From 7a84eebdc3d4733552f8d7a304663d7dfe427590 Mon Sep 17 00:00:00 2001
From: Ignas Anikevicius <240938+aignas@users.noreply.github.com>
Date: Fri, 14 Jun 2024 19:33:06 +0900
Subject: [PATCH 01/12] feat: add runtime_env toolchain suite to replace
 "autodetecting" toolchain

This adds a more comprehensive replacement for the "autodetecting"
toolchain. Specifically, it defines all our toolchain types so that
they take precedence when specified. This prevents the hemertic
toolchains (registered by default) from accidentally being used when
undesired.

To keep the behaviour backwards compatible, an alias is added for the
autodetecting toolchain with a deprecation notice.

Co-Authored-by: Richard Levasseur <richardlev@gmail.com>
---
 CHANGELOG.md                                  |  14 +++
 docs/sphinx/api/python/index.md               |  15 +--
 .../python/runtime_env_toolchains/index.md    |  38 +++++++
 docs/sphinx/toolchains.md                     |   2 +-
 python/BUILD.bazel                            |   9 +-
 python/private/BUILD.bazel                    |  13 ++-
 python/private/autodetecting_toolchain.bzl    |  71 ------------
 python/private/py_cc_toolchain_rule.bzl       |   8 ++
 python/private/py_exec_tools_toolchain.bzl    |  19 +++-
 python/private/py_runtime_pair_rule.bzl       |   9 ++
 python/private/runtime_env_toolchain.bzl      | 107 ++++++++++++++++++
 ...h => runtime_env_toolchain_interpreter.sh} |   4 +-
 python/runtime_env_toolchains/BUILD.bazel     |  19 ++++
 .../precompile/precompile_tests.bzl           |   5 +
 tests/runtime_env_toolchain/BUILD.bazel       |  17 +++
 .../runtime_env_toolchain_tests.bzl           |  92 +++++++++++++++
 16 files changed, 348 insertions(+), 94 deletions(-)
 create mode 100644 docs/sphinx/api/python/runtime_env_toolchains/index.md
 delete mode 100644 python/private/autodetecting_toolchain.bzl
 create mode 100644 python/private/runtime_env_toolchain.bzl
 rename python/private/{autodetecting_toolchain_interpreter.sh => runtime_env_toolchain_interpreter.sh} (94%)
 create mode 100644 python/runtime_env_toolchains/BUILD.bazel
 create mode 100644 tests/runtime_env_toolchain/BUILD.bazel
 create mode 100644 tests/runtime_env_toolchain/runtime_env_toolchain_tests.bzl

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 9dc5ec4bca..e82b6ae635 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -31,6 +31,9 @@ A brief description of the categories of changes:
 * (toolchains) The exec tools toolchain now finds its interpreter by reusing
   the regular interpreter toolchain. This avoids having to duplicate specifying
   where the runtime for the exec tools toolchain is.
+* (toolchains) ({obj}`//python:autodetecting_toolchain`) is deprecated. It is replaced by
+  {obj}`//python/runtime_env_toolchains:all`. The old target will be removed
+  in a future release.
 
 ### Fixed
 * (bzlmod): Targets in `all_requirements` now use the same form as targets returned by the `requirement` macro.
@@ -46,6 +49,17 @@ A brief description of the categories of changes:
   Fixes [#1996](https://github.com/bazelbuild/rules_python/issues/1996).
 * (rules) The first element of the default outputs is now the executable again.
 * (pip) Fixed crash when pypi packages lacked a sha (e.g. yanked packages)
+* The targets would depend on the `exec_tools_toolchain_type` toolchain if it
+  was registered even though the pre-compilation was not enabled. This has been
+  fixed to not be the case anymore. Fixes
+  [#1967](https://github.com/bazelbuild/rules_python/issues/1967). Users
+  wanting to use the `precompile` feature may have to set the config setting to
+  always do the precompilation and per-target pre-compilation is for now
+  disabled.
+
+### Added
+* (toolchains) TODO: doc how to enable the replacement toolchain
+  Fixes [1967](https://github.com/bazelbuild/rules_python/issues/1967).
 
 ### Removed
 * (pip): Removes the `entrypoint` macro that was replaced by `py_console_script_binary` in 0.26.0.
diff --git a/docs/sphinx/api/python/index.md b/docs/sphinx/api/python/index.md
index 494e7b4a02..6c794475ac 100644
--- a/docs/sphinx/api/python/index.md
+++ b/docs/sphinx/api/python/index.md
@@ -26,18 +26,11 @@ provides:
 
 ::::{target} autodetecting_toolchain
 
-A simple toolchain that simply uses `python3` from the runtime environment.
+Legacy toolchain; despite its name, it doesn't autodetect anything.
 
-Note that this toolchain provides no build-time information, which makes it of
-limited utility.
+:::{deprecated} 0.34.0
 
-This is only provided to aid migration off the builtin Bazel toolchain 
-(`@bazel_tools//python:autodetecting_toolchain`), and is largely only applicable
-to WORKSPACE builds.
-
-:::{deprecated} unspecified
-
-Switch to using a hermetic toolchain or manual toolchain configuration instead.
+Use {obj}`@rules_python//python/runtime_env_toolchain:all` instead.
 :::
-
 ::::
+
diff --git a/docs/sphinx/api/python/runtime_env_toolchains/index.md b/docs/sphinx/api/python/runtime_env_toolchains/index.md
new file mode 100644
index 0000000000..ef31f086d7
--- /dev/null
+++ b/docs/sphinx/api/python/runtime_env_toolchains/index.md
@@ -0,0 +1,38 @@
+:::{default-domain} bzl
+:::
+:::{bzl:currentfile} //python/runtime_env_toolchain:BUILD.bazel
+:::
+
+# //python/runtime_env_toolchain
+
+::::{target} all
+
+A set of toolchains that invoke `python3` from the runtime environment.
+
+Note that this toolchain provides no build-time information, which makes it of
+limited utility. This is because the invocation of `python3` is done when a
+program is run, not at build time.
+
+This is only provided to aid migration off the builtin Bazel toolchain 
+(`@bazel_tools//python:autodetecting_toolchain`), and is largely only applicable
+to WORKSPACE builds.
+
+To use this target, register it as a toolchain in WORKSPACE or MODULE.bazel:
+
+:::
+register_toolchains("@rules_python//python/runtime_env_toolchains:all")
+:::
+
+The benefit of this target over the legacy targets is this defines additional
+toolchain types that rules_python needs. This prevents toolchain resolution from
+continuing to search elsewhere (e.g. potentially incurring a download of the
+hermetic runtimes when they won't be used).
+
+:::{deprecated} 0.34.0
+
+Switch to using a hermetic toolchain or manual toolchain configuration instead.
+:::
+
+:::{versionadded} 0.34.0
+:::
+::::
diff --git a/docs/sphinx/toolchains.md b/docs/sphinx/toolchains.md
index 26557cabed..170b76f90c 100644
--- a/docs/sphinx/toolchains.md
+++ b/docs/sphinx/toolchains.md
@@ -240,5 +240,5 @@ automatically registers a higher-priority toolchain; it won't be used unless
 there is a toolchain misconfiguration somewhere.
 
