Deprecate pytest.config

Author: asottile

changelog/3050.deprecation.rst

@@ -0,0 +1 @@
+Deprecate ``pytest.config`` global.  See https://docs.pytest.org/en/latest/deprecations.html#pytest-config-global

doc/en/deprecations.rst

@@ -14,6 +14,15 @@ Below is a complete list of all pytest features which are considered deprecated.
 :class:`_pytest.warning_types.PytestWarning` or subclasses, which can be filtered using
 :ref:`standard warning filters <warnings>`.
 
+``pytest.config`` global
+~~~~~~~~~~~~~~~~~~~~~~~~
+
+.. deprecated:: 4.1
+
+The ``pytest.config`` global object is deprecated.  Instead use
+``request.config`` (via the ``request`` fixture) or if you are a plugin author
+use the ``pytest_configure(config)`` hook.
+
 .. _raises-warns-exec:
 
 ``raises`` / ``warns`` with a string as the second argument

src/_pytest/deprecated.py

@@ -97,6 +97,10 @@
     "Please move it to the top level conftest file instead."
 )
 
+PYTEST_CONFIG_GLOBAL = PytestDeprecationWarning(
+    "the `pytest.config` global is deprecated.  Please use `request.config` "
+    "or `pytest_configure` (if you're a pytest plugin) instead."
+)
 
 PYTEST_ENSURETEMP = RemovedInPytest4Warning(
     "pytest/tmpdir_factory.ensuretemp is deprecated, \n"

src/_pytest/main.py

@@ -8,6 +8,7 @@
 import os
 import pkgutil
 import sys
+import warnings
 
 import attr
 import py
@@ -18,6 +19,7 @@
 from _pytest.config import directory_arg
 from _pytest.config import hookimpl
 from _pytest.config import UsageError
+from _pytest.deprecated import PYTEST_CONFIG_GLOBAL
 from _pytest.outcomes import exit
 from _pytest.runner import collect_one_node
 
@@ -167,8 +169,24 @@ def pytest_addoption(parser):
     )
 
 
+class _ConfigDeprecated(object):
+    def __init__(self, config):
+        self.__dict__["_config"] = config
+
+    def __getattr__(self, attr):
+        warnings.warn(PYTEST_CONFIG_GLOBAL, stacklevel=2)
+        return getattr(self._config, attr)
+
+    def __setattr__(self, attr, val):
+        warnings.warn(PYTEST_CONFIG_GLOBAL, stacklevel=2)
+        return setattr(self._config, attr, val)
+
+    def __repr__(self):
+        return "{}({!r})".format(type(self).__name__, self._config)
+
+
 def pytest_configure(config):
-    __import__("pytest").config = config  # compatibility
+    __import__("pytest").config = _ConfigDeprecated(config)  # compatibility
 
 
 def wrap_session(config, doit):

testing/test_terminal.py

@@ -539,7 +539,7 @@ def test_method(self):
         result.stdout.fnmatch_lines(["test_passes.py ..*", "* 2 pass*"])
         assert result.ret == 0
 
-    def test_header_trailer_info(self, testdir):
+    def test_header_trailer_info(self, testdir, request):
         testdir.makepyfile(
             """
             def test_passes():
@@ -563,7 +563,7 @@ def test_passes():
                 "=* 1 passed*in *.[0-9][0-9] seconds *=",
             ]
         )
-        if pytest.config.pluginmanager.list_plugin_distinfo():
+        if request.config.pluginmanager.list_plugin_distinfo():
             result.stdout.fnmatch_lines(["plugins: *"])
 
     def test_showlocals(self, testdir):