Merge remote-tracking branch 'upstream/master' into release-1.25.0

Fix test_remote_usage_prog which started to break with pytest@features

.travis.yml

@@ -11,36 +11,36 @@ notifications:
   email:
   - pytest-commit@python.org
 
-python:
-- '2.7'
-- '3.4'
-- '3.5'
-- '3.6'
-env:
-- TOXENV=py-pytest30
-- TOXENV=py-pytest31
-- TOXENV=py-pytest32
-- TOXENV=py-pytest33
-- TOXENV=py-pytest36
-- TOXENV=py-pytest38
-
-install: pip install tox setuptools_scm
+install:
+  - pip install -U pip
+  - pip install tox setuptools_scm
 script: tox
 
 stages:
-- linting
+- baseline
 - test
 - name: deploy
   if: repo = pytest-dev/pytest-xdist AND tag IS present
 
 jobs:
   include:
-    - stage: linting
+    - stage: baseline
       python: '3.6'
-      script:
-      - tox -e linting
+      env: TOXENV=linting
+    - python: '3.6'
+      env: TOXENV=py36-pytestlatest
+    - python: '2.7'
+      env: TOXENV=py27-pytestlatest
+
     - stage: test
-    # python x env above are already included into this stage
+      python: "3.4"
+      env: TOXENV=py34-pytestlatest
+    - python: "3.5"
+      env: TOXENV=py35-pytestlatest
+    - python: "3.7"
+      env: TOXENV=py37-pytestlatest
+      sudo: required
+      dist: xenial
     - python: "2.7"
       env: TOXENV=py27-pytestmaster
     - python: "2.7"

CHANGELOG.rst

@@ -1,3 +1,67 @@
+pytest-xdist 1.25.0 (2018-12-12)
+================================
+
+Deprecations and Removals
+-------------------------
+
+- `#372 <https://github.com/pytest-dev/pytest-xdist/issues/372>`_: Pytest versions older than 3.6 are no longer supported.
+
+
+Features
+--------
+
+- `#373 <https://github.com/pytest-dev/pytest-xdist/issues/373>`_: Node setup information is hidden when pytest is run in quiet mode to reduce noise on many-core machines.
+
+- `#388 <https://github.com/pytest-dev/pytest-xdist/issues/388>`_: ``mainargv`` is made available in ``workerinput`` from the host's ``sys.argv``.
+
+  This can be used via ``request.config.workerinput["mainargv"]``.
+
+
+Bug Fixes
+---------
+
+- `#332 <https://github.com/pytest-dev/pytest-xdist/issues/332>`_: Fix report of module-level skips (``pytest.skip(reason, allow_module_level=True)``).
+
+- `#378 <https://github.com/pytest-dev/pytest-xdist/issues/378>`_: Fix support for gevent monkeypatching
+
+- `#384 <https://github.com/pytest-dev/pytest-xdist/issues/384>`_: pytest 4.1 support: ``ExceptionInfo`` API changes.
+
+- `#390 <https://github.com/pytest-dev/pytest-xdist/issues/390>`_: pytest 4.1 support: ``pytest_logwarning`` hook removed.
+
+
+pytest-xdist 1.24.1 (2018-11-09)
+================================
+
+Bug Fixes
+---------
+
+- `#349 <https://github.com/pytest-dev/pytest-xdist/issues/349>`_: Correctly handle warnings created with arguments that can't be serialized during the transfer from workers to master node.
+
+
+pytest-xdist 1.24.0 (2018-10-18)
+================================
+
+Features
+--------
+
+- `#337 <https://github.com/pytest-dev/pytest-xdist/issues/337>`_: New ``--maxprocesses`` command-line option that limits the maximum number of workers when using ``--numprocesses=auto``.
+
+
+Bug Fixes
+---------
+
+- `#351 <https://github.com/pytest-dev/pytest-xdist/issues/351>`_: Fix scheduling deadlock in case of inter-test locking.
+
+
+pytest-xdist 1.23.2 (2018-09-28)
+================================
+
+Bug Fixes
+---------
+
+- `#344 <https://github.com/pytest-dev/pytest-xdist/issues/344>`_: Fix issue where Warnings could cause pytest to fail if they do not set the args attribute correctly.
+
+
 pytest-xdist 1.23.1 (2018-09-25)
 ================================
 