 To aid migration off the Bazel-builtin toolchain, rules_python provides
-{obj}`@rules_python//python:autodetecting_toolchain`. This is an equivalent
+{obj}`@rules_python//python/autodetecting_toolchain:all`. This is an equivalent
 toolchain, but is implemented using rules_python's objects.
diff --git a/python/BUILD.bazel b/python/BUILD.bazel
index 96b2282221..535f4c1c5b 100644
--- a/python/BUILD.bazel
+++ b/python/BUILD.bazel
@@ -24,7 +24,6 @@ that @rules_python//python is only concerned with the core rules.
 """
 
 load("@bazel_skylib//:bzl_library.bzl", "bzl_library")
-load("//python/private:autodetecting_toolchain.bzl", "define_autodetecting_toolchain")
 load(":current_py_toolchain.bzl", "current_py_toolchain")
 
 package(default_visibility = ["//visibility:public"])
@@ -320,11 +319,15 @@ toolchain_type(
 # safe if you know for a fact that your build is completely compatible with the
 # version of the `python` command installed on the target platform.
 
-define_autodetecting_toolchain(name = "autodetecting_toolchain")
+alias(
+    name = "autodetecting_toolchain",
+    actual = "//python/autodetecting_toolchain",
+    deprecation = "Use //python/autodetecting_toolchain:all instead; targets under //docs are internal.",
+)
 
 alias(
     name = "autodetecting_toolchain_nonstrict",
-    actual = ":autodetecting_toolchain",
+    actual = "//python/autodetecting_toolchain",
 )
 
 # ========= Packaging rules =========
diff --git a/python/private/BUILD.bazel b/python/private/BUILD.bazel
index ccc6acdcbf..3620478ca7 100644
--- a/python/private/BUILD.bazel
+++ b/python/private/BUILD.bazel
@@ -13,6 +13,7 @@
 # limitations under the License.
 
 load("@bazel_skylib//:bzl_library.bzl", "bzl_library")
+load("@bazel_skylib//rules:common_settings.bzl", "bool_setting")
 load("//python:py_binary.bzl", "py_binary")
 load("//python:py_library.bzl", "py_library")
 load("//python:versions.bzl", "print_toolchains_checksums")
@@ -58,9 +59,10 @@ bzl_library(
 )
 
 bzl_library(
-    name = "autodetecting_toolchain_bzl",
-    srcs = ["autodetecting_toolchain.bzl"],
+    name = "runtime_env_toolchain_bzl",
+    srcs = ["runtime_env_toolchain.bzl"],
     deps = [
+        ":py_exec_tools_toolchain_bzl",
         ":toolchain_types_bzl",
         "//python:py_runtime_bzl",
         "//python:py_runtime_pair_bzl",
@@ -365,6 +367,13 @@ config_setting(
     },
 )
 
+# This should only be set by analysis tests to expose additional metadata to
+# aid testing, so a setting instead of a flag.
+bool_setting(
+    name = "visible_for_testing",
+    build_setting_default = False,
+)
+
 print_toolchains_checksums(name = "print_toolchains_checksums")
 
 # Used for py_console_script_gen rule
diff --git a/python/private/autodetecting_toolchain.bzl b/python/private/autodetecting_toolchain.bzl
deleted file mode 100644
index 174136e870..0000000000
--- a/python/private/autodetecting_toolchain.bzl
+++ /dev/null
@@ -1,71 +0,0 @@
-# Copyright 2019 The Bazel Authors. All rights reserved.
-#
-# Licensed under the Apache License, Version 2.0 (the "License");
-# you may not use this file except in compliance with the License.
-# You may obtain a copy of the License at
-#
-#    http://www.apache.org/licenses/LICENSE-2.0
-#
-# Unless required by applicable law or agreed to in writing, software
-# distributed under the License is distributed on an "AS IS" BASIS,
-# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-# See the License for the specific language governing permissions and
-# limitations under the License.
-
-"""Definitions related to the Python toolchain."""
-
-load("//python:py_runtime.bzl", "py_runtime")
-load("//python:py_runtime_pair.bzl", "py_runtime_pair")
-load(":toolchain_types.bzl", "TARGET_TOOLCHAIN_TYPE")
-
-def define_autodetecting_toolchain(name):
-    """Defines the autodetecting Python toolchain.
-
-    Args:
-        name: The name of the toolchain to introduce. Must have value
-            "autodetecting_toolchain". This param is present only to make the
-            BUILD file more readable.
-    """
-    if name != "autodetecting_toolchain":
-        fail("Python autodetecting toolchain must be named " +
-             "'autodetecting_toolchain'")
-
-    # buildifier: disable=native-py
-    py_runtime(
-        name = "_autodetecting_py3_runtime",
-        interpreter = "//python/private:autodetecting_toolchain_interpreter.sh",
-        python_version = "PY3",
-        stub_shebang = "#!/usr/bin/env python3",
-        visibility = ["//visibility:private"],
-    )
-
-    # This is a dummy runtime whose interpreter_path triggers the native rule
-    # logic to use the legacy behavior on Windows.
-    # TODO(#7844): Remove this target.
-    # buildifier: disable=native-py
-    py_runtime(
-        name = "_magic_sentinel_runtime",
-        interpreter_path = "/_magic_pyruntime_sentinel_do_not_use",
-        python_version = "PY3",
-        visibility = ["//visibility:private"],
-    )
-
-    py_runtime_pair(
-        name = "_autodetecting_py_runtime_pair",
-        py3_runtime = select({
-            # If we're on windows, inject the sentinel to tell native rule logic
-            # that we attempted to use the autodetecting toolchain and need to
-            # switch back to legacy behavior.
-            # TODO(#7844): Remove this hack.
-            "@platforms//os:windows": ":_magic_sentinel_runtime",
-            "//conditions:default": ":_autodetecting_py3_runtime",
-        }),
-        visibility = ["//visibility:public"],
-    )
-
-    native.toolchain(
-        name = name,
-        toolchain = ":_autodetecting_py_runtime_pair",
-        toolchain_type = TARGET_TOOLCHAIN_TYPE,
-        visibility = ["//visibility:public"],
-    )
diff --git a/python/private/py_cc_toolchain_rule.bzl b/python/private/py_cc_toolchain_rule.bzl
index 5d3debb702..1599415ac7 100644
--- a/python/private/py_cc_toolchain_rule.bzl
+++ b/python/private/py_cc_toolchain_rule.bzl
@@ -18,6 +18,7 @@ NOTE: This is a beta-quality feature. APIs subject to change until
 https://github.com/bazelbuild/rules_python/issues/824 is considered done.
 """
 
+load("@bazel_skylib//rules:common_settings.bzl", "BuildSettingInfo")
 load("@rules_cc//cc:defs.bzl", "CcInfo")
 load(":py_cc_toolchain_info.bzl", "PyCcToolchainInfo")
 
@@ -37,8 +38,12 @@ def _py_cc_toolchain_impl(ctx):
         ),
         python_version = ctx.attr.python_version,
     )
+    extra_kwargs = {}
+    if ctx.attr._visible_for_testing[BuildSettingInfo].value:
+        extra_kwargs["toolchain_label"] = ctx.label
     return [platform_common.ToolchainInfo(
         py_cc_toolchain = py_cc_toolchain,
+        **extra_kwargs
     )]
 
 py_cc_toolchain = rule(
@@ -60,6 +65,9 @@ py_cc_toolchain = rule(
             doc = "The Major.minor Python version, e.g. 3.11",
             mandatory = True,
         ),
+        "_visible_for_testing": attr.label(
+            default = "//python/private:visible_for_testing",
+        ),
     },
     doc = """\
 A toolchain for a Python runtime's C/C++ information (e.g. headers)
diff --git a/python/private/py_exec_tools_toolchain.bzl b/python/private/py_exec_tools_toolchain.bzl
index 5c17b89625..b3d0fb2634 100644
--- a/python/private/py_exec_tools_toolchain.bzl
+++ b/python/private/py_exec_tools_toolchain.bzl
@@ -14,14 +14,22 @@
 
 """Rule that defines a toolchain for build tools."""
 
