Squash with environment removal.

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

pants.toml

@@ -136,6 +136,12 @@ pytest_plugins.add = [
 ]
 timeout_default = 60
 
+[test]
+# TODO: These are exposed to tests in order to allow for python interpreter discovery when
+# Pants-tests-Pants: in particular, the [python-setup] subsystem consumes them.
+#   see https://github.com/pantsbuild/pants/issues/11638
+extra_env_vars = ["PYENV_ROOT", "HOME", "PATH"]
+
 [coverage-py]
 interpreter_constraints = [">=3.7,<3.9"]
 

src/python/pants/backend/python/util_rules/pex_cli_test.py

@@ -28,7 +28,9 @@ def test_custom_ca_certs(rule_runner: RuleRunner) -> None:
     with temporary_dir() as tmpdir:
         certs_file = Path(tmpdir) / "certsfile"
         certs_file.write_text("Some fake cert")
-        rule_runner.set_options([f"--ca-certs-path={certs_file}"])
+        rule_runner.set_options(
+            [f"--ca-certs-path={certs_file}"], env={"PATH": None, "PYENV_ROOT": None, "HOME": None}
+        )
         proc = rule_runner.request(
             Process,
             [PexCliProcess(argv=["some", "--args"], description="")],

src/python/pants/backend/python/util_rules/pex_test.py

@@ -351,6 +351,7 @@ def create_pex_and_get_all_data(
         additional_inputs=additional_inputs,
         additional_args=additional_pex_args,
     )
+    env = {**{"PATH": None, "PYENV_ROOT": None, "HOME": None}, **(env or {})}
     rule_runner.set_options(
         ["--backend-packages=pants.backend.python", *additional_pants_args], env=env
     )
@@ -468,6 +469,7 @@ def test_pex_environment(rule_runner: RuleRunner, pex_type: type[Pex | VenvPex])
             "--subprocess-environment-env-vars=LANG",  # Value should come from environment.
             "--subprocess-environment-env-vars=ftp_proxy=dummyproxy",
         ),
+        interpreter_constraints=PexInterpreterConstraints(["CPython>=3.6"]),
         env={"LANG": "es_PY.UTF-8"},
     )
 

src/python/pants/option/global_options_test.py

@@ -10,6 +10,7 @@
 import pytest
 
 from pants.base.build_environment import get_buildroot
+from pants.core.util_rules.pants_environment import PantsEnvironment
 from pants.init.options_initializer import OptionsInitializer
 from pants.option.errors import OptionsError
 from pants.option.global_options import ExecutionOptions, GlobalOptions
@@ -39,7 +40,10 @@ def create_execution_options(
     if plugin:
         args.append(f"--remote-auth-plugin={plugin}")
     ob = create_options_bootstrapper(args)
-    _build_config, options = OptionsInitializer(ob).build_config_and_options(ob, raise_=False)
+    pants_env = PantsEnvironment({})
+    _build_config, options = OptionsInitializer(ob).build_config_and_options(
+        ob, pants_env, raise_=False
+    )
     return ExecutionOptions.from_options(options)
 
 

src/python/pants/python/python_setup.py

@@ -1,6 +1,8 @@
 # Copyright 2014 Pants project contributors (see CONTRIBUTORS.md).
 # Licensed under the Apache License, Version 2.0 (see LICENSE).
 
+from __future__ import annotations
+
 import logging
 import multiprocessing
 import os
@@ -278,6 +280,9 @@ def get_pyenv_paths(pants_env: PantsEnvironment, *, pyenv_local: bool = False) -
                                  '.python-version' file under `build_root`.
         """
         pyenv_root = get_pyenv_root(pants_env)
+        if not pyenv_root:
+            return []
+
         versions_dir = Path(pyenv_root, "versions")
         if not versions_dir.is_dir():
             return []
@@ -305,14 +310,12 @@ def get_pyenv_paths(pants_env: PantsEnvironment, *, pyenv_local: bool = False) -
         return paths
 
 
-def get_pyenv_root(pants_env: PantsEnvironment) -> str:
+def get_pyenv_root(pants_env: PantsEnvironment) -> str | None:
     """See https://github.com/pyenv/pyenv#environment-variables."""
     from_env = pants_env.env.get("PYENV_ROOT")
     if from_env:
         return from_env
     home_from_env = pants_env.env.get("HOME")
     if home_from_env:
         return os.path.join(home_from_env, ".cache")
-    raise ValueError(
-        f"The environment {pants_env} does not contain enough information to locate pyenv."
-    )
+    return None

src/python/pants/python/python_setup_test.py

@@ -72,8 +72,7 @@ def test_get_pyenv_root() -> None:
 
     assert explicit_root == get_pyenv_root(PantsEnvironment({"PYENV_ROOT": explicit_root}))
     assert default_root == get_pyenv_root(PantsEnvironment({"HOME": home}))
-    with pytest.raises(ValueError):
-        assert get_pyenv_root(PantsEnvironment({}))
+    assert get_pyenv_root(PantsEnvironment({})) is None
 
 
 def test_get_pyenv_paths(rule_runner: RuleRunner) -> None:

src/python/pants/testutil/rule_runner.py

@@ -117,6 +117,7 @@ def __init__(
         build_config_builder.register_target_types(target_types or ())
         self.build_config = build_config_builder.create()
 