appveyor.yml

@@ -1,22 +1,23 @@
 environment:
   matrix:
-  # note: please use "tox --listenvs" to populate the build matrix
-  - TOXENV: "py27-pytest33"
-  - TOXENV: "py34-pytest33"
-  - TOXENV: "py35-pytest33"
-  - TOXENV: "py36-pytest33"
-  - TOXENV: "py36-pytest36"
-  - TOXENV: "py36-pytest38"
-  - TOXENV: "py27-pytest33-pexpect"
-  - TOXENV: "py36-pytest33-pexpect"
+  - TOXENV: "py27-pytestlatest"
+  - TOXENV: "py34-pytestlatest"
+  - TOXENV: "py35-pytestlatest"
+  - TOXENV: "py36-pytestlatest"
+  - TOXENV: "py37-pytestlatest"
+  - TOXENV: "py27-pytestmaster"
+  - TOXENV: "py36-pytestmaster"
+  - TOXENV: "py27-pytestfeatures"
+  - TOXENV: "py36-pytestfeatures"
 
 install:
-  - C:\Python36\python -m pip install -U tox setuptools_scm pip
+  - C:\Python37\python -m pip install -U pip
+  - C:\Python37\python -m pip install -U tox setuptools_scm
 
 build: false  # Not a C# project, build stuff at the test step instead.
 
 test_script:
-  - C:\Python36\python -m tox
+  - C:\Python37\python -m tox
 
 # We don't deploy anything on tags with AppVeyor, we use Travis instead, so we
 # might as well save resources

setup.py

@@ -1,6 +1,6 @@
 from setuptools import setup, find_packages
 
-install_requires = ["execnet>=1.1", "pytest>=3.0.0", "pytest-forked", "six"]
+install_requires = ["execnet>=1.1", "pytest>=3.6.0", "pytest-forked", "six"]
 
 
 setup(
@@ -40,5 +40,6 @@ setup(
         "Programming Language :: Python :: 3.4",
         "Programming Language :: Python :: 3.5",
         "Programming Language :: Python :: 3.6",
+        "Programming Language :: Python :: 3.7",
     ],
 )

testing/acceptance_test.py

@@ -358,6 +358,30 @@ class TestDistEach:
 
 
 class TestTerminalReporting:
+    @pytest.mark.parametrize("verbosity", ["", "-q", "-v"])
+    def test_output_verbosity(self, testdir, verbosity):
+        testdir.makepyfile(
+            """
+            def test_ok():
+                pass
+        """
+        )
+        args = ["-n1"]
+        if verbosity:
+            args.append(verbosity)
+        result = testdir.runpytest(*args)
+        out = result.stdout.str()
+        if verbosity == "-v":
+            assert "scheduling tests" in out
+            assert "gw" in out
+        elif verbosity == "-q":
+            assert "scheduling tests" not in out
+            assert "gw" not in out
+            assert "bringing up nodes..." in out
+        else:
+            assert "scheduling tests" not in out
+            assert "gw" in out
+
     def test_pass_skip_fail(self, testdir):
         testdir.makepyfile(
             """
@@ -400,35 +424,6 @@ class TestTerminalReporting:
             ]
         )
 
-    @pytest.mark.parametrize("n", ["-n0", "-n1"])
-    @pytest.mark.parametrize("warn_type", ["pytest", "builtin"])
-    def test_warnings(self, testdir, n, warn_type):
-        from pkg_resources import parse_version
-
-        if parse_version(pytest.__version__) < parse_version("3.1"):
-            pytest.skip("pytest warnings requires >= 3.1")
-
-        if warn_type == "builtin":
-            warn_code = """warnings.warn(UserWarning('this is a warning'))"""
-        elif warn_type == "pytest":
-            warn_code = """request.config.warn('', 'this is a warning',
-                           fslocation=py.path.local())"""
-        else:
-            assert False
-        testdir.makepyfile(
-            """
-            import warnings, py, pytest
-
-            @pytest.mark.filterwarnings('ignore:config.warn has been deprecated')
-            def test_func(request):
-                {warn_code}
-        """.format(
-                warn_code=warn_code
-            )
-        )
-        result = testdir.runpytest(n)
-        result.stdout.fnmatch_lines(["*this is a warning*", "*1 passed, 1 warnings*"])
-
     def test_logfinish_hook(self, testdir):
         """Ensure the pytest_runtest_logfinish hook is being properly handled"""
         from _pytest import hookspec
@@ -546,16 +541,15 @@ def test_session_testscollected(testdir):
     assert collected_file.read() == "collected = 3"
 
