Simplifies the class hierarchy so all EnvironmentAwares can define …

…envvars

# Rust tests and lints will be skipped. Delete if not intended.
[ci skip-rust]

# Building wheels and fs_util will be skipped. Delete if not intended.
[ci skip-build-wheels]

src/python/pants/backend/python/subsystems/python_native_code.py

@@ -6,7 +6,7 @@
 from typing import Sequence
 
 from pants.option.option_types import StrListOption
-from pants.option.subsystem import DependsOnEnvVars, Subsystem
+from pants.option.subsystem import Subsystem
 from pants.util.strutil import safe_shlex_join, safe_shlex_split
 
 
@@ -15,8 +15,8 @@ class PythonNativeCodeSubsystem(Subsystem):
     options_scope = "python-native-code"
     help = "Options for building native code using Python, e.g. when resolving distributions."
 
-    class EnvironmentAware(DependsOnEnvVars):
-        env_var_names = ("CPPFLAGS", "LDFLAGS")
+    class EnvironmentAware(Subsystem.EnvironmentAware):
+        depends_on_env_vars = ("CPPFLAGS", "LDFLAGS")
 
         # TODO(#7735): move the --cpp-flags and --ld-flags to a general subprocess support subsystem.
         _cpp_flags = StrListOption(

src/python/pants/backend/shell/shell_setup.py

@@ -6,7 +6,7 @@
 import os
 
 from pants.option.option_types import BoolOption, StrListOption
-from pants.option.subsystem import DependsOnEnvVars, Subsystem
+from pants.option.subsystem import Subsystem
 from pants.util.memo import memoized_property
 from pants.util.ordered_set import OrderedSet
 from pants.util.strutil import softwrap
@@ -31,8 +31,8 @@ class ShellSetup(Subsystem):
         advanced=True,
     )
 
-    class EnvironmentAware(DependsOnEnvVars):
-        env_var_names = ("PATH",)
+    class EnvironmentAware(Subsystem.EnvironmentAware):
+        depends_on_env_vars = ("PATH",)
 
         _executable_search_path = StrListOption(
             default=["<PATH>"],

src/python/pants/option/subsystem.py

@@ -88,8 +88,11 @@ class EnvironmentAware(metaclass=ABCMeta):
         """
 
         subsystem: ClassVar[type[Subsystem]]
+        depends_on_env_vars: ClassVar[tuple[str, ...]] = ()
+
         options: OptionValueContainer
         env_tgt: EnvironmentTarget
+        env_vars: EnvironmentVars
 
         def __getattribute__(self, __name: str) -> Any:
             from pants.core.util_rules.environments import resolve_environment_sensitive_option
@@ -255,14 +258,6 @@ def __eq__(self, other: Any) -> bool:
         return bool(self.options == other.options)
 
 
-class DependsOnEnvVars:
-    """Indicates that an `EnvironmentAware` subclass depends environment variables, and makes them
-    available to instances at construction time."""
-
-    env_var_names: ClassVar[tuple[str, ...]]
-    env_vars: EnvironmentVars
-
-
 async def _construct_subsytem(subsystem_typ: type[_SubsystemT]) -> _SubsystemT:
     scoped_options = await Get(ScopedOptions, Scope(str(subsystem_typ.options_scope)))
     return subsystem_typ(scoped_options.options)
@@ -281,7 +276,7 @@ async def _construct_env_aware(
     t.options = subsystem_instance.options
     t.env_tgt = env_tgt
 
-    if isinstance(t, DependsOnEnvVars):
-        t.env_vars = await Get(EnvironmentVars, EnvironmentVarsRequest(t.env_var_names))
+    if t.depends_on_env_vars:
+        t.env_vars = await Get(EnvironmentVars, EnvironmentVarsRequest(t.depends_on_env_vars))
 
     return t