From a70dace69cce08cb9e4f39768e018aa24f367eb7 Mon Sep 17 00:00:00 2001
From: Daniel Hahler <git@thequod.de>
Date: Sun, 9 Dec 2018 18:09:59 +0100
Subject: [PATCH] Pass and use original sys.argv to/with workers

This gets used e.g. by argparse for the "prog" part.

We could explicitly pass it through and/or set it on
config._parser.prog, but that is a bit tedious just for this use case,
and it looks like "simulating" the main prog here appears to not be that
bad of a hack after all.
---
 changelog/388.feature.rst |  3 ++
 testing/test_remote.py    | 67 +++++++++++++++++++++++++++++++++++++++
 xdist/remote.py           |  1 +
 xdist/workermanage.py     |  2 ++
 4 files changed, 73 insertions(+)
 create mode 100644 changelog/388.feature.rst

diff --git a/changelog/388.feature.rst b/changelog/388.feature.rst
new file mode 100644
index 00000000..57f59433
--- /dev/null
+++ b/changelog/388.feature.rst
@@ -0,0 +1,3 @@
+``mainargv`` is made available in ``workerinput`` from the host's ``sys.argv``.
+
+This can be used via ``request.config.workerinput["mainargv"]``.
diff --git a/testing/test_remote.py b/testing/test_remote.py
index dd6ee873..d0e4757c 100644
--- a/testing/test_remote.py
+++ b/testing/test_remote.py
@@ -1,6 +1,8 @@
+import os
 import py
 import pprint
 import pytest
+import sys
 
 from xdist.workermanage import WorkerController, unserialize_report
 from xdist.remote import serialize_report
@@ -397,3 +399,68 @@ def test():
     )
     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")
+    prog = os.path.basename(sys.argv[0])
+
+    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: %s *" % prog, "%s: error: my_usage_error" % prog]
+    )
diff --git a/xdist/remote.py b/xdist/remote.py
index a0afa49b..4050385f 100644
--- a/xdist/remote.py
+++ b/xdist/remote.py
@@ -261,6 +261,7 @@ def remote_initconfig(option_dict, args):
     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
diff --git a/xdist/workermanage.py b/xdist/workermanage.py
index c6f0010f..20cdad40 100644
--- a/xdist/workermanage.py
+++ b/xdist/workermanage.py
@@ -2,6 +2,7 @@
 import fnmatch
 import os
 import re
+import sys
 import threading
 
 import py
@@ -213,6 +214,7 @@ def __init__(self, nodemanager, gateway, config, putevent):
             "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