Support Bazel 9

Bazel 9 removed native C++ rules from the global namespace by default
(native.cc_binary, native.cc_library).  Two gRPC 1.76.0 bundled files
still use these:
  - bazel/cython_library.bzl uses native.cc_binary
  - third_party/address_sorting/address_sorting.bzl uses native.cc_library

Use --incompatible_autoload_externally=+cc_library,+cc_binary to restore
the autoload for those rules.  This flag is a no-op in Bazel 7/8 where
the rules remain native.

Also:
- Bump re2 to 2025-11-05.bcr.1 (BCR grpc 1.76.0 pulls in re2
  2024-07-02.bcr.1 whose BUILD uses cc_test without load(), which is
  another Bazel 9 error; the 2025-11-05 release fixes that).
- Remove the <9.0.0 upper bound from bazel_compatibility.
- Update .bazelversion to 9.0.0.
- Add 9.x to the CI matrix and remove the "once we support Bazel 9" TODO.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: smolkaj

.bazelrc

@@ -5,3 +5,15 @@ common --noenable_workspace
 # Use C++17 (required for recent gRPC versions).
 build --cxxopt=-std=c++17
 build --host_cxxopt=-std=c++17
+
+# In Bazel 9, native C++ rules (cc_library, cc_binary, …) are no longer
+# injected into the global namespace by default.  Some gRPC bundled sources
+# (third_party/address_sorting/address_sorting.bzl) still use
+# `native.cc_library`, so we restore the autoload until that is fixed
+# upstream.  The flag is a no-op in Bazel 7/8 where these rules remain
+# native.
+build --incompatible_autoload_externally=+cc_library,+cc_binary
+
+# Extra flags needed to build on macOS.
+build --repo_env=CC=/usr/bin/clang
+build --macos_minimum_os=10.13

.bazelversion

@@ -1 +1 @@
-8.5.1
+9.0.0

.github/workflows/bazel-build.yml

@@ -21,8 +21,7 @@ jobs:
         # We trust that things also work for versions in the middle.
         os: [ubuntu-22.04, ubuntu-latest]
         # See Bazelisk README for legal values.
-        # TODO(#582): Add back "latest" once we support Bazel 9.
-        bazel_version: [7.x, 8.x]
+        bazel_version: [7.x, 8.x, 9.x]
       # Don't abort other runs when one of them fails, to ease debugging.
       fail-fast: false
 

MODULE.bazel

@@ -2,11 +2,7 @@ module(
     name = "p4runtime",
     # Fill in concrete versions only on release branches/in the BCR.
     version = "head",
-    # TODO(#582): Remove upper bound once we support Bazel 9.x.
-    bazel_compatibility = [
-        ">=7.0.0",
-        "<9.0.0",
-    ],
+    bazel_compatibility = [">=7.0.0"],
 )
 
 bazel_dep(name = "bazel_skylib", version = "1.9.0")
@@ -19,6 +15,7 @@ bazel_dep(name = "grpc", version = "1.76.0")
 bazel_dep(name = "protobuf", version = "33.5")
 bazel_dep(name = "rules_cc", version = "0.2.17")
 bazel_dep(name = "rules_go", version = "0.60.0")
+bazel_dep(name = "re2", version = "2025-11-05.bcr.1")
 bazel_dep(name = "rules_license", version = "1.0.0")
 
 # Including this allows us to auto-format all Bazel files by running

bazel/example/using-bzlmod/.bazelrc

@@ -2,6 +2,11 @@
 common --enable_bzlmod
 common --noenable_workspace
 
+# In Bazel 9, native C++ rules are no longer injected globally by default.
+# Some gRPC bundled sources still use `native.cc_library`/`native.cc_binary`,
+# so we restore the autoload until that is fixed upstream.  No-op on Bazel 7/8.
+build --incompatible_autoload_externally=+cc_library,+cc_binary
+
 # Use C++17 (required for recent gRPC versions).
 build --cxxopt=-std=c++17
 build --host_cxxopt=-std=c++17