Fix plugin initialization order

docs/changelog/2264.bugfix.rst

@@ -0,0 +1 @@
+Fix plugin initialization order - core plugins first, then 3rd party and finally inline - by :user:`gaborbernat`.

src/tox/config/cli/parse.py

@@ -49,7 +49,7 @@ def _get_base(args: Sequence[str]) -> tuple[int, ToxHandler, Source]:
 
     source = discover_source(parsed.config_file, parsed.root_dir)
 
-    MANAGER.load_inline_plugin(source.path)
+    MANAGER.load_plugins(source.path)
 
     return guess_verbosity, handler, source
 

src/tox/plugin/manager.py

@@ -28,9 +28,13 @@ def __init__(self) -> None:
         self.manager: pluggy.PluginManager = pluggy.PluginManager(NAME)
         self.manager.add_hookspecs(spec)
 
+    def _register_plugins(self, inline: ModuleType | None) -> None:
         from tox.session import state
         from tox.session.cmd import depends, devenv, exec_, legacy, list_env, quickstart, show_config, version_flag
 
+        if inline is not None:
+            self.manager.register(inline)
+        self.manager.load_setuptools_entrypoints(NAME)
         internal_plugins = (
             loader_api,
             provision,
@@ -49,10 +53,8 @@ def __init__(self) -> None:
             sequential,
             package_api,
         )
-
         for plugin in internal_plugins:
             self.manager.register(plugin)
-        self.manager.load_setuptools_entrypoints(NAME)
         self.manager.register(state)
         self.manager.check_pending()
 
@@ -74,13 +76,12 @@ def tox_before_run_commands(self, tox_env: ToxEnv) -> None:
     def tox_after_run_commands(self, tox_env: ToxEnv, exit_code: int, outcomes: list[Outcome]) -> None:
         self.manager.hook.tox_after_run_commands(tox_env=tox_env, exit_code=exit_code, outcomes=outcomes)
 
-    def load_inline_plugin(self, path: Path) -> None:
-        result = _load_inline(path)
-        if result is not None:
-            self.manager.register(result)
+    def load_plugins(self, path: Path) -> None:
+        for _plugin in self.manager.get_plugins():  # make sure we start with a clean state, repeated in memory run
+            self.manager.unregister(_plugin)
+        inline = _load_inline(path)
+        self._register_plugins(inline)
         REGISTER._register_tox_env_types(self)
-        if result is not None:  #: recheck pending for the inline plugins
-            self.manager.check_pending()
 
 
 def _load_inline(path: Path) -> ModuleType | None:  # used to be able to unregister plugin tests

src/tox/pytest.py

@@ -81,10 +81,8 @@ def _disable_root_tox_py(request: SubRequest, mocker: MockerFixture) -> Iterator
 
         def _load_inline(path: Path) -> ModuleType | None:  # register only on first run, and unregister at end
             nonlocal module
-            if module is None:
-                module = load_inline(path)
-                return module
-            return None
+            module = load_inline(path)
+            return module
 
         mocker.patch.object(manager, "_load_inline", _load_inline)
         yield

src/tox/tox_env/register.py

@@ -22,8 +22,6 @@ def __init__(self) -> None:
 
     def _register_tox_env_types(self, manager: Plugin) -> None:
         manager.tox_register_tox_env(register=self)
-        if not self._default_run_env:
-            self._default_run_env = next(iter(self._run_envs.keys()))
 
     def add_run_env(self, of_type: type[RunToxEnv]) -> None:
         """
@@ -49,6 +47,8 @@ def env_runners(self) -> Iterable[str]:
     @property
     def default_env_runner(self) -> str:
         """:returns: the default run environment type"""
+        if not self._default_run_env and self._run_envs:
+            self._default_run_env = next(iter(self._run_envs.keys()))
         return self._default_run_env
 
     @default_env_runner.setter

tests/tox_env/test_register.py

@@ -13,8 +13,15 @@ def test_register_set_new_default_no_register() -> None:
 
 
 def test_register_set_new_default_with_register() -> None:
+    class B(VirtualEnvRunner):
+        @staticmethod
+        def id() -> str:
+            return "B"
+
     register = ToxEnvRegister()
     register.add_run_env(VirtualEnvRunner)
-    assert register.default_env_runner == ""
-    register.default_env_runner = VirtualEnvRunner.id()
-    assert register.default_env_runner == "virtualenv"
+    assert register.default_env_runner == VirtualEnvRunner.id()
+    register.add_run_env(B)
+    assert register.default_env_runner == VirtualEnvRunner.id()
+    register.default_env_runner = B.id()
+    assert register.default_env_runner == "B"

tox.ini

@@ -49,7 +49,7 @@ description = run type check on code base
 setenv =
     {tty:MYPY_FORCE_COLOR = 1}
 deps =
-    mypy==0.930
+    mypy==0.931
     types-cachetools
     types-chardet
     types-freezegun