+load("@bazel_skylib//rules:common_settings.bzl", "BuildSettingInfo")
 load("//python/private:toolchain_types.bzl", "TARGET_TOOLCHAIN_TYPE")
 load(":py_exec_tools_info.bzl", "PyExecToolsInfo")
 
 def _py_exec_tools_toolchain_impl(ctx):
-    return [platform_common.ToolchainInfo(exec_tools = PyExecToolsInfo(
-        exec_interpreter = ctx.attr.exec_interpreter,
-        precompiler = ctx.attr.precompiler,
-    ))]
+    extra_kwargs = {}
+    if ctx.attr._visible_for_testing[BuildSettingInfo].value:
+        extra_kwargs["toolchain_label"] = ctx.label
+
+    return [platform_common.ToolchainInfo(
+        exec_tools = PyExecToolsInfo(
+            exec_interpreter = ctx.attr.exec_interpreter,
+            precompiler = ctx.attr.precompiler,
+        ),
+        **extra_kwargs
+    )]
 
 py_exec_tools_toolchain = rule(
     implementation = _py_exec_tools_toolchain_impl,
@@ -36,6 +44,9 @@ py_exec_tools_toolchain = rule(
             cfg = "exec",
             doc = "See PyExecToolsInfo.precompiler",
         ),
+        "_visible_for_testing": attr.label(
+            default = "//python/private:visible_for_testing",
+        ),
     },
 )
 
diff --git a/python/private/py_runtime_pair_rule.bzl b/python/private/py_runtime_pair_rule.bzl
index 02f9a5ba89..eb91413563 100644
--- a/python/private/py_runtime_pair_rule.bzl
+++ b/python/private/py_runtime_pair_rule.bzl
@@ -14,6 +14,7 @@
 
 """Implementation of py_runtime_pair."""
 
+load("@bazel_skylib//rules:common_settings.bzl", "BuildSettingInfo")
 load("//python:py_runtime_info.bzl", "PyRuntimeInfo")
 load("//python/private:reexports.bzl", "BuiltinPyRuntimeInfo")
 load("//python/private:util.bzl", "IS_BAZEL_7_OR_HIGHER")
@@ -40,9 +41,14 @@ def _py_runtime_pair_impl(ctx):
     #     fail("Using Python 2 is not supported and disabled; see " +
     #          "https://github.com/bazelbuild/bazel/issues/15684")
 
+    extra_kwargs = {}
+    if ctx.attr._visible_for_testing[BuildSettingInfo].value:
+        extra_kwargs["toolchain_label"] = ctx.label
+
     return [platform_common.ToolchainInfo(
         py2_runtime = py2_runtime,
         py3_runtime = py3_runtime,
+        **extra_kwargs
     )]
 
 def _get_py_runtime_info(target):
@@ -85,6 +91,9 @@ The runtime to use for Python 3 targets. Must have `python_version` set to
 `PY3`.
 """,
         ),
+        "_visible_for_testing": attr.label(
+            default = "//python/private:visible_for_testing",
+        ),
     },
     fragments = ["py"],
     doc = """\
diff --git a/python/private/runtime_env_toolchain.bzl b/python/private/runtime_env_toolchain.bzl
new file mode 100644
index 0000000000..d2c0485a63
--- /dev/null
+++ b/python/private/runtime_env_toolchain.bzl
@@ -0,0 +1,107 @@
+# Copyright 2019 The Bazel Authors. All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Definitions related to the Python toolchain."""
+
+load("//python:py_runtime.bzl", "py_runtime")
+load("//python:py_runtime_pair.bzl", "py_runtime_pair")
+load("//python/cc:py_cc_toolchain.bzl", "py_cc_toolchain")
+load(":py_exec_tools_toolchain.bzl", "py_exec_tools_toolchain")
+load(":toolchain_types.bzl", "EXEC_TOOLS_TOOLCHAIN_TYPE", "TARGET_TOOLCHAIN_TYPE")
+
+_IS_EXEC_TOOLCHAIN_ENABLED = Label("//python/config_settings:is_exec_tools_toolchain_enabled")
+
+def define_runtime_env_toolchain(name):
+    """Defines the runtime_env Python toolchain.
+
+    This is a minimal suite of toolchains that provided limited functionality.
+    They're mostly only useful to aid migration off the builtin
+    `@bazel_tools//tools/python:autodetecting_toolchain` toolchain.
+
+    NOTE: This was previously called the "autodetecting" toolchain, but was
+    renamed to better reflect its behavior, since it doesn't autodetect
+    anything.
+
+    Args:
+        name: The name of the toolchain to introduce.
+    """
+
+    # buildifier: disable=native-py
+    py_runtime(
+        name = "_runtime_env_py3_runtime",
+        interpreter = "//python/private:runtime_env_toolchain_interpreter.sh",
+        python_version = "PY3",
+        stub_shebang = "#!/usr/bin/env python3",
+        visibility = ["//visibility:private"],
+    )
+
+    # This is a dummy runtime whose interpreter_path triggers the native rule
+    # logic to use the legacy behavior on Windows.
+    # TODO(#7844): Remove this target.
+    # buildifier: disable=native-py
+    py_runtime(
+        name = "_magic_sentinel_runtime",
+        interpreter_path = "/_magic_pyruntime_sentinel_do_not_use",
+        python_version = "PY3",
+        visibility = ["//visibility:private"],
+    )
+
+    py_runtime_pair(
+        name = "_runtime_env_py_runtime_pair",
+        py3_runtime = select({
+            # If we're on windows, inject the sentinel to tell native rule logic
+            # that we attempted to use the runtime_env toolchain and need to
+            # switch back to legacy behavior.
+            # TODO(#7844): Remove this hack.
+            "@platforms//os:windows": ":_magic_sentinel_runtime",
+            "//conditions:default": ":_runtime_env_py3_runtime",
+        }),
+        visibility = ["//visibility:public"],
+    )
+
+    native.toolchain(
+        name = name,
+        toolchain = ":_runtime_env_py_runtime_pair",
+        toolchain_type = TARGET_TOOLCHAIN_TYPE,
+        visibility = ["//visibility:public"],
+    )
+
+    py_exec_tools_toolchain(
+        name = name + "_exec_impl",
+        precompiler = Label("//tools/precompiler:precompiler"),
+        visibility = ["//visibility:private"],
+    )
+
+    native.cc_library(
+        name = "empty_lib",
+    )
+    py_cc_toolchain(
+        name = name + "_cc_impl",
+        headers = ":empty_lib",
+        libs = ":empty_lib",
+        python_version = "0.0",
+    )
+    native.toolchain(
+        name = name + "_exec",
+        toolchain = name + "_exec_impl",
+        toolchain_type = EXEC_TOOLS_TOOLCHAIN_TYPE,
+        target_settings = [_IS_EXEC_TOOLCHAIN_ENABLED],
+        visibility = ["//visibility:public"],
+    )
+    native.toolchain(
+        name = name + "_cc",
+        toolchain = name + "_cc_impl",
+        toolchain_type = EXEC_TOOLS_TOOLCHAIN_TYPE,
+        visibility = ["//visibility:public"],
+    )
diff --git a/python/private/autodetecting_toolchain_interpreter.sh b/python/private/runtime_env_toolchain_interpreter.sh
similarity index 94%
rename from python/private/autodetecting_toolchain_interpreter.sh
rename to python/private/runtime_env_toolchain_interpreter.sh
index 5c8a10d601..2cb7cc7151 100644
--- a/python/private/autodetecting_toolchain_interpreter.sh
+++ b/python/private/runtime_env_toolchain_interpreter.sh
@@ -8,8 +8,8 @@ set -u
 # We do lose the ability to set -o pipefail.
 
