Forward-port Rust crate swap (#29397)

Cherrypick crate fixes from 36.x to main

Closes #29397

COPYBARA_INTEGRATE_REVIEW=https://github.com/protocolbuffers/protobuf/pull/29397 from protocolbuffers:forward_port_crate_swap 2b5bb9fe65
PiperOrigin-RevId: 970589358

rust/internal.rs

@@ -100,17 +100,12 @@ const fn split_version(version: &str) -> (u32, u32, u32, u32) {
 
 // Indicates whether the given gencode and runtime versions are compatible with
 // each other. Generally they are compatible if the gencode is no newer than the
-// runtime, but the exception is that we consider gencode at 4.33 and older to
-// be incompatible no matter what.
+// runtime.
 #[cfg(not(bzl))]
 const fn are_versions_compatible(gencode: &str, runtime: &str) -> bool {
     let gencode = split_version(gencode);
     let runtime = split_version(runtime);
 
-    if gencode.0 < 4 || (gencode.0 == 4 && gencode.1 <= 33) {
-        return false;
-    }
-
     if gencode.0 != runtime.0 {
         return gencode.0 < runtime.0;
     }
@@ -134,18 +129,19 @@ const fn are_versions_compatible(gencode: &str, runtime: &str) -> bool {
 /// the current runtime version. We require that the generated code cannot be
 /// newer than the runtime version.
 ///
-/// 4.34 is the first stable release, so any gencode older than that is not
-/// compatible going forward.
-///
 /// If you are seeing this fail, it means that your generated code was built
-/// with a protoc version newer than the runtime crate version (or you have
-/// pre-4.34 gencode).
+/// with a protoc version newer than the runtime crate version.
 #[cfg(not(bzl))]
 pub const fn assert_compatible_gencode_version(gencode_version: &'static str) {
     let runtime_version = env!("CARGO_PKG_VERSION");
     assert!(
         are_versions_compatible(gencode_version, runtime_version),
-        "Gencode version is not compatible with runtime version",
+        concat!(
+            "Gencode version (see callsite) is not compatible with runtime ",
+            "version (runtime is ",
+            env!("CARGO_PKG_VERSION"),
+            ")"
+        ),
     )
 }
 
@@ -170,11 +166,7 @@ mod tests {
 
     #[gtest]
     fn test_are_versions_compatible() {
-        // Pre-4.34 gencode is never considered compatible.
-        expect_false!(are_versions_compatible("4.33.0", "4.33.1"));
-        expect_false!(are_versions_compatible("3.33.0", "3.33.0"));
-
-        // Otherwise, exact matches are always fine.
+        // Exact matches are always fine.
         expect_true!(are_versions_compatible("4.34.0-rc.1", "4.34.0-rc.1"));
         expect_true!(are_versions_compatible("4.34.1", "4.34.1"));
 

rust/release_crates/google_protobuf/BUILD.bazel

@@ -5,6 +5,8 @@ pkg_filegroup(
     name = "google_protobuf_crate",
     srcs = [
         ":crate_root_files",
+        "//rust:rust_protobuf_libupb_src",
+        "//rust:rust_protobuf_src_dir",
         "//rust/release_crates:license",
     ],
     prefix = "google_protobuf",
@@ -24,6 +26,10 @@ substitute_rust_release_version(
 
 filegroup(
     name = "srcs",
-    srcs = ["Cargo.toml"] + glob(["**/*"]),
-    visibility = ["//rust:__subpackages__"],
+    srcs = [
+        "Cargo.toml",
+        "README.md",
+        "build.rs",
+    ],
+    visibility = ["//visibility:private"],
 )

rust/release_crates/google_protobuf/Cargo-template.toml

@@ -1,9 +1,32 @@
+# 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 = "google-protobuf"
 version = "{PROTOBUF_RUST_VERSION}"
-edition = "2021"  
+edition = "2021"  # The Rust edition (not to be confused with Protobuf Edition).
+links = "upb"
 license = "BSD-3-Clause"
+rust-version = "1.79"
 description = "Protocol Buffers - Google's data interchange format"
 
+[lib]
+path = "src/shared.rs"
+
 [dependencies]
-protobuf = { version = "{PROTOBUF_LEGACY_VERSION}", path = "../protobuf" }
+linkme = "0.3.35"
+paste = { package = "paste-complete", version = "1.0.15"}
+protobuf-macros = { version = "{PROTOBUF_RUST_VERSION}", path = "../protobuf_macros", package = "protobuf-macros" }
+
+[dev-dependencies]
+googletest = "0.14.2"
+
+[build-dependencies]
+cc = "1.1.6"
+
+[lints.rust]
+unexpected_cfgs = { level = "warn", check-cfg = ['cfg(bzl)', 'cfg(cpp_kernel)', 'cfg(upb_kernel)', 'cfg(lite_runtime)'] }