 
-def test_funcarg_teardown_failure(testdir):
+def test_fixture_teardown_failure(testdir):
     p = testdir.makepyfile(
         """
         import pytest
-        @pytest.fixture
+        @pytest.fixture(scope="module")
         def myarg(request):
-            def teardown(val):
-                raise ValueError(val)
-            return request.cached_setup(setup=lambda: 42, teardown=teardown,
-                scope="module")
+            yield 42
+            raise ValueError(42)
+
         def test_hello(myarg):
             pass
     """
@@ -641,6 +635,11 @@ def test_skipping(testdir):
 
 
 def test_issue34_pluginloading_in_subprocess(testdir):
+    import _pytest.hookspec
+
+    if not hasattr(_pytest.hookspec, "pytest_namespace"):
+        pytest.skip("this pytest version no longer supports pytest_namespace()")
+
     testdir.tmpdir.join("plugin123.py").write(
         textwrap.dedent(
             """
@@ -736,6 +735,73 @@ def test_sub_plugins_disabled(testdir, plugin):
     result.stdout.fnmatch_lines("*1 passed*")
 
 
+class TestWarnings:
+    @pytest.mark.parametrize("n", ["-n0", "-n1"])
+    @pytest.mark.parametrize("warn_type", ["pytest", "builtin"])
+    def test_warnings(self, testdir, n, warn_type):
+        if warn_type == "builtin":
+            warn_code = """warnings.warn(UserWarning('this is a warning'))"""
+        elif warn_type == "pytest":
+            warn_code = """request.config.warn('', 'this is a warning',
+                           fslocation=py.path.local())"""
+        else:
+            assert False
+        testdir.makepyfile(
+            """
+            import warnings, py, pytest
+
+            @pytest.mark.filterwarnings('ignore:config.warn has been deprecated')
+            def test_func(request):
+                {warn_code}
+        """.format(
+                warn_code=warn_code
+            )
+        )
+        result = testdir.runpytest(n)
+        result.stdout.fnmatch_lines(["*this is a warning*", "*1 passed, 1 warnings*"])
+
+    @pytest.mark.parametrize("n", ["-n0", "-n1"])
+    def test_custom_subclass(self, testdir, n):
+        """Check that warning subclasses that don't honor the args attribute don't break
+        pytest-xdist (#344)
+        """
+        testdir.makepyfile(
+            """
+            import warnings, py, pytest
+
+            class MyWarning(UserWarning):
+
+                def __init__(self, p1, p2):
+                    self.p1 = p1
+                    self.p2 = p2
+                    self.args = ()
+
+            def test_func(request):
+                warnings.warn(MyWarning("foo", 1))
+        """
+        )
+        testdir.syspathinsert()
+        result = testdir.runpytest(n)
+        result.stdout.fnmatch_lines(["*MyWarning*", "*1 passed, 1 warnings*"])
+
+    @pytest.mark.parametrize("n", ["-n0", "-n1"])
+    def test_unserializable_arguments(self, testdir, n):
+        """Check that warnings with unserializable arguments are handled correctly (#349)."""
+        testdir.makepyfile(
+            """
+            import warnings, pytest
+
+            def test_func(tmpdir):
+                fn = (tmpdir / 'foo.txt').ensure(file=1)
+                with fn.open('r') as f:
+                    warnings.warn(UserWarning("foo", f))
+        """
+        )
+        testdir.syspathinsert()
+        result = testdir.runpytest(n)
+        result.stdout.fnmatch_lines(["*UserWarning*foo.txt*", "*1 passed, 1 warnings*"])
+
+
 class TestNodeFailure:
     def test_load_single(self, testdir):
         f = testdir.makepyfile(
@@ -1103,6 +1169,56 @@ class TestFileScope:
         assert c1 == c2
 
