WorkerInteractor(object):
     def __init__(self, config, channel):
@@ -210,19 +212,14 @@ def getinfodict():
     )
 
 
-def remote_initconfig(option_dict, args):
-    from _pytest.config import Config
-
-    option_dict["plugins"].append("no:terminal")
-    config = Config.fromdictargs(option_dict, args)
+def remote_initconfig(config, option_dict):
     config.option.looponfail = False
     config.option.usepdb = False
     config.option.dist = "no"
     config.option.distload = False
     config.option.numprocesses = None
     config.option.maxprocesses = None
-    config.args = args
-    return config
+    config.option.basetemp = option_dict.get('basetemp')
 
 
 if __name__ == "__channelexec__":
@@ -239,7 +236,8 @@ def remote_initconfig(option_dict, args):
     os.environ["PYTEST_XDIST_WORKER"] = workerinput["workerid"]
     os.environ["PYTEST_XDIST_WORKER_COUNT"] = str(workerinput["workercount"])
 
-    config = remote_initconfig(option_dict, args)
+    config = _prepareconfig(args, None)
+    remote_initconfig(config, option_dict)
     config._parser.prog = os.path.basename(workerinput["mainargv"][0])
     config.workerinput = workerinput
     config.workeroutput = {}

src/xdist/workermanage.py

@@ -236,10 +236,10 @@ def shutting_down(self):
     def setup(self):
         self.log("setting up worker session")
         spec = self.gateway.spec
-        args = self.config.args
+        args = sys.argv[1:]
         if not spec.popen or spec.chdir:
             args = make_reltoroot(self.nodemanager.roots, args)
-        option_dict = vars(self.config.option)
+        option_dict = {}
         if spec.popen:
             name = "popen-%s" % self.gateway.id
             if hasattr(self.config, "_tmpdirhandler"):

tox.ini

@@ -12,7 +12,7 @@ deps =
   pytestmaster: git+https://github.com/pytest-dev/pytest.git@master
   pytestfeatures: git+https://github.com/pytest-dev/pytest.git@features
 commands=
-  pytest {posargs}
+  pytest {posargs} --runpytest=subprocess
 
 [testenv:linting]
 skipsdist = True