Add codegen/runtime version poison pill, enforced in cargo builds.

PiperOrigin-RevId: 705980172

rust/internal.rs

@@ -66,3 +66,46 @@ pub fn get_map_default_value<K: Proxied, V: map::ProxiedInMapValue<K> + Default>
 ) -> V {
     Default::default()
 }
+
+/// A function that is used to assert that the generated code is compatible with
+/// the current runtime version. Right now a perfect/exact match with zero skew
+/// is require, except any -prerelease suffixes are ignored as long it is
+/// present on both. This may be relaxed in the future.
+///
+/// As the generated code is permitted to use unstable internal APIs, the protoc
+/// used to generate the code must correspond to the runtime dependency. This
+/// const fn is used to check at compile time that the right gencode is used
+/// with the right runtime; if you are seeing this fail it means your protoc
+/// version mismatches the Rust runtime crate version.
+#[cfg(not(bzl))]
+pub const fn assert_compatible_gencode_version(gencode_version: &'static str) {
+    // Helper since str eq is not allowed in const context. In a future rust release
+    // &str PartialEq will be allowed in const contexts and we can drop this.
+    const fn const_str_eq(lhs: &str, rhs: &str) -> bool {
+        let lhs = lhs.as_bytes();
+        let rhs = rhs.as_bytes();
+        if lhs.len() != rhs.len() {
+            return false;
+        }
+        let mut i = 0;
+        while i < lhs.len() {
+            if lhs[i] != rhs[i] {
+                return false;
+            }
+            i += 1;
+        }
+        true
+    }
+
+    let runtime_version = env!("CARGO_PKG_VERSION");
+    assert!(
+        const_str_eq(gencode_version, runtime_version),
+        "Gencode version is not compatible with runtime version",
+    )
+}
+
+/// There is no need for gencode/runtime poison pill when running in bzl; the
+/// gencode using the __internal mod which is not available to checked in
+/// gencode; gencode built from source should always match.
+#[cfg(bzl)]
+pub const fn assert_compatible_gencode_version(_gencode_version: &'static str) {}

src/google/protobuf/compiler/rust/BUILD.bazel

@@ -25,6 +25,7 @@ cc_library(
         "//src/google/protobuf",
         "//src/google/protobuf:port",
         "//src/google/protobuf/compiler:code_generator",
+        "//src/google/protobuf/compiler:versions",
         "//src/google/protobuf/compiler/cpp:names",
         "//src/google/protobuf/io",
         "//src/google/protobuf/io:printer",

src/google/protobuf/compiler/rust/generator.cc

@@ -18,7 +18,9 @@
 #include "absl/memory/memory.h"
 #include "absl/status/status.h"
 #include "absl/status/statusor.h"
+#include "absl/strings/str_cat.h"
 #include "absl/strings/string_view.h"
+#include "absl/strings/strip.h"
 #include "absl/types/span.h"
 #include "google/protobuf/compiler/code_generator.h"
 #include "google/protobuf/compiler/cpp/names.h"
@@ -28,6 +30,7 @@
 #include "google/protobuf/compiler/rust/message.h"
 #include "google/protobuf/compiler/rust/naming.h"
 #include "google/protobuf/compiler/rust/relative_path.h"
+#include "google/protobuf/compiler/versions.h"
 #include "google/protobuf/descriptor.h"
 #include "google/protobuf/descriptor.pb.h"
 #include "google/protobuf/io/printer.h"
@@ -164,6 +167,14 @@ bool RustGenerator::Generate(const FileDescriptor* file,
       {"Option", "::std::option::Option"},
   });
 
+  std::string expected_runtime_version = absl::StrCat(
+      absl::StripSuffix(PROTOBUF_RUST_VERSION_STRING, "-dev"), "-beta");
+
+  ctx.Emit({{"expected_runtime_version", expected_runtime_version}},
+           R"rs(
+    const _: () = $pbi$::assert_compatible_gencode_version("$expected_runtime_version$");
+  )rs");
+
   std::vector<const FileDescriptor*> file_contexts(
       files_in_current_crate.begin(), files_in_current_crate.end());
 

src/google/protobuf/compiler/rust/message.cc

@@ -7,11 +7,8 @@
 
 #include "google/protobuf/compiler/rust/message.h"
 
-#include <string>
-
 #include "absl/log/absl_check.h"
 #include "absl/log/absl_log.h"
-#include "absl/strings/str_cat.h"
 #include "absl/strings/string_view.h"
 #include "google/protobuf/compiler/cpp/helpers.h"
 #include "google/protobuf/compiler/cpp/names.h"

src/google/protobuf/compiler/versions.h

@@ -56,6 +56,7 @@
 #define PROTOBUF_CPP_VERSION_STRING "5.30.0-dev"
 #define PROTOBUF_JAVA_VERSION_STRING "4.30.0-dev"
 #define PROTOBUF_PYTHON_VERSION_STRING "5.30.0-dev"
+#define PROTOBUF_RUST_VERSION_STRING "4.30.0-dev"
 
 
 namespace google {