 FAILURE_HEADER="\
-Error occurred while attempting to use the default Python toolchain \
-(@rules_python//python:autodetecting_toolchain)."
+Error occurred while attempting to use the deprecated Python toolchain \
+(@rules_python//python/runtime_env_toolchain:all)."
 
 die() {
   echo "$FAILURE_HEADER" 1>&2
diff --git a/python/runtime_env_toolchains/BUILD.bazel b/python/runtime_env_toolchains/BUILD.bazel
new file mode 100644
index 0000000000..21355ac939
--- /dev/null
+++ b/python/runtime_env_toolchains/BUILD.bazel
@@ -0,0 +1,19 @@
+# Copyright 2024 The Bazel Authors. All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+load("//python/private:runtime_env_toolchain.bzl", "define_runtime_env_toolchain")
+
+package(default_visibility = ["//:__subpackages__"])
+
+define_runtime_env_toolchain(name = "runtime_env_toolchain")
diff --git a/tests/base_rules/precompile/precompile_tests.bzl b/tests/base_rules/precompile/precompile_tests.bzl
index 58bdafe39c..ca4daebbb6 100644
--- a/tests/base_rules/precompile/precompile_tests.bzl
+++ b/tests/base_rules/precompile/precompile_tests.bzl
@@ -63,6 +63,7 @@ def _test_precompile_enabled_setup(name, py_rule, **kwargs):
         config_settings = {
             "//command_line_option:extra_toolchains": _TEST_TOOLCHAINS,
             EXEC_TOOLS_TOOLCHAIN: "enabled",
+            PRECOMPILE: "enabled",
         },
     )
 
@@ -122,6 +123,7 @@ def _test_pyc_only(name):
             "//command_line_option:extra_toolchains": _TEST_TOOLCHAINS,
             ##PRECOMPILE_SOURCE_RETENTION: "omit_source",
             EXEC_TOOLS_TOOLCHAIN: "enabled",
+            PRECOMPILE: "enabled",
         },
         target = name + "_subject",
     )
@@ -165,6 +167,7 @@ def _test_precompile_if_generated(name):
         config_settings = {
             "//command_line_option:extra_toolchains": _TEST_TOOLCHAINS,
             EXEC_TOOLS_TOOLCHAIN: "enabled",
+            PRECOMPILE: "enabled",
         },
     )
 
@@ -208,6 +211,7 @@ def _test_omit_source_if_generated_source(name):
             "//command_line_option:extra_toolchains": _TEST_TOOLCHAINS,
             PRECOMPILE_SOURCE_RETENTION: "omit_if_generated_source",
             EXEC_TOOLS_TOOLCHAIN: "enabled",
+            PRECOMPILE: "enabled",
         },
     )
 
@@ -295,6 +299,7 @@ def _test_precompiler_action(name):
         config_settings = {
             "//command_line_option:extra_toolchains": _TEST_TOOLCHAINS,
             EXEC_TOOLS_TOOLCHAIN: "enabled",
+            PRECOMPILE: "enabled",
         },
     )
 
diff --git a/tests/runtime_env_toolchain/BUILD.bazel b/tests/runtime_env_toolchain/BUILD.bazel
new file mode 100644
index 0000000000..ebcdbaf017
--- /dev/null
+++ b/tests/runtime_env_toolchain/BUILD.bazel
@@ -0,0 +1,17 @@
+# Copyright 2024 The Bazel Authors. All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+load(":runtime_env_toolchain_tests.bzl", "runtime_env_toolchain_test_suite")
+
+runtime_env_toolchain_test_suite(name = "runtime_env_toolchain_tests")
diff --git a/tests/runtime_env_toolchain/runtime_env_toolchain_tests.bzl b/tests/runtime_env_toolchain/runtime_env_toolchain_tests.bzl
new file mode 100644
index 0000000000..c54fe6bcbd
--- /dev/null
+++ b/tests/runtime_env_toolchain/runtime_env_toolchain_tests.bzl
@@ -0,0 +1,92 @@
+# Copyright 2024 The Bazel Authors. All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Starlark tests for py_runtime rule."""
+
+load("@rules_python_internal//:rules_python_config.bzl", "config")
+load("@rules_testing//lib:analysis_test.bzl", "analysis_test")
+load("@rules_testing//lib:test_suite.bzl", "test_suite")
+load("@rules_testing//lib:truth.bzl", "matching")
+load("@rules_testing//lib:util.bzl", rt_util = "util")
+load("//python:py_runtime.bzl", "py_runtime")
+load("//python:py_runtime_info.bzl", "PyRuntimeInfo")
+load(
+    "//python/private:toolchain_types.bzl",
+    "EXEC_TOOLS_TOOLCHAIN_TYPE",
+    "PY_CC_TOOLCHAIN_TYPE",
+    "TARGET_TOOLCHAIN_TYPE",
+)
+load("//tests:py_runtime_info_subject.bzl", "py_runtime_info_subject")
+load("//tests/base_rules:util.bzl", br_util = "util")
+load(
+    "//tests/support:support.bzl",
+    "EXEC_TOOLS_TOOLCHAIN",
+)
+
+_LookupInfo = provider()
+
+def _use_toolchains_impl(ctx):
+    return [
+        _LookupInfo(
+            target = ctx.toolchains[TARGET_TOOLCHAIN_TYPE],
+            exec = ctx.toolchains[EXEC_TOOLS_TOOLCHAIN_TYPE],
+            cc = ctx.toolchains[PY_CC_TOOLCHAIN_TYPE],
+        ),
+    ]
+
+_use_toolchains = rule(
+    implementation = _use_toolchains_impl,
+    toolchains = [
+        TARGET_TOOLCHAIN_TYPE,
+        EXEC_TOOLS_TOOLCHAIN_TYPE,
+        PY_CC_TOOLCHAIN_TYPE,
+    ],
+)
+
+_tests = []
+
+def _test_runtime_env_toolchain_matches(name):
+    rt_util.helper_target(
+        _use_toolchains,
+        name = name + "_subject",
+    )
+    analysis_test(
+        name = name,
+        impl = _test_runtime_env_toolchain_matches_impl,
+        target = name + "_subject",
+        config_settings = {
+            "//command_line_option:extra_toolchains": [
+                str(Label("//python/runtime_env_toolchains:all")),
+            ],
+            EXEC_TOOLS_TOOLCHAIN: "enabled",
+            str(Label("//python/private:visible_for_testing")): True,
+        },
+    )
+
+def _test_runtime_env_toolchain_matches_impl(env, target):
+    #env.expect.that_target(target).py3_runtime
+    meta = env.expect.meta.derive(format_str_kwargs = {"package": target.label.package})
+
+    env.expect.that_str(
+        str(target[_LookupInfo].target.toolchain_label),
+    ).contains("runtime_env_toolchain")
+    env.expect.that_str(
+        str(target[_LookupInfo].exec.toolchain_label),
+    ).contains("runtime_env_toolchain")
+    print(target[_LookupInfo].cc.toolchain_label)
+
+_tests.append(_test_runtime_env_toolchain_matches)
+
+def runtime_env_toolchain_test_suite(name):
+    test_suite(name = name, tests = _tests)

