Add new "pytest_modify_args" hook

AUTHORS

@@ -98,6 +98,7 @@ David Szotten
 David Vierra
 Daw-Ran Liou
 Debi Mishra
+Delgan
 Denis Kirisov
 Denivy Braiam Rück
 Dhiren Serai

changelog/9619.feature.rst

@@ -0,0 +1 @@
+Added a new ``pytest_modify_args`` hook.

doc/en/reference/reference.rst

@@ -627,6 +627,8 @@ Initialization hooks
 
 Initialization hooks called for plugins and ``conftest.py`` files.
 
+.. hook:: pytest_modify_args
+.. autofunction:: pytest_modify_args
 .. hook:: pytest_addoption
 .. autofunction:: pytest_addoption
 .. hook:: pytest_addhooks

src/_pytest/config/__init__.py

@@ -1318,6 +1318,7 @@ class Config:
             kwargs=dict(pluginmanager=self.pluginmanager)
         )
         self._preparse(args, addopts=addopts)
+        self.hook.pytest_modify_args(args=args)
         # XXX deprecated hook:
         self.hook.pytest_cmdline_preparse(config=self, args=args)
         self._parser.after_preparse = True  # type: ignore

src/_pytest/hookspec.py

@@ -172,6 +172,13 @@ def pytest_cmdline_preparse(config: "Config", args: List[str]) -> None:
     """
 
 
+def pytest_modify_args(args: List[str]) -> None:
+    """Modify command line arguments before option parsing.
+    
+    :param List[str] args: Arguments passed on the command line.
+    """
+
+
 @hookspec(firstresult=True)
 def pytest_cmdline_main(config: "Config") -> Optional[Union["ExitCode", int]]:
     """Called for performing the main command line action. The default

testing/test_config.py

@@ -1296,6 +1296,17 @@ def test_load_initial_conftest_last_ordering(_config_for_test):
     ]
 
 
+def test_modify_args_hook(pytester: Pytester) -> None:
+    pytester.makeconftest(
+        """
+        def pytest_modify_args(args):
+            args.append("-h")
+    """
+    )
+    result = pytester.runpytest()
+    result.stdout.fnmatch_lines(["*pytest*", "*-h*"])
+
+
 def test_get_plugin_specs_as_list() -> None:
     def exp_match(val: object) -> str:
         return (