Create no-op builtins stubs for py_runtime, PyRuntimeInfo, and PyInfo

Subsequent changes will begin adding actual functionality. This just creates
stubs than lets the `--experimental_builtins_bzl_path` and
`--experimental_builtins_injection_override` flags allow working with the
builtins code.

Work towards bazelbuild#15897

PiperOrigin-RevId: 483066291
Change-Id: If297913ddbef3e32aada41e7d319c87213921f9d

src/main/starlark/builtins_bzl/common/exports.bzl

@@ -25,6 +25,8 @@ load("@_builtins//:common/objc/linking_support.bzl", "linking_support")
 load("@_builtins//:common/proto/proto_common.bzl", "proto_common_do_not_use")
 load("@_builtins//:common/proto/proto_library.bzl", "proto_library")
 load("@_builtins//:common/proto/proto_lang_toolchain_wrapper.bzl", "proto_lang_toolchain")
+load("@_builtins//:common/python/py_runtime_macro.bzl", "py_runtime")
+load("@_builtins//:common/python/providers.bzl", "PyInfo", "PyRuntimeInfo")
 load("@_builtins//:common/java/proto/java_lite_proto_library.bzl", "java_lite_proto_library")
 load("@_builtins//:common/cc/cc_library.bzl", "cc_library")
 
@@ -35,6 +37,8 @@ exported_toplevels = {
     "_builtins_dummy": "overridden value",
     "CcSharedLibraryInfo": CcSharedLibraryInfo,
     "proto_common_do_not_use": proto_common_do_not_use,
+    "-PyRuntimeInfo": PyRuntimeInfo,
+    "-PyInfo": PyInfo,
 }
 
 # A list of Starlarkified native rules.
@@ -55,6 +59,7 @@ exported_rules = {
     "+cc_test": cc_test,
     "+cc_library": cc_library,
     "proto_lang_toolchain": proto_lang_toolchain,
+    "-py_runtime": py_runtime,
 }
 
 # A list of Starlark functions callable from native rules implementation.

src/main/starlark/builtins_bzl/common/python/providers.bzl

@@ -0,0 +1,16 @@
+# Copyright 2022 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.
+"""Providers for Python rules."""
+PyRuntimeInfo = _builtins.toplevel.PyRuntimeInfo
+PyInfo = _builtins.toplevel.PyInfo

src/main/starlark/builtins_bzl/common/python/py_runtime_macro.bzl

@@ -0,0 +1,22 @@
+# Copyright 2022 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.
+"""Macro to wrap the py_runtime rule."""
+
+load(":common/python/py_runtime_rule.bzl", py_runtime_rule = "py_runtime")
+
+# NOTE: The function name is purposefully selected to match the underlying
+# rule name so that e.g. 'generator_function' shows as the same name so
+# that it is less confusing to users.
+def py_runtime(**kwargs):
+    py_runtime_rule(**kwargs)

src/main/starlark/builtins_bzl/common/python/py_runtime_rule.bzl

@@ -0,0 +1,18 @@
+# Copyright 2022 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.
+"""Implementation of py_runtime rule."""
+
+# Bind to the name "py_runtime" to preserve the kind/rule_class it shows up
+# as elsewhere.
+py_runtime = _builtins.native.py_runtime