 
+class TestLocking:
+    _test_content = """
+    class TestClassName%s(object):
+
+        @classmethod
+        def setup_class(cls):
+            FILE_LOCK.acquire()
+
+        @classmethod
+        def teardown_class(cls):
+            FILE_LOCK.release()
+
+        def test_a(self):
+            pass
+
+        def test_b(self):
+            pass
+
+        def test_c(self):
+            pass
+
+    """
+
+    test_file1 = """
+    import filelock
+
+    FILE_LOCK = filelock.FileLock("test.lock")
+
+    """ + (
+        (_test_content * 4) % ("A", "B", "C", "D")
+    )
+
+    @pytest.mark.parametrize("scope", ["each", "load", "loadscope", "loadfile", "no"])
+    def test_single_file(self, testdir, scope):
+        testdir.makepyfile(test_a=self.test_file1)
+        result = testdir.runpytest("-n2", "--dist=%s" % scope, "-v")
+        result.assert_outcomes(passed=(12 if scope != "each" else 12 * 2))
+
+    @pytest.mark.parametrize("scope", ["each", "load", "loadscope", "loadfile", "no"])
+    def test_multi_file(self, testdir, scope):
+        testdir.makepyfile(
+            test_a=self.test_file1,
+            test_b=self.test_file1,
+            test_c=self.test_file1,
+            test_d=self.test_file1,
+        )
+        result = testdir.runpytest("-n2", "--dist=%s" % scope, "-v")
+        result.assert_outcomes(passed=(48 if scope != "each" else 48 * 2))
+
+
 def parse_tests_and_workers_from_output(lines):
     result = []
     for line in lines:

testing/test_looponfail.py

@@ -1,4 +1,7 @@
 import py
+import pytest
+from pkg_resources import parse_version
+
 from xdist.looponfail import RemoteControl
 from xdist.looponfail import StatRecorder
 
@@ -214,7 +217,11 @@ class TestLooponFailing:
         assert "test_one" not in remotecontrol.failures[0]
         assert "test_two" in remotecontrol.failures[0]
 
-    @py.test.mark.xfail(py.test.__version__ >= "3.1", reason="broken by pytest 3.1+")
+    @pytest.mark.xfail(
+        parse_version(pytest.__version__) >= parse_version("3.1"),
+        reason="broken by pytest 3.1+",
+        strict=True,
+    )
     def test_looponfail_removed_test(self, testdir):
         modcol = testdir.getmodulecol(
             """

testing/test_plugin.py

@@ -25,6 +25,10 @@ def test_dist_options(testdir):
     check_options(config)
     assert config.option.dist == "load"
     assert config.option.tx == ["popen"] * 2
+    config = testdir.parseconfigure("--numprocesses", "3", "--maxprocesses", "2")
+    check_options(config)
+    assert config.option.dist == "load"
+    assert config.option.tx == ["popen"] * 2
     config = testdir.parseconfigure("-d")
     check_options(config)
     assert config.option.dist == "load"

testing/test_remote.py

@@ -1,6 +1,8 @@
 import py
 import pprint
 import pytest
+import sys
+
 from xdist.workermanage import WorkerController, unserialize_report
 from xdist.remote import serialize_report
 import execnet
@@ -292,14 +294,11 @@ class TestWorkerInteractor:
         ev = worker.popevent("workerfinished")
         assert "workeroutput" in ev.kwargs
 
-    @pytest.mark.skipif(
-        pytest.__version__ >= "3.0", reason="skip at module level illegal in pytest 3.0"
-    )
     def test_remote_collect_skip(self, worker):
         worker.testdir.makepyfile(
             """
-            import py
-            py.test.skip("hello")
+            import pytest
+            pytest.skip("hello", allow_module_level=True)
         """
         )
         worker.setup()
@@ -307,10 +306,9 @@ class TestWorkerInteractor:
         assert not ev.kwargs
         ev = worker.popevent()
         assert ev.name == "collectreport"
-        ev = worker.popevent()
-        assert ev.name == "collectreport"
         rep = unserialize_report(ev.name, ev.kwargs["data"])
         assert rep.skipped
+        assert rep.longrepr[2] == "Skipped: hello"
         ev = worker.popevent("collectionfinish")
         assert not ev.kwargs["ids"]
 
