[WIP] load_entrypoint_plugins option/marker

doc/en/reference.rst

@@ -1103,6 +1103,18 @@ passed multiple times. The expected format is ``name=value``. For example::
         [pytest]
         junit_suite_name = my_suite
 
+.. confval:: load_entrypoint_plugins
+
+    .. versionadded:: 4.4
+
+    A list of pytest plugins that should be loaded via entrypoints.
+
+    By default all plugins are loaded. An empty list can be used to load none.
+
+    .. code-block:: ini
+
+        [pytest]
+        load_entrypoint_plugins = pytester,anotherplugin
 
 .. confval:: log_cli_date_format
 

src/_pytest/config/__init__.py

@@ -154,15 +154,17 @@ def directory_arg(path, optname):
 def get_config(args=None):
     # subsequent calls to main will create a fresh instance
     pluginmanager = PytestPluginManager()
-    config = Config(pluginmanager)
+    # XXX: storing it on the instance is required to make it available in
+    # is_blocked, which is the callback used with load_entrypoint_plugins.
+    pluginmanager.config = Config(pluginmanager)
 
     if args is not None:
         # Handle any "-p no:plugin" args.
         pluginmanager.consider_preparse(args)
 
     for spec in default_plugins:
         pluginmanager.import_plugin(spec)
-    return config
+    return pluginmanager.config
 
 
 def get_plugin_manager():
@@ -246,6 +248,20 @@ def __init__(self):
         # Used to know when we are importing conftests after the pytest_configure stage
         self._configured = False
 
+    def is_blocked(self, name):
+        ret = super(PytestPluginManager, self).is_blocked(name)
+        if not ret:
+            try:
+                config = self.config
+            except AttributeError:
+                pass
+            else:
+                load_entrypoint_plugins = config.getini("load_entrypoint_plugins")
+                if load_entrypoint_plugins is not notset:
+                    if name not in load_entrypoint_plugins:
+                        return True
+        return ret
+
     def addhooks(self, module_or_class):
         """
         .. deprecated:: 2.8
@@ -334,6 +350,14 @@ def hasplugin(self, name):
         """Return True if the plugin with the given name is registered."""
         return bool(self.get_plugin(name))
 
+    def pytest_addoption(self, parser):
+        parser.addini(
+            "load_entrypoint_plugins",
+            help="only load specified plugins via entrypoint",
+            default=notset,
+            type="args",
+        )
+
     def pytest_configure(self, config):
         # XXX now that the pluginmanager exposes hookimpl(tryfirst...)
         # we should remove tryfirst/trylast as markers
@@ -792,6 +816,10 @@ def _mark_plugins_for_rewrite(self, hook):
 
         self.pluginmanager.rewrite_hook = hook
 
+        load_entrypoint_plugins = self.getini("load_entrypoint_plugins")
+        if load_entrypoint_plugins is not notset and not len(load_entrypoint_plugins):
+            return
+
         if os.environ.get("PYTEST_DISABLE_PLUGIN_AUTOLOAD"):
             # We don't autoload from setuptools entry points, no need to continue.
             return
@@ -810,7 +838,8 @@ def _mark_plugins_for_rewrite(self, hook):
         )
 
         for name in _iter_rewritable_modules(package_files):
-            hook.mark_rewrite(name)
+            if load_entrypoint_plugins is notset or name in load_entrypoint_plugins:
+                hook.mark_rewrite(name)
 
     def _validate_args(self, args, via):
         """Validate known args."""
@@ -944,7 +973,7 @@ def _getini(self, name):
         if value is None:
             try:
                 value = self.inicfg[name]
-            except KeyError:
+            except (AttributeError, KeyError):
                 if default is not None:
                     return default
                 if type is None:

tox.ini

@@ -140,6 +140,7 @@ commands = python scripts/release.py {posargs}
 [pytest]
 minversion = 2.0
 addopts = -ra -p pytester
+load_entrypoint_plugins=pytester xdist
 rsyncdirs = tox.ini doc src testing
 python_files = test_*.py *_test.py testing/*/*.py
 python_classes = Test Acceptance