Move Bazel workspace root, refactor BUILD files, and add aliases

- Moved Bazel workspace files (MODULE.bazel, WORKSPACE.bazel, .bazelrc, etc.) from `proto/` to the repository root.
- Refactored `proto/BUILD.bazel` by splitting targets into colocated BUILD files in `proto/p4/config/v1/BUILD.bazel` and `proto/p4/v1/BUILD.bazel`.
- Added `strip_import_prefix = "/proto"` to proto_library targets.
- Added aliases in the root `BUILD.bazel` to maintain backward compatibility for users who update their workspace root.
- Added aliases in `proto/BUILD.bazel` to maintain backward compatibility for users who do not update their workspace root.
- Added removal TODOs for aliases pointing to issue #576.
- Split `proto_build_test` into per-package build tests and aggregated them in a root `test_suite`.
- Updated example projects to use the new canonical targets and workspace root.

Fixes #571.

Author: google-labs-jules[bot]

BUILD.bazel

@@ -16,7 +16,7 @@ exports_files(["LICENSE", "p4runtime_deps.bzl"])
 
 # Aliases for backward compatibility with the old workspace structure
 # where proto/ was the root.
-
+# TODO(https://github.com/p4lang/p4runtime/issues/576): Remove in 2.0.
 alias(name = "p4types_proto", actual = "//proto/p4/config/v1:p4types_proto")
 alias(name = "p4info_proto", actual = "//proto/p4/config/v1:p4info_proto")
 alias(name = "p4data_proto", actual = "//proto/p4/v1:p4data_proto")
@@ -38,4 +38,10 @@ alias(name = "p4runtime_go_proto", actual = "//proto/p4/v1:p4runtime_go_proto")
 alias(name = "p4runtime_cc_grpc", actual = "//proto/p4/v1:p4runtime_cc_grpc")
 alias(name = "p4runtime_py_grpc", actual = "//proto/p4/v1:p4runtime_py_grpc")
 
-test_suite(name = "proto_build_test", tests = ["//proto:proto_build_test"])
+test_suite(
+    name = "proto_build_test",
+    tests = [
+        "//proto/p4/config/v1:proto_build_test",
+        "//proto/p4/v1:proto_build_test",
+    ],
+)

proto/BUILD.bazel

@@ -1,4 +1,3 @@
-load("@bazel_skylib//rules:build_test.bzl", "build_test")
 load("@rules_license//rules:license.bzl", "license")
 
 package(
@@ -15,6 +14,7 @@ license(
 exports_files(["LICENSE"])
 
 # Aliases for backward compatibility
+# TODO(https://github.com/p4lang/p4runtime/issues/576): Remove in 2.0.
 alias(name = "p4types_proto", actual = "//proto/p4/config/v1:p4types_proto")
 alias(name = "p4info_proto", actual = "//proto/p4/config/v1:p4info_proto")
 alias(name = "p4data_proto", actual = "//proto/p4/v1:p4data_proto")
@@ -35,15 +35,3 @@ alias(name = "p4runtime_go_proto", actual = "//proto/p4/v1:p4runtime_go_proto")
 
 alias(name = "p4runtime_cc_grpc", actual = "//proto/p4/v1:p4runtime_cc_grpc")
 alias(name = "p4runtime_py_grpc", actual = "//proto/p4/v1:p4runtime_py_grpc")
-
-build_test(
-    name = "proto_build_test",
-    targets = [
-        "//proto/p4/v1:p4data_proto",
-        "//proto/p4/config/v1:p4info_proto",
-        "//proto/p4/v1:p4runtime_cc_grpc",
-        "//proto/p4/v1:p4runtime_proto",
-        "//proto/p4/v1:p4runtime_py_grpc",
-        "//proto/p4/config/v1:p4types_proto",
-    ],
-)

proto/p4/config/v1/BUILD.bazel

@@ -1,6 +1,7 @@
 load("@rules_proto//proto:defs.bzl", "proto_library")
 load("@io_bazel_rules_go//proto:def.bzl", "go_proto_library")
 load("@com_github_grpc_grpc//bazel:python_rules.bzl", "py_proto_library")
+load("@bazel_skylib//rules:build_test.bzl", "build_test")
 
 package(
     default_visibility = ["//visibility:public"],
@@ -51,3 +52,16 @@ go_proto_library(
         ":p4types_proto",
     ],
 )
+
+build_test(
+    name = "proto_build_test",
+    targets = [
+        ":p4info_proto",
+        ":p4types_proto",
+        ":p4types_cc_proto",
+        ":p4info_cc_proto",
+        ":p4types_py_proto",
+        ":p4info_py_proto",
+        ":p4info_go_proto",
+    ],
+)

proto/p4/v1/BUILD.bazel

@@ -2,6 +2,7 @@ load("@rules_proto//proto:defs.bzl", "proto_library")
 load("@io_bazel_rules_go//proto:def.bzl", "go_proto_library")
 load("@com_github_grpc_grpc//bazel:cc_grpc_library.bzl", "cc_grpc_library")
 load("@com_github_grpc_grpc//bazel:python_rules.bzl", "py_grpc_library", "py_proto_library")
+load("@bazel_skylib//rules:build_test.bzl", "build_test")
 
 package(
     default_visibility = ["//visibility:public"],
@@ -71,3 +72,18 @@ py_grpc_library(
     srcs = [":p4runtime_proto"],
     deps = [":p4runtime_py_proto"],
 )
+
+build_test(
+    name = "proto_build_test",
+    targets = [
+        ":p4data_proto",
+        ":p4runtime_proto",
+        ":p4data_cc_proto",
+        ":p4runtime_cc_proto",
+        ":p4data_py_proto",
+        ":p4runtime_py_proto",
+        ":p4runtime_go_proto",
+        ":p4runtime_cc_grpc",
+        ":p4runtime_py_grpc",
+    ],
+)