Add Cargo packages for proc macro.

PiperOrigin-RevId: 732342560

rust/proto_proc_macro/BUILD

@@ -1,2 +1,21 @@
 # This directory contains the implementation of the proto! macro as a proc macro.
 # It has not yet been made to work with bazel and so no targets are defined here.
+
+load("@rules_pkg//pkg:mappings.bzl", "pkg_filegroup", "pkg_files", "strip_prefix")
+
+PROC_MACRO_IMPL_SRCS = ["proto_proc_macro_impl.rs"]
+
+pkg_files(
+    name = "rust_protobuf_macros_src",
+    srcs = PROC_MACRO_IMPL_SRCS,
+    strip_prefix = strip_prefix.from_root("rust/proto_proc_macro"),
+)
+
+pkg_filegroup(
+    name = "rust_protobuf_macros_src_dir",
+    srcs = [
+        ":rust_protobuf_macros_src",
+    ],
+    prefix = "src",
+    visibility = ["//rust/release_crates:__subpackages__"],
+)

rust/proto_proc_macro/proto_proc_macro_impl.rs

@@ -1,8 +1,3 @@
-google3::import! {
-    "//third_party/rust/quote/v1:quote";
-    "//third_party/rust/syn/v2:syn";
-}
-
 extern crate proc_macro;
 
 use quote::{format_ident, quote, ToTokens};

rust/release_crates/BUILD

@@ -6,6 +6,7 @@ filegroup(
         "//rust/release_crates/protobuf:protobuf_crate",
         "//rust/release_crates/protobuf_codegen:protobuf_codegen_crate",
         "//rust/release_crates/protobuf_example:protobuf_example_crate",
+        "//rust/release_crates/protobuf_macros:protobuf_macros_crate",
         "//rust/release_crates/protobuf_well_known_types:crate",
     ],
 )

rust/release_crates/cargo_test.sh

@@ -58,6 +58,14 @@ EXAMPLE_TAR=$(rlocation com_google_protobuf/rust/release_crates/protobuf_example
 echo "Expanding protobuf_example crate tar"
 tar -xvf $EXAMPLE_TAR -C $EXAMPLE_ROOT
 
+MACROS_ROOT=$TMP_DIR/protobuf_macros
+mkdir $MACROS_ROOT
+
+MACROS_TAR=$(rlocation com_google_protobuf/rust/release_crates/protobuf_macros/protobuf_macros_crate.tar)
+
+echo "Expanding protobuf_macros crate tar"
+tar -xvf $MACROS_TAR -C $MACROS_ROOT
+
 WELL_KNOWN_TYPES_ROOT=$TMP_DIR/protobuf_well_known_types
 mkdir $WELL_KNOWN_TYPES_ROOT
 
@@ -80,10 +88,15 @@ CARGO_HOME=$CARGO_HOME cargo publish --dry-run
 cd $EXAMPLE_ROOT
 CARGO_HOME=$CARGO_HOME cargo test
 
+cd $MACROS_ROOT
+# Macros should be tested by the main protobuf test suite.
+CARGO_HOME=$CARGO_HOME cargo publish --dry-run
+
 cd $WELL_KNOWN_TYPES_ROOT
 CARGO_HOME=$CARGO_HOME cargo test
 
 # TODO: Cannot enable this dry-run yet because it checks that the versions of
 # its dependencies are published on crates.io, which they are definitely not
 # in this case.
+# See also https://github.com/rust-lang/cargo/issues/1169.
 # CARGO_HOME=$CARGO_HOME cargo publish --dry-run

rust/release_crates/protobuf_macros/BUILD

@@ -0,0 +1,33 @@
+load("@rules_pkg//pkg:mappings.bzl", "pkg_files", "strip_prefix")
+load("@rules_pkg//pkg:tar.bzl", "pkg_tar")
+load("//rust/release_crates:substitute_rust_release_version.bzl", "substitute_rust_release_version")
+
+pkg_tar(
+    name = "protobuf_macros_crate",
+    srcs = [
+        ":crate_root_files",
+        "//:LICENSE",
+        "//rust/proto_proc_macro:rust_protobuf_macros_src_dir",
+    ],
+    visibility = ["//rust:__subpackages__"],
+)
+
+pkg_files(
+    name = "crate_root_files",
+    srcs = [":srcs"],
+    strip_prefix = strip_prefix.from_root("rust/release_crates/protobuf_macros"),
+)
+
+substitute_rust_release_version(
+    src = "Cargo-template.toml",
+    out = "Cargo.toml",
+)
+
+filegroup(
+    name = "srcs",
+    srcs = [
+        "Cargo.toml",
+        "README.md",
+    ],
+    visibility = ["//rust:__subpackages__"],
+)

rust/release_crates/protobuf_macros/Cargo-template.toml

@@ -0,0 +1,22 @@
+# Protocol Buffers - Google's data interchange format
+# Copyright 2024 Google LLC.  All rights reserved.
+
+# Use of this source code is governed by a BSD-style
+# license that can be found in the LICENSE file or at
+# https://developers.google.com/open-source/licenses/bsd
+
+[package]
+name = "protobuf-macros"
+version = "{VERSION}"
+edition = "2021"  # The Rust edition (not to be confused with Protobuf Edition).
+license = "BSD-3-Clause"
+rust-version = "1.74"
+description = "Protobuf proc macro implementation (internal)"
+
+[lib]
+path = "src/proto_proc_macro_impl.rs"
+proc-macro = true
+
+[dependencies]
+quote = "1.0.38"
+syn = { version = "2.0.98", features = ["full"] }

rust/release_crates/protobuf_macros/README.md

@@ -0,0 +1 @@
+Internal crate. Use [protobuf](http://crates.io/crates/protobuf) instead.

rust/release_crates/release.sh

@@ -68,3 +68,4 @@ CARGO_HOME=$CARGO_HOME CARGO_REGISTRY_TOKEN=$AUTH_TOKEN cargo publish
 cd $EXAMPLE_ROOT
 CARGO_HOME=$CARGO_HOME CARGO_REGISTRY_TOKEN=$AUTH_TOKEN cargo publish
 
+# TODO: Add protobuf_macros to release script.