From bddf1c02f46bf2e7c9659eabdf3fc8134c8f8e59 Mon Sep 17 00:00:00 2001
From: Ignas Anikevicius <240938+aignas@users.noreply.github.com>
Date: Thu, 27 Jun 2024 11:10:13 +0900
Subject: [PATCH 02/12] Update python/private/BUILD.bazel

---
 python/private/BUILD.bazel | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/python/private/BUILD.bazel b/python/private/BUILD.bazel
index 3620478ca7..c386b6701e 100644
--- a/python/private/BUILD.bazel
+++ b/python/private/BUILD.bazel
@@ -372,6 +372,8 @@ config_setting(
 bool_setting(
     name = "visible_for_testing",
     build_setting_default = False,
+    # This is only because it is an implicit dependency by the toolchains.
+    visibility = ["//visibility:public"],
 )
 
 print_toolchains_checksums(name = "print_toolchains_checksums")

From 5e1194b1bbac2e411c90d2c21dede0472f5b7dfc Mon Sep 17 00:00:00 2001
From: Richard Levasseur <rlevasseur@google.com>
Date: Wed, 26 Jun 2024 19:30:05 -0700
Subject: [PATCH 03/12] fixup! feat: add runtime_env toolchain suite to replace
 "autodetecting" toolchain

finish doc
---
 CHANGELOG.md | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index e82b6ae635..3497ad10ac 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -58,8 +58,8 @@ A brief description of the categories of changes:
   disabled.
 
 ### Added
-* (toolchains) TODO: doc how to enable the replacement toolchain
-  Fixes [1967](https://github.com/bazelbuild/rules_python/issues/1967).
+* (toolchains) {obj}`//python/runtime_env_toolchains:all`, which is a
+  drop-in replacement for the "autodetecting" toolchain.
 
 ### Removed
 * (pip): Removes the `entrypoint` macro that was replaced by `py_console_script_binary` in 0.26.0.

From 55ec794aad3ef3a57a6e37e830b6f12d66e4e9a0 Mon Sep 17 00:00:00 2001
From: Richard Levasseur <rlevasseur@google.com>
Date: Wed, 26 Jun 2024 22:21:28 -0700
Subject: [PATCH 04/12] fixup

finish rename
add missing deps
fx tests
---
 docs/sphinx/toolchains.md                     |  2 +-
 python/BUILD.bazel                            |  2 +-
 python/private/BUILD.bazel                    |  8 ++++-
 python/private/runtime_env_toolchain.bzl      | 34 ++++++++++---------
 .../runtime_env_toolchain_tests.bzl           | 11 +++---
 5 files changed, 32 insertions(+), 25 deletions(-)

diff --git a/docs/sphinx/toolchains.md b/docs/sphinx/toolchains.md
index 170b76f90c..fac1bfc6b0 100644
--- a/docs/sphinx/toolchains.md
+++ b/docs/sphinx/toolchains.md
@@ -240,5 +240,5 @@ automatically registers a higher-priority toolchain; it won't be used unless
 there is a toolchain misconfiguration somewhere.
 
 To aid migration off the Bazel-builtin toolchain, rules_python provides
-{obj}`@rules_python//python/autodetecting_toolchain:all`. This is an equivalent
+{obj}`@rules_python//python/runtime_env_toolchains:all`. This is an equivalent
 toolchain, but is implemented using rules_python's objects.
diff --git a/python/BUILD.bazel b/python/BUILD.bazel
index 535f4c1c5b..10f4df1242 100644
--- a/python/BUILD.bazel
+++ b/python/BUILD.bazel
@@ -321,7 +321,7 @@ toolchain_type(
 
 alias(
     name = "autodetecting_toolchain",
-    actual = "//python/autodetecting_toolchain",
+    actual = "//python/runtime_env_toolchains:runtime_env_toolchain",
     deprecation = "Use //python/autodetecting_toolchain:all instead; targets under //docs are internal.",
 )
 
diff --git a/python/private/BUILD.bazel b/python/private/BUILD.bazel
index 3620478ca7..e3e2984a24 100644
--- a/python/private/BUILD.bazel
+++ b/python/private/BUILD.bazel
@@ -142,6 +142,7 @@ bzl_library(
         ":py_cc_toolchain_info_bzl",
         ":rules_cc_srcs_bzl",
         ":util_bzl",
+        "@bazel_skylib//rules:common_settings",
     ],
 )
 
@@ -166,7 +167,11 @@ bzl_library(
 bzl_library(
     name = "py_exec_tools_toolchain_bzl",
     srcs = ["py_exec_tools_toolchain.bzl"],
-    deps = ["//python/private/common:providers_bzl"],
+    deps = [
+        ":toolchain_types_bzl",
+        "//python/private/common:providers_bzl",
+        "@bazel_skylib//rules:common_settings",
+    ],
 )
 
 bzl_library(
@@ -194,6 +199,7 @@ bzl_library(
     deps = [
         "//python:py_runtime_bzl",
         "//python:py_runtime_info_bzl",
+        "@bazel_skylib//rules:common_settings",
     ],
 )
 
diff --git a/python/private/runtime_env_toolchain.bzl b/python/private/runtime_env_toolchain.bzl
index d2c0485a63..8991469a4a 100644
--- a/python/private/runtime_env_toolchain.bzl
+++ b/python/private/runtime_env_toolchain.bzl
@@ -18,7 +18,7 @@ load("//python:py_runtime.bzl", "py_runtime")
 load("//python:py_runtime_pair.bzl", "py_runtime_pair")
 load("//python/cc:py_cc_toolchain.bzl", "py_cc_toolchain")
 load(":py_exec_tools_toolchain.bzl", "py_exec_tools_toolchain")
-load(":toolchain_types.bzl", "EXEC_TOOLS_TOOLCHAIN_TYPE", "TARGET_TOOLCHAIN_TYPE")
+load(":toolchain_types.bzl", "EXEC_TOOLS_TOOLCHAIN_TYPE", "PY_CC_TOOLCHAIN_TYPE", "TARGET_TOOLCHAIN_TYPE")
 
 _IS_EXEC_TOOLCHAIN_ENABLED = Label("//python/config_settings:is_exec_tools_toolchain_enabled")
 
@@ -36,6 +36,7 @@ def define_runtime_env_toolchain(name):
     Args:
         name: The name of the toolchain to introduce.
     """
+    base_name = name.replace("_toolchain", "")
 
     # buildifier: disable=native-py
     py_runtime(
@@ -78,30 +79,31 @@ def define_runtime_env_toolchain(name):
     )
 
     py_exec_tools_toolchain(
-        name = name + "_exec_impl",
+        name = "_runtime_env_py_exec_tools_toolchain_impl",
         precompiler = Label("//tools/precompiler:precompiler"),
         visibility = ["//visibility:private"],
     )
+    native.toolchain(
+        name = base_name + "_py_exec_tools_toolchain",
+        toolchain = "_runtime_env_py_exec_tools_toolchain_impl",
+        toolchain_type = EXEC_TOOLS_TOOLCHAIN_TYPE,
+        target_settings = [_IS_EXEC_TOOLCHAIN_ENABLED],
+        visibility = ["//visibility:public"],
+    )
 
