Revert "Add multi env variable support to configs (pytorch#145288)"

This reverts commit a8b7cb6.

Reverted pytorch#145288 on behalf of https://github.com/huydhn due to Sorry for reverting your change but it is failing lint from a landrace with some recent PEP585 changes ([comment](pytorch#145288 (comment)))

Author: pytorchmergebot

test/test_utils_config_module.py

@@ -100,10 +100,6 @@ def test_env_name_semantics(self):
         config.e_env_force = False
         self.assertTrue(config.e_env_force)
 
-    def test_multi_env(self):
-        self.assertTrue(config2.e_env_default_multi)
-        self.assertTrue(config2.e_env_force_multi)
-
     def test_save_config(self):
         p = config.save_config()
         self.assertDictEqual(

torch/testing/_internal/fake_config_module2.py

@@ -1,13 +1,8 @@
 import sys
 
-from torch.utils._config_module import Config, install_config_module
+from torch.utils._config_module import install_config_module
 
 
 e_aliasing_bool = False
 
-e_env_default_multi: bool = Config(
-    env_name_default=["ENV_TRUE", "ENV_FALSE"], default=False
-)
-e_env_force_multi: bool = Config(env_name_force=["ENV_FAKE", "ENV_TRUE"], default=False)
-
 install_config_module(sys.modules[__name__])

torch/utils/_config_module.py

@@ -53,14 +53,10 @@ class _Config(Generic[T]):
         alias: If set, the directly use the value of the alias.
         env_name_force: If set, this environment variable has precedence over
             everything after this.
-            If multiple env variables are given, the precendence order is from
-            left to right.
         user_override: If a user sets a value (i.e. foo.bar=True), that
             has precedence over everything after this.
         env_name_default: If set, this environment variable will override everything
             after this.
-            If multiple env variables are given, the precendence order is from
-            left to right.
         justknob: If this pytorch installation supports justknobs, that will
             override defaults, but will not override the user_override precendence.
         default: This value is the lowest precendance, and will be used if nothing is
@@ -73,35 +69,33 @@ class _Config(Generic[T]):
         justknob: the name of the feature / JK. In OSS this is unused.
         default: is the value to default this knob to in OSS.
         alias: The alias config to read instead.
-        env_name_force: The environment variable, or list of, to read that is a FORCE
+        env_name_force: The environment variable to read that is a FORCE
             environment variable. I.e. it overrides everything except for alias.
-        env_name_default: The environment variable, or list of, to read that changes the
+        env_name_default: The environment variable to read that changes the
             default behaviour. I.e. user overrides take preference.
     """
 
     default: Union[T, object]
     justknob: Optional[str] = None
-    env_name_default: Optional[List[str]] = None
-    env_name_force: Optional[List[str]] = None
+    env_name_default: Optional[str] = None
+    env_name_force: Optional[str] = None
     value_type: Optional[type] = None
     alias: Optional[str] = None
 
     def __init__(
         self,
         default: Union[T, object] = _UNSET_SENTINEL,
         justknob: Optional[str] = None,
-        env_name_default: Optional[Union[str, List[str]]] = None,
-        env_name_force: Optional[Union[str, List[str]]] = None,
+        env_name_default: Optional[str] = None,
+        env_name_force: Optional[str] = None,
         value_type: Optional[type] = None,
         alias: Optional[str] = None,
     ):
         # python 3.9 does not support kw_only on the dataclass :(.
         self.default = default
         self.justknob = justknob
-        self.env_name_default = _Config.string_or_list_of_string_to_list(
-            env_name_default
-        )
-        self.env_name_force = _Config.string_or_list_of_string_to_list(env_name_force)
+        self.env_name_default = env_name_default
+        self.env_name_force = env_name_force
         self.value_type = value_type
         self.alias = alias
         if self.justknob is not None:
@@ -116,17 +110,6 @@ def __init__(
                 and env_name_force is None
             ), "if alias is set, default, justknob or env var cannot be set"
 
-    @staticmethod
-    def string_or_list_of_string_to_list(
-        val: Optional[Union[str, List[str]]]
-    ) -> Optional[List[str]]:
-        if val is None:
-            return None
-        if isinstance(val, str):
-            return [val]
-        assert isinstance(val, list)
-        return val
-
 
 # In runtime, we unbox the Config[T] to a T, but typechecker cannot see this,
 # so in order to allow for this dynamic behavior to work correctly with
@@ -137,8 +120,8 @@ def string_or_list_of_string_to_list(
     def Config(
         default: Union[T, object] = _UNSET_SENTINEL,
         justknob: Optional[str] = None,
-        env_name_default: Optional[Union[str, List[str]]] = None,
-        env_name_force: Optional[Union[str, List[str]]] = None,
+        env_name_default: Optional[str] = None,
+        env_name_force: Optional[str] = None,
         value_type: Optional[type] = None,
         alias: Optional[str] = None,
     ) -> T:
@@ -149,8 +132,8 @@ def Config(
     def Config(
         default: Union[T, object] = _UNSET_SENTINEL,
         justknob: Optional[str] = None,
-        env_name_default: Optional[Union[str, List[str]]] = None,
-        env_name_force: Optional[Union[str, List[str]]] = None,
+        env_name_default: Optional[str] = None,
+        env_name_force: Optional[str] = None,
         value_type: Optional[type] = None,
         alias: Optional[str] = None,
     ) -> _Config[T]:
@@ -317,15 +300,11 @@ def __init__(self, config: _Config):
         self.justknob = config.justknob
         self.alias = config.alias
         if config.env_name_default is not None:
-            for val in config.env_name_default:
-                if (env_value := _read_env_variable(val)) is not None:
-                    self.env_value_default = env_value
-                    break
+            if (env_value := _read_env_variable(config.env_name_default)) is not None:
+                self.env_value_default = env_value
         if config.env_name_force is not None:
-            for val in config.env_name_force:
-                if (env_value := _read_env_variable(val)) is not None:
-                    self.env_value_force = env_value
-                    break
+            if (env_value := _read_env_variable(config.env_name_force)) is not None:
+                self.env_value_force = env_value
 
 
 class ConfigModule(ModuleType):