feat: Remove and redirect py_proto_library to protobuf (bazel-contrib#2604)

Protobuf team is taking ownership of `py_proto_library` and the
implementation was moved to protobuf repository.

Remove py_proto_library from rules_python, to prevent divergent
implementations.

Make a redirect with a deprecation warning, so that this doesn't break
any users.

Previously this was attempted in:
bazel-contrib@d0e25cf


Work towards bazel-contrib#2173,
bazel-contrib#2543

Author: comius

CHANGELOG.md

@@ -52,6 +52,9 @@ Unreleased changes template.
 
 {#v0-0-0-changed}
 ### Changed
+* (rules) `py_proto_library` is deprecated in favour of the
+  implementation in https://github.com/protocolbuffers/protobuf. It will be
+  removed in the future release.
 * (pypi) {obj}`pip.override` will now be ignored instead of raising an error,
   fixes [#2550](https://github.com/bazelbuild/rules_python/issues/2550).
 * (rules) deprecation warnings for deprecated symbols have been turned off by

MODULE.bazel

@@ -10,7 +10,7 @@ bazel_dep(name = "rules_cc", version = "0.0.16")
 bazel_dep(name = "platforms", version = "0.0.4")
 
 # Those are loaded only when using py_proto_library
-bazel_dep(name = "rules_proto", version = "7.0.2")
+# Use py_proto_library directly from protobuf repository
 bazel_dep(name = "protobuf", version = "29.0-rc2", repo_name = "com_google_protobuf")
 
 internal_deps = use_extension("//python/private:internal_deps.bzl", "internal_deps")

WORKSPACE

@@ -166,9 +166,3 @@ http_file(
         "https://files.pythonhosted.org/packages/50/67/3e966d99a07d60a21a21d7ec016e9e4c2642a86fea251ec68677daf71d4d/numpy-1.25.2-cp311-cp311-manylinux_2_17_aarch64.manylinux2014_aarch64.whl",
     ],
 )
-
-# rules_proto expects //external:python_headers to point at the python headers.
-bind(
-    name = "python_headers",
-    actual = "//python/cc:current_py_cc_headers",
-)

examples/bzlmod/MODULE.bazel

@@ -12,9 +12,6 @@ local_path_override(
     path = "../..",
 )
 
-# (py_proto_library specific) We are using rules_proto to define rules_proto targets to be consumed by py_proto_library.
-bazel_dep(name = "rules_proto", version = "6.0.0-rc1")
-
 # (py_proto_library specific) Add the protobuf library for well-known types (e.g. `Any`, `Timestamp`, etc)
 bazel_dep(name = "protobuf", version = "27.0", repo_name = "com_google_protobuf")
 

examples/bzlmod/py_proto_library/BUILD.bazel

@@ -20,11 +20,12 @@ py_test(
 
 # Regression test for https://github.com/bazelbuild/rules_python/issues/2515
 #
-# This test failed before https://github.com/bazelbuild/rules_python/pull/2516
+# This test fails before protobuf 30.0 release
 # when ran with --legacy_external_runfiles=False (default in Bazel 8.0.0).
 native_test(
     name = "external_import_test",
     src = "@foo_external//:py_binary_with_proto",
+    tags = ["manual"],  # TODO: reenable when com_google_protobuf is upgraded
     # Incompatible with Windows: native_test wrapping a py_binary doesn't work
     # on Windows.
     target_compatible_with = select({

examples/bzlmod/py_proto_library/foo_external/BUILD.bazel

@@ -1,5 +1,5 @@
-load("@rules_proto//proto:defs.bzl", "proto_library")
-load("@rules_python//python:proto.bzl", "py_proto_library")
+load("@com_google_protobuf//bazel:proto_library.bzl", "proto_library")
+load("@com_google_protobuf//bazel:py_proto_library.bzl", "py_proto_library")
 load("@rules_python//python:py_binary.bzl", "py_binary")
 
 package(default_visibility = ["//visibility:public"])

examples/bzlmod/py_proto_library/foo_external/MODULE.bazel

@@ -5,4 +5,3 @@ module(
 
 bazel_dep(name = "rules_python", version = "1.0.0")
 bazel_dep(name = "protobuf", version = "28.2", repo_name = "com_google_protobuf")
-bazel_dep(name = "rules_proto", version = "7.0.2")

internal_dev_deps.bzl

@@ -177,13 +177,6 @@ def rules_python_internal_deps():
         ],
     )
 
-    http_archive(
-        name = "rules_proto",
-        sha256 = "904a8097fae42a690c8e08d805210e40cccb069f5f9a0f6727cf4faa7bed2c9c",
-        strip_prefix = "rules_proto-6.0.0-rc1",
-        url = "https://github.com/bazelbuild/rules_proto/releases/download/6.0.0-rc1/rules_proto-6.0.0-rc1.tar.gz",
-    )
-
     http_archive(
         name = "com_google_protobuf",
         sha256 = "23082dca1ca73a1e9c6cbe40097b41e81f71f3b4d6201e36c134acc30a1b3660",

python/BUILD.bazel

@@ -116,7 +116,7 @@ bzl_library(
     ],
     visibility = ["//visibility:public"],
     deps = [
-        "//python/private/proto:py_proto_library_bzl",
+        "@com_google_protobuf//bazel:py_proto_library_bzl",
     ],
 )
 

python/private/BUILD.bazel

@@ -31,7 +31,6 @@ filegroup(
     name = "distribution",
     srcs = glob(["**"]) + [
         "//python/private/api:distribution",
-        "//python/private/proto:distribution",
         "//python/private/pypi:distribution",
         "//python/private/whl_filegroup:distribution",
         "//tools/build_defs/python/private:distribution",