     native.cc_library(
-        name = "empty_lib",
+        name = "_empty_cc_lib",
+        visibility = ["//visibility:private"],
     )
     py_cc_toolchain(
-        name = name + "_cc_impl",
-        headers = ":empty_lib",
-        libs = ":empty_lib",
+        name = "_runtime_env_py_cc_toolchain_impl",
+        headers = ":_empty_cc_lib",
+        libs = ":_empty_cc_lib",
         python_version = "0.0",
     )
     native.toolchain(
-        name = name + "_exec",
-        toolchain = name + "_exec_impl",
-        toolchain_type = EXEC_TOOLS_TOOLCHAIN_TYPE,
-        target_settings = [_IS_EXEC_TOOLCHAIN_ENABLED],
-        visibility = ["//visibility:public"],
-    )
-    native.toolchain(
-        name = name + "_cc",
-        toolchain = name + "_cc_impl",
-        toolchain_type = EXEC_TOOLS_TOOLCHAIN_TYPE,
+        name = base_name + "_py_cc_toolchain",
+        toolchain = ":_runtime_env_py_cc_toolchain_impl",
+        toolchain_type = PY_CC_TOOLCHAIN_TYPE,
         visibility = ["//visibility:public"],
     )
diff --git a/tests/runtime_env_toolchain/runtime_env_toolchain_tests.bzl b/tests/runtime_env_toolchain/runtime_env_toolchain_tests.bzl
index c54fe6bcbd..4efb4ef772 100644
--- a/tests/runtime_env_toolchain/runtime_env_toolchain_tests.bzl
+++ b/tests/runtime_env_toolchain/runtime_env_toolchain_tests.bzl
@@ -75,16 +75,15 @@ def _test_runtime_env_toolchain_matches(name):
     )
 
 def _test_runtime_env_toolchain_matches_impl(env, target):
-    #env.expect.that_target(target).py3_runtime
-    meta = env.expect.meta.derive(format_str_kwargs = {"package": target.label.package})
-
     env.expect.that_str(
         str(target[_LookupInfo].target.toolchain_label),
-    ).contains("runtime_env_toolchain")
+    ).contains("runtime_env_py_runtime_pair")
     env.expect.that_str(
         str(target[_LookupInfo].exec.toolchain_label),
-    ).contains("runtime_env_toolchain")
-    print(target[_LookupInfo].cc.toolchain_label)
+    ).contains("runtime_env_py_exec_tools")
+    env.expect.that_str(
+        str(target[_LookupInfo].cc.toolchain_label),
+    ).contains("runtime_env_py_cc")
 
 _tests.append(_test_runtime_env_toolchain_matches)
 

From df3a449284845cb77333f658554992367d03c913 Mon Sep 17 00:00:00 2001
From: Richard Levasseur <rlevasseur@google.com>
Date: Wed, 26 Jun 2024 22:29:28 -0700
Subject: [PATCH 05/12] fixup: buildifier

---
 python/private/runtime_env_toolchain.bzl          |  5 ++---
 .../runtime_env_toolchain_tests.bzl               | 15 +++------------
 2 files changed, 5 insertions(+), 15 deletions(-)

diff --git a/python/private/runtime_env_toolchain.bzl b/python/private/runtime_env_toolchain.bzl
index 8991469a4a..e11cfd5494 100644
--- a/python/private/runtime_env_toolchain.bzl
+++ b/python/private/runtime_env_toolchain.bzl
@@ -11,9 +11,9 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-
 """Definitions related to the Python toolchain."""
 
+load("@rules_cc//cc:defs.bzl", "cc_library")
 load("//python:py_runtime.bzl", "py_runtime")
 load("//python:py_runtime_pair.bzl", "py_runtime_pair")
 load("//python/cc:py_cc_toolchain.bzl", "py_cc_toolchain")
@@ -90,8 +90,7 @@ def define_runtime_env_toolchain(name):
         target_settings = [_IS_EXEC_TOOLCHAIN_ENABLED],
         visibility = ["//visibility:public"],
     )
-
-    native.cc_library(
+    cc_library(
         name = "_empty_cc_lib",
         visibility = ["//visibility:private"],
     )
diff --git a/tests/runtime_env_toolchain/runtime_env_toolchain_tests.bzl b/tests/runtime_env_toolchain/runtime_env_toolchain_tests.bzl
index 4efb4ef772..c678b570fa 100644
--- a/tests/runtime_env_toolchain/runtime_env_toolchain_tests.bzl
+++ b/tests/runtime_env_toolchain/runtime_env_toolchain_tests.bzl
@@ -14,27 +14,18 @@
 
 """Starlark tests for py_runtime rule."""
 
-load("@rules_python_internal//:rules_python_config.bzl", "config")
 load("@rules_testing//lib:analysis_test.bzl", "analysis_test")
 load("@rules_testing//lib:test_suite.bzl", "test_suite")
-load("@rules_testing//lib:truth.bzl", "matching")
 load("@rules_testing//lib:util.bzl", rt_util = "util")
-load("//python:py_runtime.bzl", "py_runtime")
-load("//python:py_runtime_info.bzl", "PyRuntimeInfo")
 load(
     "//python/private:toolchain_types.bzl",
     "EXEC_TOOLS_TOOLCHAIN_TYPE",
     "PY_CC_TOOLCHAIN_TYPE",
     "TARGET_TOOLCHAIN_TYPE",
-)
-load("//tests:py_runtime_info_subject.bzl", "py_runtime_info_subject")
-load("//tests/base_rules:util.bzl", br_util = "util")
-load(
-    "//tests/support:support.bzl",
-    "EXEC_TOOLS_TOOLCHAIN",
-)
+)  # buildifier: disable=bzl-visibility
+load("//tests/support:support.bzl", "EXEC_TOOLS_TOOLCHAIN")
 
-_LookupInfo = provider()
+_LookupInfo = provider()  # buildifier: disable=provider-params
 
 def _use_toolchains_impl(ctx):
     return [

From 7b14c041516e475eee46f3fc0b8478cd3c0e8e63 Mon Sep 17 00:00:00 2001
From: Richard Levasseur <rlevasseur@google.com>
Date: Wed, 26 Jun 2024 22:32:47 -0700
Subject: [PATCH 06/12] fix autodetecting alias

---
 python/BUILD.bazel | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/python/BUILD.bazel b/python/BUILD.bazel
index 10f4df1242..5efa1e5c55 100644
--- a/python/BUILD.bazel
+++ b/python/BUILD.bazel
@@ -322,12 +322,13 @@ toolchain_type(
 alias(
     name = "autodetecting_toolchain",
     actual = "//python/runtime_env_toolchains:runtime_env_toolchain",
-    deprecation = "Use //python/autodetecting_toolchain:all instead; targets under //docs are internal.",
+    deprecation = "Use //python/runtime_env_toolchains:all instead",
 )
 
 alias(
     name = "autodetecting_toolchain_nonstrict",
-    actual = "//python/autodetecting_toolchain",
+    actual = "//python/runtime_env_toolchains:all",
+    deprecation = "Use //python/runtime_env_toolchains:all instead",
 )
 
 # ========= Packaging rules =========

From 4ada95e16b7ec8f98f19681a0eb2fc56e29a4e04 Mon Sep 17 00:00:00 2001
From: Richard Levasseur <rlevasseur@google.com>
Date: Thu, 27 Jun 2024 09:11:46 -0700
Subject: [PATCH 07/12] fix nonstrict alias

---
 python/BUILD.bazel | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/python/BUILD.bazel b/python/BUILD.bazel
index 5efa1e5c55..7a69ac8051 100644
--- a/python/BUILD.bazel
+++ b/python/BUILD.bazel
@@ -327,7 +327,7 @@ alias(
 
 alias(
     name = "autodetecting_toolchain_nonstrict",
-    actual = "//python/runtime_env_toolchains:all",
+    actual = "//python/runtime_env_toolchains:runtime_env_toolchain",
     deprecation = "Use //python/runtime_env_toolchains:all instead",
 )
 