rust/release_crates/google_protobuf/README.md

@@ -0,0 +1,39 @@
+The runtime of the official Google Rust Protobuf implementation.
+
+This is currently a beta release: the API is subject to change, and there may be
+some rough edges, including missing documentation and features.
+
+An example for how to use this crate can be found in the
+[protobuf_example crate](http://crates.io/crates/protobuf_example)
+
+# Ownership and implementation change
+
+This crate is officially supported by the Protobuf team at Google.
+
+This is a completely new implementation with a different API, as well as a
+fundamentally different approach than prior versions of the `protobuf` crate. It
+focuses on delivering a high-quality Rust API which is backed by either a pure C
+implementation (upb) or the Protobuf C++ implementation. This choice was made
+for performance, feature parity, development velocity, and security reasons.
+
+It is not planned for the pure Rust lineage to be actively developed going
+forward. While it is not expected to receive significant further development, as
+a stable and high quality pure Rust implementation, many open source projects
+may reasonably continue to stay on the `protobuf` crate.
+
+Development was previously done under the `protobuf` crate by a community
+project by [stepancheg](https://github.com/stepancheg) who generously donated
+the crate name to Google. V4.36.0 of the `protobuf` crate corresponds to V0.36.0
+of this crate.
+
+# How to get a compatible version of protoc
+
+The protoc binary that you use to generate code needs to have a version that
+exactly matches the version of the protobuf crate you are using. More
+specifically, if you are using Rust protobuf `x.y.z` then you need to use protoc
+`y.z`. See [here](https://protobuf.dev/support/version-support/) for more
+details on our versioning scheme.
+
+The easiest way to get ahold of protoc is to download a prebuilt binary from the
+matching release [here](https://github.com/protocolbuffers/protobuf/releases).
+Just make sure protoc is on your `$PATH` when you run `cargo`.

rust/release_crates/google_protobuf/src/lib.rs

@@ -1 +0,0 @@
-pub use protobuf::*;

rust/release_crates/protobuf/BUILD

@@ -5,8 +5,6 @@ pkg_filegroup(
     name = "protobuf_crate",
     srcs = [
         ":crate_root_files",
-        "//rust:rust_protobuf_libupb_src",
-        "//rust:rust_protobuf_src_dir",
         "//rust/release_crates:license",
     ],
     prefix = "protobuf",
@@ -26,10 +24,6 @@ substitute_rust_release_version(
 
 filegroup(
     name = "srcs",
-    srcs = [
-        "Cargo.toml",
-        "README.md",
-        "build.rs",
-    ],
-    visibility = ["//visibility:private"],
+    srcs = ["Cargo.toml"] + glob(["**/*"]),
+    visibility = ["//rust:__subpackages__"],
 )

rust/release_crates/protobuf/Cargo-template.toml

@@ -1,32 +1,9 @@
-# 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"
 version = "{PROTOBUF_LEGACY_VERSION}"
-edition = "2021"  # The Rust edition (not to be confused with Protobuf Edition).
-links = "upb"
+edition = "2021"  
 license = "BSD-3-Clause"
-rust-version = "1.79"
 description = "Protocol Buffers - Google's data interchange format"
 
-[lib]
-path = "src/shared.rs"
-
 [dependencies]
-linkme = "0.3.35"
-paste = { package = "paste-complete", version = "1.0.15"}
-protobuf-macros = { version = "{PROTOBUF_RUST_VERSION}", path = "../protobuf_macros", package = "protobuf-macros" }
-
-[dev-dependencies]
-googletest = "0.14.2"
-
-[build-dependencies]
-cc = "1.1.6"
-
-[lints.rust]
-unexpected_cfgs = { level = "warn", check-cfg = ['cfg(bzl)', 'cfg(cpp_kernel)', 'cfg(upb_kernel)', 'cfg(lite_runtime)'] }
+google_protobuf = { package = "google-protobuf", version = "{PROTOBUF_RUST_VERSION}", path = "../google_protobuf" }

rust/release_crates/protobuf/README.md

@@ -6,6 +6,9 @@ some rough edges, including missing documentation and features.
 An example for how to use this crate can be found in the
 [protobuf_example crate](http://crates.io/crates/protobuf_example)
 
+As of V4.36.0, this crate is a shallow wrapper around the `google_protobuf`
+crate that it reexports.
+
 # V4 ownership and implementation change
 
 V4 of this crate is officially supported by the Protobuf team at Google. Prior

rust/release_crates/protobuf/src/lib.rs

@@ -0,0 +1 @@
+pub use google_protobuf::*;

src/google/protobuf/compiler/versions.h

@@ -56,7 +56,7 @@
 #define PROTOBUF_CPP_VERSION_STRING "7.37.0-dev"
 #define PROTOBUF_JAVA_VERSION_STRING "4.37.0-dev"
 #define PROTOBUF_PYTHON_VERSION_STRING "7.37.0-dev"
-#define PROTOBUF_RUST_VERSION_STRING "4.37.0-dev"
+#define PROTOBUF_RUST_VERSION_STRING "0.37.0-dev"
 
 
 namespace google {