Fix provisioning

Signed-off-by: Bernát Gábor <bgabor8@bloomberg.net>

src/tox/config/main.py

@@ -132,10 +132,9 @@ def get_section_config(
         except KeyError:
             conf_set = of_type(self, section, for_env)
             self._key_to_conf_set[key] = conf_set
+            conf_set.loaders.extend(loaders or [])
             for loader in self._src.get_loaders(section, base, self._overrides, conf_set):
                 conf_set.loaders.append(loader)
-            if loaders is not None:
-                conf_set.loaders.extend(loaders)
             return conf_set
 
     def get_env(

src/tox/provision.py

@@ -8,7 +8,7 @@
 import sys
 from argparse import ArgumentParser
 from pathlib import Path
-from typing import TYPE_CHECKING, List, cast
+from typing import TYPE_CHECKING, List, Optional, cast
 
 from packaging.requirements import Requirement
 from packaging.utils import canonicalize_name
@@ -62,7 +62,7 @@ def provision(state: State) -> int | bool:
         keys=["min_version", "minversion"],
         of_type=Version,
         # do not include local version specifier (because it's not allowed in version spec per PEP-440)
-        default=Version("4.0"),
+        default=None,  # type: ignore # Optional[Version] translates to object
         desc="Define the minimal tox version required to run",
     )
     state.conf.core.add_config(
@@ -72,10 +72,10 @@ def provision(state: State) -> int | bool:
         desc="Name of the virtual environment used to provision a tox.",
     )
 
-    def add_tox_requires_min_version(requires: list[Requirement]) -> list[Requirement]:
+    def add_tox_requires_min_version(reqs: list[Requirement]) -> list[Requirement]:
         min_version: Version = state.conf.core["min_version"]
-        requires.append(Requirement(f"tox >= {min_version}"))
-        return requires
+        reqs.append(Requirement(f"tox{f'>={min_version}' if min_version else ''}"))
+        return reqs
 
     state.conf.core.add_config(
         keys="requires",

src/tox/session/env_select.py

@@ -232,11 +232,8 @@ def _finalize_config(self) -> None:
     def _build_run_env(self, name: str) -> RunToxEnv | None:
         if self._provision is not None and self._provision[0] is False and name == self._provision[1]:
             return None
-        env_conf = self._state.conf.get_env(
-            name,
-            package=False,
-            loaders=[self._provision[2]] if self._provision is not None and self._provision[1] == name else None,
-        )
+        loaders = [self._provision[2]] if self._provision is not None and self._provision[1] == name else None
+        env_conf = self._state.conf.get_env(name, package=False, loaders=loaders)
         desc = "the tox execute used to evaluate this environment"
         env_conf.add_config(keys="runner", desc=desc, of_type=str, default=self._state.conf.options.default_runner)
         runner = REGISTER.runner(cast(str, env_conf["runner"]))