From 686a009d8540db09b8d439852f6b6b6e6b13bfaa Mon Sep 17 00:00:00 2001
From: Richard Levasseur <rlevasseur@google.com>
Date: Thu, 27 Jun 2024 14:40:58 -0700
Subject: [PATCH 08/12] undo accidental edits to precompile test

---
 .bazelci/presubmit.yml                           | 1 +
 tests/base_rules/precompile/precompile_tests.bzl | 4 ----
 2 files changed, 1 insertion(+), 4 deletions(-)

diff --git a/.bazelci/presubmit.yml b/.bazelci/presubmit.yml
index 9fd7cae311..b778ac49a4 100644
--- a/.bazelci/presubmit.yml
+++ b/.bazelci/presubmit.yml
@@ -182,6 +182,7 @@ tasks:
     platform: rbe_ubuntu1604
     test_flags:
       - "--test_tag_filters=-integration-test,-acceptance-test"
+      - "--extra_toolchains=@buildkite_config//config:cc-toolchain"
 
   integration_test_build_file_generation_ubuntu_minimum_supported_workspace:
     <<: *minimum_supported_version
diff --git a/tests/base_rules/precompile/precompile_tests.bzl b/tests/base_rules/precompile/precompile_tests.bzl
index ca4daebbb6..5599f6101f 100644
--- a/tests/base_rules/precompile/precompile_tests.bzl
+++ b/tests/base_rules/precompile/precompile_tests.bzl
@@ -63,7 +63,6 @@ def _test_precompile_enabled_setup(name, py_rule, **kwargs):
         config_settings = {
             "//command_line_option:extra_toolchains": _TEST_TOOLCHAINS,
             EXEC_TOOLS_TOOLCHAIN: "enabled",
-            PRECOMPILE: "enabled",
         },
     )
 
@@ -167,7 +166,6 @@ def _test_precompile_if_generated(name):
         config_settings = {
             "//command_line_option:extra_toolchains": _TEST_TOOLCHAINS,
             EXEC_TOOLS_TOOLCHAIN: "enabled",
-            PRECOMPILE: "enabled",
         },
     )
 
@@ -211,7 +209,6 @@ def _test_omit_source_if_generated_source(name):
             "//command_line_option:extra_toolchains": _TEST_TOOLCHAINS,
             PRECOMPILE_SOURCE_RETENTION: "omit_if_generated_source",
             EXEC_TOOLS_TOOLCHAIN: "enabled",
-            PRECOMPILE: "enabled",
         },
     )
 
@@ -299,7 +296,6 @@ def _test_precompiler_action(name):
         config_settings = {
             "//command_line_option:extra_toolchains": _TEST_TOOLCHAINS,
             EXEC_TOOLS_TOOLCHAIN: "enabled",
-            PRECOMPILE: "enabled",
         },
     )
 

From 00af9943fca867750c8aa1c4be63ca4297f77163 Mon Sep 17 00:00:00 2001
From: Richard Levasseur <rlevasseur@google.com>
Date: Thu, 27 Jun 2024 14:49:12 -0700
Subject: [PATCH 09/12] fix pycc part of runtime_env test

---
 .../runtime_env_toolchain/runtime_env_toolchain_tests.bzl | 8 ++++++--
 tests/support/support.bzl                                 | 1 +
 2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/tests/runtime_env_toolchain/runtime_env_toolchain_tests.bzl b/tests/runtime_env_toolchain/runtime_env_toolchain_tests.bzl
index c678b570fa..bc27ebe3bf 100644
--- a/tests/runtime_env_toolchain/runtime_env_toolchain_tests.bzl
+++ b/tests/runtime_env_toolchain/runtime_env_toolchain_tests.bzl
@@ -23,7 +23,7 @@ load(
     "PY_CC_TOOLCHAIN_TYPE",
     "TARGET_TOOLCHAIN_TYPE",
 )  # buildifier: disable=bzl-visibility
-load("//tests/support:support.bzl", "EXEC_TOOLS_TOOLCHAIN")
+load("//tests/support:support.bzl", "CC_TOOLCHAIN", "EXEC_TOOLS_TOOLCHAIN", "VISIBLE_FOR_TESTING")
 
 _LookupInfo = provider()  # buildifier: disable=provider-params
 
@@ -58,10 +58,14 @@ def _test_runtime_env_toolchain_matches(name):
         target = name + "_subject",
         config_settings = {
             "//command_line_option:extra_toolchains": [
+                # NOTE: CC_TOOLCHAIN also defines a py cc toolchain, so it must
+                # come before the runtime_env_toolchains in this list so that
+                # the runtime_env one takes precedence.
+                CC_TOOLCHAIN,
                 str(Label("//python/runtime_env_toolchains:all")),
             ],
             EXEC_TOOLS_TOOLCHAIN: "enabled",
-            str(Label("//python/private:visible_for_testing")): True,
+            VISIBLE_FOR_TESTING: True,
         },
     )
 
diff --git a/tests/support/support.bzl b/tests/support/support.bzl
index 2e5820312a..a74346d7b3 100644
--- a/tests/support/support.bzl
+++ b/tests/support/support.bzl
@@ -37,3 +37,4 @@ PRECOMPILE_ADD_TO_RUNFILES = str(Label("//python/config_settings:precompile_add_
 PRECOMPILE_SOURCE_RETENTION = str(Label("//python/config_settings:precompile_source_retention"))
 PYC_COLLECTION = str(Label("//python/config_settings:pyc_collection"))
 PYTHON_VERSION = str(Label("//python/config_settings:python_version"))
+VISIBLE_FOR_TESTING = str(Label("//python/private:visible_for_testing"))

From 9e73e87c069328483da81a632c1091bfa842a920 Mon Sep 17 00:00:00 2001
From: Richard Levasseur <rlevasseur@google.com>
Date: Thu, 27 Jun 2024 18:53:35 -0700
Subject: [PATCH 10/12] fix toolchain ordering in test

---
 python/private/runtime_env_toolchain.bzl      |  8 +++--
 .../runtime_env_toolchain_tests.bzl           | 29 ++++++++++++++-----
 2 files changed, 28 insertions(+), 9 deletions(-)

diff --git a/python/private/runtime_env_toolchain.bzl b/python/private/runtime_env_toolchain.bzl
index e11cfd5494..1601926178 100644
--- a/python/private/runtime_env_toolchain.bzl
+++ b/python/private/runtime_env_toolchain.bzl
@@ -38,24 +38,24 @@ def define_runtime_env_toolchain(name):
     """
     base_name = name.replace("_toolchain", "")
 
-    # buildifier: disable=native-py
     py_runtime(
         name = "_runtime_env_py3_runtime",
         interpreter = "//python/private:runtime_env_toolchain_interpreter.sh",
         python_version = "PY3",
         stub_shebang = "#!/usr/bin/env python3",
         visibility = ["//visibility:private"],
+        tags = ["manual"],
     )
 