@@ -400,3 +398,66 @@ def test_remote_env_vars(testdir):
     )
     result = testdir.runpytest("-n2", "--max-worker-restart=0")
     assert result.ret == 0
+
+
+def test_remote_inner_argv(testdir):
+    """Test/document the behavior due to execnet using `python -c`."""
+    testdir.makepyfile(
+        """
+        import sys
+
+        def test_argv():
+            assert sys.argv == ["-c"]
+        """
+    )
+    result = testdir.runpytest("-n1")
+    assert result.ret == 0
+
+
+def test_remote_mainargv(testdir):
+    outer_argv = sys.argv
+
+    testdir.makepyfile(
+        """
+        def test_mainargv(request):
+            assert request.config.workerinput["mainargv"] == {!r}
+        """.format(
+            outer_argv
+        )
+    )
+    result = testdir.runpytest("-n1")
+    assert result.ret == 0
+
+
+def test_remote_usage_prog(testdir, request):
+    if not hasattr(request.config._parser, "prog"):
+        pytest.skip("prog not available in config parser")
+    testdir.makeconftest(
+        """
+        import pytest
+
+        config_parser = None
+
+        @pytest.fixture
+        def get_config_parser():
+            return config_parser
+
+        def pytest_configure(config):
+            global config_parser
+            config_parser = config._parser
+    """
+    )
+    testdir.makepyfile(
+        """
+        import sys
+
+        def test(get_config_parser, request):
+            get_config_parser._getparser().error("my_usage_error")
+    """
+    )
+
+    result = testdir.runpytest_subprocess("-n1")
+    assert result.ret == 1
+    result.stdout.fnmatch_lines(
+        ["usage: pytest.py *", "pytest.py: error: my_usage_error"]
+    )

tox.ini

@@ -1,33 +1,18 @@
 [tox]
-# if you change the envlist, please update .travis.yml file as well
 envlist=
   linting
-  py{27,34,35,36}-pytest{30,31,32,33,36,38}
-  py{27,36}-pytest36-pexpect
+  py{27,34,35,36,37}-pytestlatest
   py{27,36}-pytest{master,features}
 
-
 [testenv]
 changedir=testing
 passenv = USER USERNAME
 deps =
-  pycmd
-  # to avoid .eggs
-  setuptools_scm
-  pytest30: pytest~=3.0.5
-  pytest31: pytest~=3.1.0
-  pytest32: pytest~=3.2.0
-  pytest33: pytest~=3.3.0
-  pytest36: pytest~=3.6.0
-  pytest38: pytest~=3.8.0
+  pytestlatest: pytest
   pytestmaster: git+https://github.com/pytest-dev/pytest.git@master
   pytestfeatures: git+https://github.com/pytest-dev/pytest.git@features
-  pexpect: pexpect
-platform=
-  pexpect: linux|darwin
+  filelock
 commands=
-  # always clean to avoid code unmarshal mismatch on old python/pytest
-  py.cleanup -aq
   pytest {posargs}
 
 [testenv:linting]
@@ -50,7 +35,7 @@ commands =
     towncrier --version {posargs} --yes
 
 [pytest]
-addopts = -rsfxX
+addopts = -ra
 
 [flake8]
 max-line-length = 120

xdist/dsession.py

@@ -229,9 +229,10 @@ class DSession(object):
             if self.terminal and not self.sched.has_pending:
                 self.trdist.ensure_show_status()
                 self.terminal.write_line("")
-                self.terminal.write_line(
-                    "scheduling tests via %s" % (self.sched.__class__.__name__)
-                )
+                if self.config.option.verbose > 0:
+                    self.terminal.write_line(
+                        "scheduling tests via %s" % (self.sched.__class__.__name__)
+                    )
             self.sched.schedule()
 
     def worker_logstart(self, node, nodeid, location):
@@ -259,10 +260,10 @@ class DSession(object):
     def worker_collectreport(self, node, rep):
         """Emitted when a node calls the pytest_collectreport hook.
 
-        Because we only need the report when there's a failure, as optimization
-        we only expect to receive failed reports from workers (#330).
+        Because we only need the report when there's a failure/skip, as optimization
+        we only expect to receive failed/skipped reports from workers (#330).
         """
-        assert rep.failed
+        assert not rep.passed
         self._failed_worker_collectreport(node, rep)
 
     def worker_logwarning(self, message, code, nodeid, fslocation):
@@ -344,8 +345,11 @@ class TerminalDistReporter(object):
             self.rewrite(self.getstatus())
 
     def getstatus(self):
-        parts = ["%s %s" % (spec.id, self._status[spec.id]) for spec in self._specs]
-        return " / ".join(parts)
+        if self.config.option.verbose >= 0:
+            parts = ["%s %s" % (spec.id, self._status[spec.id]) for spec in self._specs]
+            return " / ".join(parts)
+        else:
+            return "bringing up nodes..."
 
