pythonpath: make it compatible with pytest-pythonpath until pytest 8

Fix #9636.

changelog/9636.bugfix.rst

@@ -0,0 +1,2 @@
+Restore compatiblity to users of the pytest-pythonpath plugins by adding two ini options ``python_paths`` and ``site_dirs``.
+These options are immediately marked as deprecated. See :ref:`python_paths-site_dir-ini` for details.

doc/en/deprecations.rst

@@ -18,6 +18,24 @@ Deprecated Features
 Below is a complete list of all pytest features which are considered deprecated. Using those features will issue
 :class:`PytestWarning` or subclasses, which can be filtered using :ref:`standard warning filters <warnings>`.
 
+
+.. _python_paths-site_dir-ini:
+
+The ``python_paths`` and ``site_dirs`` ini options
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+.. deprecated:: 7.0.1
+
+These two deprecations are relevant for users of the pytest-pythonpath plugin.
+In pytest 7.0.0, a built-in ``pythonpath`` plugin was added with similar functionality to pytest-pythonpath.
+In pytest 7.0.1, it was found that the built-in plugin prevents the external pytest-pythonpath from loading,
+so to compensate, the options from the pytest-pythonpath plugins are implemented, but are immediately deprecated.
+
+The ``python_paths`` ini option is deprecated. Use :confval:`pythonpath` instead.
+
+The ``site_dirs`` ini option is deprecated. There is no replacement. If you use it, let the pytest developers know.
+
+
 .. _instance-collector-deprecation:
 
 The ``pytest.Instance`` collector

extra/setup-py.test/setup.py

@@ -1,4 +1,5 @@
 import sys
+
 from distutils.core import setup
 
 if __name__ == "__main__":

src/_pytest/deprecated.py

@@ -104,6 +104,17 @@ INSTANCE_COLLECTOR = PytestRemovedIn8Warning(
     "See https://docs.pytest.org/en/latest/deprecations.html#the-pytest-instance-collector",
 )
 
+PYTHON_PATHS_INI = PytestRemovedIn8Warning(
+    "The python_paths ini option is deprecated. Use the pythonpath ini option instead. "
+    "If you are using the pytest-pythonpath plugin, you can remove it - it is built-in since pytest 7.0.0. "
+    "See https://docs.pytest.org/en/latest/deprecations.html#python_paths-site_dir-ini",
+)
+
+SITE_DIRS_INI = PytestRemovedIn8Warning(
+    "The site_dirs ini option is deprecated. "
+    "See https://docs.pytest.org/en/latest/deprecations.html#python_paths-site_dir-ini",
+)
+
 # You want to make some `__init__` or function "private".
 #
 #   def my_private_function(some, args):

src/_pytest/pythonpath.py

@@ -1,24 +1,54 @@
 import sys
 
 import pytest
+from _pytest.deprecated import PYTHON_PATHS_INI
+from _pytest.deprecated import SITE_DIRS_INI
 from pytest import Config
 from pytest import Parser
 
 
 def pytest_addoption(parser: Parser) -> None:
     parser.addini("pythonpath", type="paths", help="Add paths to sys.path", default=[])
+    parser.addini(
+        "python_paths", type="paths", help="Deprecated alias for pythonpath", default=[]
+    )
+    parser.addini(
+        "site_dirs",
+        type="paths",
+        help="Deprecated: directory paths to add to via site.addsitedir(path)",
+        default=[],
+    )
 
 
 @pytest.hookimpl(tryfirst=True)
 def pytest_load_initial_conftests(early_config: Config) -> None:
+    pythonpath = early_config.getini("pythonpath")
+    python_paths = early_config.getini("python_paths")
+    if python_paths:
+        early_config.issue_config_time_warning(PYTHON_PATHS_INI, 2)
+        if not pythonpath:
+            pythonpath = python_paths
     # `pythonpath = a b` will set `sys.path` to `[a, b, x, y, z, ...]`
-    for path in reversed(early_config.getini("pythonpath")):
+    for path in reversed(pythonpath):
         sys.path.insert(0, str(path))
 
+    site_dirs = early_config.getini("site_dirs")
+    if site_dirs:
+        early_config.issue_config_time_warning(SITE_DIRS_INI, 2)
+
+        import site
+
+        for path in site_dirs:
+            site.addsitedir(str(path))
+
 
 @pytest.hookimpl(trylast=True)
 def pytest_unconfigure(config: Config) -> None:
-    for path in config.getini("pythonpath"):
+    pythonpath = config.getini("pythonpath")
+    python_paths = config.getini("python_paths")
+    if python_paths and not pythonpath:
+        pythonpath = python_paths
+    for path in pythonpath:
         path_str = str(path)
         if path_str in sys.path:
             sys.path.remove(path_str)