     # This is a dummy runtime whose interpreter_path triggers the native rule
     # logic to use the legacy behavior on Windows.
     # TODO(#7844): Remove this target.
-    # buildifier: disable=native-py
     py_runtime(
         name = "_magic_sentinel_runtime",
         interpreter_path = "/_magic_pyruntime_sentinel_do_not_use",
         python_version = "PY3",
         visibility = ["//visibility:private"],
+        tags = ["manual"],
     )
 
     py_runtime_pair(
@@ -69,6 +69,7 @@ def define_runtime_env_toolchain(name):
             "//conditions:default": ":_runtime_env_py3_runtime",
         }),
         visibility = ["//visibility:public"],
+        tags = ["manual"],
     )
 
     native.toolchain(
@@ -82,6 +83,7 @@ def define_runtime_env_toolchain(name):
         name = "_runtime_env_py_exec_tools_toolchain_impl",
         precompiler = Label("//tools/precompiler:precompiler"),
         visibility = ["//visibility:private"],
+        tags = ["manual"],
     )
     native.toolchain(
         name = base_name + "_py_exec_tools_toolchain",
@@ -93,12 +95,14 @@ def define_runtime_env_toolchain(name):
     cc_library(
         name = "_empty_cc_lib",
         visibility = ["//visibility:private"],
+        tags = ["manual"],
     )
     py_cc_toolchain(
         name = "_runtime_env_py_cc_toolchain_impl",
         headers = ":_empty_cc_lib",
         libs = ":_empty_cc_lib",
         python_version = "0.0",
+        tags = ["manual"],
     )
     native.toolchain(
         name = base_name + "_py_cc_toolchain",
diff --git a/tests/runtime_env_toolchain/runtime_env_toolchain_tests.bzl b/tests/runtime_env_toolchain/runtime_env_toolchain_tests.bzl
index bc27ebe3bf..56faaa11a9 100644
--- a/tests/runtime_env_toolchain/runtime_env_toolchain_tests.bzl
+++ b/tests/runtime_env_toolchain/runtime_env_toolchain_tests.bzl
@@ -23,6 +23,7 @@ load(
     "PY_CC_TOOLCHAIN_TYPE",
     "TARGET_TOOLCHAIN_TYPE",
 )  # buildifier: disable=bzl-visibility
+load("//python/private:util.bzl", "IS_BAZEL_7_OR_HIGHER")
 load("//tests/support:support.bzl", "CC_TOOLCHAIN", "EXEC_TOOLS_TOOLCHAIN", "VISIBLE_FOR_TESTING")
 
 _LookupInfo = provider()  # buildifier: disable=provider-params
@@ -52,18 +53,32 @@ def _test_runtime_env_toolchain_matches(name):
         _use_toolchains,
         name = name + "_subject",
     )
+    extra_toolchains = [
+        str(Label("//python/runtime_env_toolchains:all")),
+    ]
+
+    # We have to add a cc toolchain because py_cc toolchain depends on it.
+    # However, that package also defines a different fake py_cc toolchain we
+    # don't want to use, so we need to ensure the runtime_env toolchain has
+    # higher precendence.
+    # However, Bazel 6 and Bazel 7 process --extra_toolchains in different
+    # orders:
+    #  * Bazel 6 goes left to right
+    #  * Bazel 7 goes right to left
+    # We could just put our preferred toolchain before *and* after
+    # the undesired toolchain...
+    # However, Bazel 7 has a bug where *duplicate* entries are ignored,
+    # and only the *first* entry is respected.
+    if IS_BAZEL_7_OR_HIGHER:
+        extra_toolchains.insert(0, CC_TOOLCHAIN)
+    else:
+        extra_toolchains.append(CC_TOOLCHAIN)
     analysis_test(
         name = name,
         impl = _test_runtime_env_toolchain_matches_impl,
         target = name + "_subject",
         config_settings = {
-            "//command_line_option:extra_toolchains": [
-                # NOTE: CC_TOOLCHAIN also defines a py cc toolchain, so it must
-                # come before the runtime_env_toolchains in this list so that
-                # the runtime_env one takes precedence.
-                CC_TOOLCHAIN,
-                str(Label("//python/runtime_env_toolchains:all")),
-            ],
+            "//command_line_option:extra_toolchains": extra_toolchains,
             EXEC_TOOLS_TOOLCHAIN: "enabled",
             VISIBLE_FOR_TESTING: True,
         },

From 5fdd45c6c07d1a8415fb719d1d5b0060e7d67a99 Mon Sep 17 00:00:00 2001
From: Richard Levasseur <rlevasseur@google.com>
Date: Thu, 27 Jun 2024 18:57:37 -0700
Subject: [PATCH 11/12] fix buildifier

---
 tests/runtime_env_toolchain/runtime_env_toolchain_tests.bzl | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tests/runtime_env_toolchain/runtime_env_toolchain_tests.bzl b/tests/runtime_env_toolchain/runtime_env_toolchain_tests.bzl
index 56faaa11a9..9885a1ef9b 100644
--- a/tests/runtime_env_toolchain/runtime_env_toolchain_tests.bzl
+++ b/tests/runtime_env_toolchain/runtime_env_toolchain_tests.bzl
@@ -23,7 +23,7 @@ load(
     "PY_CC_TOOLCHAIN_TYPE",
     "TARGET_TOOLCHAIN_TYPE",
 )  # buildifier: disable=bzl-visibility
-load("//python/private:util.bzl", "IS_BAZEL_7_OR_HIGHER")
+load("//python/private:util.bzl", "IS_BAZEL_7_OR_HIGHER")  # buildifier: disable=bzl-visibility
 load("//tests/support:support.bzl", "CC_TOOLCHAIN", "EXEC_TOOLS_TOOLCHAIN", "VISIBLE_FOR_TESTING")
 
 _LookupInfo = provider()  # buildifier: disable=provider-params

From 14d7dd3321efa0c73b4c34b25340d837430c9f6d Mon Sep 17 00:00:00 2001
From: Richard Levasseur <rlevasseur@google.com>
Date: Thu, 27 Jun 2024 19:24:59 -0700
Subject: [PATCH 12/12] remove bogus text from changelog

---
 CHANGELOG.md | 17 +++++------------
 1 file changed, 5 insertions(+), 12 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 3497ad10ac..1fe53e70d1 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -31,9 +31,9 @@ A brief description of the categories of changes:
 * (toolchains) The exec tools toolchain now finds its interpreter by reusing
   the regular interpreter toolchain. This avoids having to duplicate specifying
   where the runtime for the exec tools toolchain is.
-* (toolchains) ({obj}`//python:autodetecting_toolchain`) is deprecated. It is replaced by
-  {obj}`//python/runtime_env_toolchains:all`. The old target will be removed
-  in a future release.
+* (toolchains) ({obj}`//python:autodetecting_toolchain`) is deprecated. It is
+  replaced by {obj}`//python/runtime_env_toolchains:all`. The old target will be
+  removed in a future release.
 
 ### Fixed
 * (bzlmod): Targets in `all_requirements` now use the same form as targets returned by the `requirement` macro.
@@ -49,17 +49,10 @@ A brief description of the categories of changes:
   Fixes [#1996](https://github.com/bazelbuild/rules_python/issues/1996).
 * (rules) The first element of the default outputs is now the executable again.
 * (pip) Fixed crash when pypi packages lacked a sha (e.g. yanked packages)
-* The targets would depend on the `exec_tools_toolchain_type` toolchain if it
-  was registered even though the pre-compilation was not enabled. This has been
-  fixed to not be the case anymore. Fixes
-  [#1967](https://github.com/bazelbuild/rules_python/issues/1967). Users
-  wanting to use the `precompile` feature may have to set the config setting to
-  always do the precompilation and per-target pre-compilation is for now
-  disabled.
 
 ### Added
-* (toolchains) {obj}`//python/runtime_env_toolchains:all`, which is a
-  drop-in replacement for the "autodetecting" toolchain.
+* (toolchains) {obj}`//python/runtime_env_toolchains:all`, which is a drop-in
+  replacement for the "autodetecting" toolchain.
 
 ### Removed
 * (pip): Removes the `entrypoint` macro that was replaced by `py_console_script_binary` in 0.26.0.