     def rewrite(self, line, newline=False):
         pline = line + " " * max(self._lastlen - len(line), 0)

xdist/looponfail.py

@@ -32,7 +32,7 @@ def pytest_cmdline_main(config):
     if config.getoption("looponfail"):
         usepdb = config.getoption("usepdb")  # a core option
         if usepdb:
-            raise pytest.UsageError("--pdb incompatible with --looponfail.")
+            raise pytest.UsageError("--pdb is incompatible with --looponfail.")
         looponfail_main(config)
         return 2  # looponfail only can get stop with ctrl-C anyway
 

xdist/plugin.py

@@ -47,6 +47,14 @@ def pytest_addoption(parser):
         "you can use 'auto' here for auto detection CPUs number on "
         "host system",
     )
+    group.addoption(
+        "--maxprocesses",
+        dest="maxprocesses",
+        metavar="maxprocesses",
+        action="store",
+        type=int,
+        help="limit the maximum number of workers to process the tests when using --numprocesses=auto",
+    )
     group.addoption(
         "--max-worker-restart",
         "--max-slave-restart",
@@ -118,12 +126,12 @@ def pytest_addoption(parser):
     )
     parser.addini(
         "rsyncdirs",
-        "list of (relative) paths to be rsynced for" " remote distributed testing.",
+        "list of (relative) paths to be rsynced for remote distributed testing.",
         type="pathlist",
     )
     parser.addini(
         "rsyncignore",
-        "list of (relative) glob-style paths to be ignored " "for rsyncing.",
+        "list of (relative) glob-style paths to be ignored for rsyncing.",
         type="pathlist",
     )
     parser.addini(
@@ -172,7 +180,10 @@ def pytest_cmdline_main(config):
     if config.option.numprocesses:
         if config.option.dist == "no":
             config.option.dist = "load"
-        config.option.tx = ["popen"] * config.option.numprocesses
+        numprocesses = config.option.numprocesses
+        if config.option.maxprocesses:
+            numprocesses = min(numprocesses, config.option.maxprocesses)
+        config.option.tx = ["popen"] * numprocesses
     if config.option.distload:
         config.option.dist = "load"
     val = config.getvalue

xdist/remote.py

@@ -12,6 +12,7 @@ import time
 
 import _pytest.hookspec
 import pytest
+from execnet.gateway_base import dumps, DumpError
 
 
 class WorkerInteractor(object):
@@ -109,19 +110,22 @@ class WorkerInteractor(object):
         self.sendevent("testreport", data=data)
 
     def pytest_collectreport(self, report):
-        # master only needs reports that failed, as optimization send only them instead (#330)
-        if report.failed:
+        # send only reports that have not passed to master as optimization (#330)
+        if not report.passed:
             data = serialize_report(report)
             self.sendevent("collectreport", data=data)
 
-    def pytest_logwarning(self, message, code, nodeid, fslocation):
-        self.sendevent(
-            "logwarning",
-            message=message,
-            code=code,
-            nodeid=nodeid,
-            fslocation=str(fslocation),
-        )
+    # the pytest_logwarning hook was removed in pytest 4.1
+    if hasattr(_pytest.hookspec, "pytest_logwarning"):
+
+        def pytest_logwarning(self, message, code, nodeid, fslocation):
+            self.sendevent(
+                "logwarning",
+                message=message,
+                code=code,
+                nodeid=nodeid,
+                fslocation=str(fslocation),
+            )
 
     # the pytest_warning_captured hook was introduced in pytest 3.8
     if hasattr(_pytest.hookspec, "pytest_warning_captured"):
@@ -181,8 +185,15 @@ def serialize_warning_message(warning_message):
     if isinstance(warning_message.message, Warning):
         message_module = type(warning_message.message).__module__
         message_class_name = type(warning_message.message).__name__
-        message_args = warning_message.message.args
-        message_str = None
+        message_str = str(warning_message.message)
+        # check now if we can serialize the warning arguments (#349)
+        # if not, we will just use the exception message on the master node
+        try:
+            dumps(warning_message.message.args)
+        except DumpError:
+            message_args = None
+        else:
+            message_args = warning_message.message.args
     else:
         message_str = warning_message.message
         message_module = None
@@ -234,6 +245,7 @@ def remote_initconfig(option_dict, args):
     config.option.dist = "no"
     config.option.distload = False
     config.option.numprocesses = None
+    config.option.maxprocesses = None
     config.args = args
     return config
 
