1 files changed, 58 insertions, 0 deletions
diff --git a/python/current_py_toolchain.bzl b/python/current_py_toolchain.bzl
new file mode 100644
index 0000000..e3345cb
--- /dev/null
+++ b/python/current_py_toolchain.bzl
@@ -0,0 +1,58 @@
+# Copyright 2023 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.
+
+"""Public entry point for current_py_toolchain rule."""
+
+def _current_py_toolchain_impl(ctx):
+    toolchain = ctx.toolchains[ctx.attr._toolchain]
+
+    direct = []
+    transitive = []
+    vars = {}
+
+    if toolchain.py3_runtime and toolchain.py3_runtime.interpreter:
+        direct.append(toolchain.py3_runtime.interpreter)
+        transitive.append(toolchain.py3_runtime.files)
+        vars["PYTHON3"] = toolchain.py3_runtime.interpreter.path
+
+    if toolchain.py2_runtime and toolchain.py2_runtime.interpreter:
+        direct.append(toolchain.py2_runtime.interpreter)
+        transitive.append(toolchain.py2_runtime.files)
+        vars["PYTHON2"] = toolchain.py2_runtime.interpreter.path
+
+    files = depset(direct, transitive = transitive)
+    return [
+        toolchain,
+        platform_common.TemplateVariableInfo(vars),
+        DefaultInfo(
+            runfiles = ctx.runfiles(transitive_files = files),
+            files = files,
+        ),
+    ]
+
+current_py_toolchain = rule(
+    doc = """
+    This rule exists so that the current python toolchain can be used in the `toolchains` attribute of
+    other rules, such as genrule. It allows exposing a python toolchain after toolchain resolution has
+    happened, to a rule which expects a concrete implementation of a toolchain, rather than a
+    toolchain_type which could be resolved to that toolchain.
+    """,
+    implementation = _current_py_toolchain_impl,
+    attrs = {
+        "_toolchain": attr.string(default = str(Label("@bazel_tools//tools/python:toolchain_type"))),
+    },
+    toolchains = [
+        str(Label("@bazel_tools//tools/python:toolchain_type")),
+    ],
+)