+        self.pants_environment = PantsEnvironment({})
         self.options_bootstrapper = create_options_bootstrapper()
         options = self.options_bootstrapper.full_options(self.build_config)
         global_options = self.options_bootstrapper.bootstrap_options.for_global_scope()
@@ -148,7 +149,7 @@ def __init__(
             session_values=SessionValues(
                 {
                     OptionsBootstrapper: self.options_bootstrapper,
-                    PantsEnvironment: PantsEnvironment(),
+                    PantsEnvironment: self.pants_environment,
                 }
             ),
         )
@@ -216,23 +217,28 @@ def run_goal_rule(
         console.flush()
         return GoalRuleResult(exit_code, stdout.getvalue(), stderr.getvalue())
 
-    def set_options(self, args: Iterable[str], *, env: Mapping[str, str] | None = None) -> None:
+    def set_options(
+        self, args: Iterable[str], *, env: Mapping[str, str | None] | None = None
+    ) -> None:
         """Update the engine session with new options and/or environment variables.
 
         The environment variables will be used to set the `PantsEnvironment`, which is the
         environment variables captured by the parent Pants process. Some rules use this to be able
         to read arbitrary env vars. Any options that start with `PANTS_` will also be used to set
-        options.
+        options. Giving an environment variable a value of `None` will cause it to be propagated from
+        the test runner's environment (os.environ).
 
         This will override any previously configured values.
         """
+        env = {k: (v if v is not None else os.getenv(k, "")) for k, v in env.items()} if env else {}
         self.options_bootstrapper = create_options_bootstrapper(args=args, env=env)
+        self.pants_environment = PantsEnvironment(env)
         self.scheduler = self.scheduler.scheduler.new_session(
             build_id="buildid_for_test",
             session_values=SessionValues(
                 {
                     OptionsBootstrapper: self.options_bootstrapper,
-                    PantsEnvironment: PantsEnvironment(env),
+                    PantsEnvironment: self.pants_environment,
                 }
             ),
         )

tests/python/pants_test/init/test_plugin_resolver.py

@@ -56,7 +56,10 @@ def rule_runner() -> RuleRunner:
 
 
 def _create_pex(rule_runner: RuleRunner) -> Pex:
-    rule_runner.set_options(["--backend-packages=pants.backend.python"])
+    rule_runner.set_options(
+        ["--backend-packages=pants.backend.python"],
+        env={"PATH": None, "PYENV_ROOT": None, "HOME": None},
+    )
     request = PexRequest(
         output_filename="setup-py-runner.pex",
         internal_only=True,
@@ -157,7 +160,9 @@ def provide_chroot(existing):
             bootstrap_scheduler, interpreter_constraints=interpreter_constraints
         )
         cache_dir = options_bootstrapper.bootstrap_options.for_global_scope().named_caches_dir
-        pants_env = PantsEnvironment(env)
+        pants_env = PantsEnvironment(
+            {**{k: os.getenv(k, "") for k in ["PATH", "HOME", "PYENV_ROOT"]}, **env}
+        )
 
         working_set = plugin_resolver.resolve(
             options_bootstrapper, pants_env, WorkingSet(entries=[])

tests/python/pants_test/pantsd/test_pants_daemon_core.py

@@ -1,6 +1,7 @@
 # Copyright 2020 Pants project contributors (see CONTRIBUTORS.md).
 # Licensed under the Apache License, Version 2.0 (see LICENSE).
 
+from pants.core.util_rules.pants_environment import PantsEnvironment
 from pants.engine.internals.native_engine import PyExecutor
 from pants.pantsd.pants_daemon_core import PantsDaemonCore
 from pants.pantsd.service.pants_service import PantsServices
@@ -13,12 +14,15 @@ def create_services(bootstrap_options, legacy_graph_scheduler):
         return PantsServices()
 
     core = PantsDaemonCore(create_options_bootstrapper([]), PyExecutor(2, 4), create_services)
+    pants_env = PantsEnvironment({})
 
     first_scheduler, first_options_initializer = core.prepare(
-        create_options_bootstrapper(["-ldebug"])
+        create_options_bootstrapper(["-ldebug"]),
+        pants_env,
     )
     second_scheduler, second_options_initializer = core.prepare(
-        create_options_bootstrapper(["-lwarn"])
+        create_options_bootstrapper(["-lwarn"]),
+        pants_env,
     )
     assert first_scheduler is not second_scheduler
     assert first_options_initializer is second_options_initializer