chore: fix python test by using normal pip.parse

I'd rather have rules_py just unpack a wheel, but it's broken

MODULE.bazel

@@ -11,7 +11,10 @@ bazel_dep(name = "rules_proto", version = "6.0.0-rc2")
 bazel_dep(name = "platforms", version = "0.0.8")
 
 protoc = use_extension("//protoc:extensions.bzl", "protoc")
-protoc.toolchain(google_protobuf = "com_google_protobuf", version = "v25.3")
+protoc.toolchain(
+    google_protobuf = "com_google_protobuf",
+    version = "v25.3",
+)
 use_repo(protoc, "com_google_protobuf", "toolchains_protoc_hub")
 
 register_toolchains("@toolchains_protoc_hub//:all")
@@ -22,7 +25,7 @@ bazel_dep(name = "aspect_rules_py", version = "0.7.1", dev_dependency = True)
 bazel_dep(name = "rules_java", version = "7.4.0", dev_dependency = True)
 bazel_dep(name = "rules_python", version = "0.31.0", dev_dependency = True)
 
-# Update to include
+# # Update to include
 # https://github.com/bazelbuild/rules_python/pull/1577
 git_override(
     module_name = "rules_python",
@@ -34,3 +37,12 @@ register_toolchains(
     "//examples/lang_toolchains:all",
     dev_dependency = True,
 )
+
+# Shows how a typical Python user fetches all the dependencies of their app, including the protobuf runtime
+pip = use_extension("@rules_python//python/extensions:pip.bzl", "pip")
+pip.parse(
+    hub_name = "pypi",
+    python_version = "3.11",
+    requirements_lock = "//examples/lang_toolchains:requirements.txt",
+)
+use_repo(pip, "pypi")

WORKSPACE.bazel

@@ -1,17 +1,9 @@
 # Marker that this is the root of a Bazel workspace.
 
-load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_file", "http_jar")
-
-# Fetch the runtime package that applications need to marshal proto files.
-# This does NOT do any code generation of .pb2.py files, we still use protoc for that.
-# From https://pypi.org/project/protobuf/4.25.3/
-http_file(
-    name = "protobuf_4_25_3",
-    downloaded_file_path = "protobuf-4.25.3-py3-none-any.whl",
-    sha256 = "f0700d54bcf45424477e46a9f0944155b46fb0639d69728739c0e47bab83f2b9",
-    urls = ["https://files.pythonhosted.org/packages/f4/d5/db585a5e8d64af6b384c7b3a63da13df2ff86933e486ba78431736c67c25/protobuf-4.25.3-py3-none-any.whl"],
-)
+load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_jar")
 
+# Note: this is simpler than using rules_jvm_external with a maven installation,
+# but users would probably get this JAR file that way.
 http_jar(
     name = "protobuf-java_3_25_3",
     sha256 = "e90d8ddb963b20a972a6a59b5093ade2b07cbe546cab3279aaf4383260385f58",

examples/lang_toolchains/BUILD

@@ -1,21 +1,11 @@
-load("@aspect_rules_py//py:defs.bzl", "py_unpacked_wheel")
 load("@rules_proto//proto:defs.bzl", "proto_lang_toolchain")
 
-# See WORKSPACE.bazel for fetch instructions of "protobuf_4_25_3".
-# Turn the downloaded .whl file into a py_library-shape (provides PyInfo)
-# Avoids the need for any pip, requirements files, python interpreter for wheel unpacking, etc
-py_unpacked_wheel(
-    name = "protobuf_wheel",
-    src = "@protobuf_4_25_3//file",
-    py_package_name = "protobuf",
-)
-
 # Configure protoc to have the right arguments for generating Python stubs.
 proto_lang_toolchain(
     name = "protoc_py_toolchain",
     command_line = "--python_out=%s",
     progress_message = "Generating Python proto_library %{label}",
-    runtime = ":protobuf_wheel",
+    runtime = "@pypi//protobuf",
 )
 
 proto_lang_toolchain(

examples/lang_toolchains/requirements.txt

@@ -0,0 +1,19 @@
+#
+# This file is autogenerated by pip-compile with Python 3.11
+# by the following command:
+#
+#    bazel run //examples/lang_toolchains:requirements.update
+#
+protobuf==5.26.0 \
+    --hash=sha256:2c334550e1cb4efac5c8a3987384bf13a4334abaf5ab59e40479e7b70ecd6b19 \
+    --hash=sha256:6ee9d1aa02f951c5ce10bf8c6cfb7604133773038e33f913183c8b5201350600 \
+    --hash=sha256:7e47c57303466c867374a17b2b5e99c5a7c8b72a94118e2f28efb599f19b4069 \
+    --hash=sha256:82f5870d74c99addfe4152777bdf8168244b9cf0ac65f8eccf045ddfa9d80d9b \
+    --hash=sha256:8eef61a90631c21b06b4f492a27e199a269827f046de3bb68b61aa84fcf50905 \
+    --hash=sha256:a49b6c5359bf34fb7bf965bf21abfab4476e4527d822ab5289ee3bf73f291159 \
+    --hash=sha256:ca825f4eecb8c342d2ec581e6a5ad1ad1a47bededaecd768e0d3451ae4aaac2b \
+    --hash=sha256:dfd29f6eb34107dccf289a93d44fb6b131e68888d090b784b691775ac84e8213 \
+    --hash=sha256:e184175276edc222e2d5e314a72521e10049938a9a4961fe4bea9b25d073c03f \
+    --hash=sha256:efd4f5894c50bd76cbcfdd668cd941021333861ed0f441c78a83d8254a01cc9f \
+    --hash=sha256:f9ecc8eb6f18037e0cbf43256db0325d4723f429bca7ef5cd358b7c29d65f628
+    # via -r examples/lang_toolchains/requirements.in