@@ -252,6 +264,7 @@ if __name__ == "__channelexec__":
     import py
 
     config = remote_initconfig(option_dict, args)
+    config._parser.prog = os.path.basename(workerinput["mainargv"][0])
     config.workerinput = workerinput
     config.workeroutput = {}
     # TODO: deprecated name, backward compatibility only. Remove it in future

xdist/scheduler/__init__.py

@@ -1,4 +1,4 @@
 from xdist.scheduler.each import EachScheduling  # noqa
 from xdist.scheduler.load import LoadScheduling  # noqa
+from xdist.scheduler.loadfile import LoadFileScheduling  # noqa
 from xdist.scheduler.loadscope import LoadScopeScheduling  # noqa
-from xdist.scheduler.filescope import LoadFileScheduling  # noqa

xdist/scheduler/each.py

@@ -126,6 +126,7 @@ class EachScheduling(object):
             if not pending:
                 pending[:] = range(len(self.node2collection[node]))
                 node.send_runtest_all()
+                node.shutdown()
             else:
                 node.send_runtest_some(pending)
             self._started.append(node)

xdist/scheduler/load.py

@@ -178,6 +178,9 @@ class LoadScheduling(object):
                     return
                 num_send = items_per_node_max - len(node_pending)
                 self._send_tests(node, num_send)
+        else:
+            node.shutdown()
+
         self.log("num items waiting for node:", len(self.pending))
 
     def remove_node(self, node):

xdist/scheduler/loadfile.py

@@ -1,4 +1,4 @@
-from . import LoadScopeScheduling
+from .loadscope import LoadScopeScheduling
 from py.log import Producer
 
 

xdist/scheduler/loadscope.py

@@ -187,7 +187,7 @@ class LoadScopeScheduling(object):
             break
         else:
             raise RuntimeError(
-                "Unable to identify crashitem on a workload with " "pending items"
+                "Unable to identify crashitem on a workload with pending items"
             )
 
         # Made uncompleted work unit available again
@@ -306,6 +306,7 @@ class LoadScopeScheduling(object):
 
         # Check that more work is available
         if not self.workqueue:
+            node.shutdown()
             return
 
         self.log("Number of units waiting for node:", len(self.workqueue))

xdist/workermanage.py

@@ -2,6 +2,7 @@ from __future__ import print_function
 import fnmatch
 import os
 import re
+import sys
 import threading
 
 import py
@@ -213,6 +214,7 @@ class WorkerController(object):
             "workercount": len(nodemanager.specs),
             "slaveid": gateway.id,
             "slavecount": len(nodemanager.specs),
+            "mainargv": sys.argv,
         }
         # TODO: deprecated name, backward compatibility only. Remove it in future
         self.slaveinput = self.workerinput
@@ -268,7 +270,7 @@ class WorkerController(object):
         if not self._down:
             try:
                 self.sendcommand("shutdown")
-            except IOError:
+            except (IOError, OSError):
                 pass
             self._shutdown_sent = True
 
@@ -345,7 +347,11 @@ class WorkerController(object):
         except:  # noqa
             from _pytest._code import ExceptionInfo
 
-            excinfo = ExceptionInfo()
+            # ExceptionInfo API changed in pytest 4.1
+            if hasattr(ExceptionInfo, "from_current"):
+                excinfo = ExceptionInfo.from_current()
+            else:
+                excinfo = ExceptionInfo()
             print("!" * 20, excinfo)
             self.config.notify_exception(excinfo)
             self.shutdown()
@@ -426,7 +432,22 @@ def unserialize_warning_message(data):
     if data["message_module"]:
         mod = importlib.import_module(data["message_module"])
         cls = getattr(mod, data["message_class_name"])
-        message = cls(*data["message_args"])
+        message = None
+        if data["message_args"] is not None:
+            try:
+                message = cls(*data["message_args"])
+            except TypeError:
+                pass
+        if message is None:
+            # could not recreate the original warning instance;
+            # create a generic Warning instance with the original
+            # message at least
+            message_text = "{mod}.{cls}: {msg}".format(
+                mod=data["message_module"],
+                cls=data["message_class_name"],
+                msg=data["message_str"],
+            )
+            message = Warning(message_text)
     else:
         message = data["message_str"]