Clarify same-crate-import vs different-crate-import message fields (latter unsupported).

PiperOrigin-RevId: 579175657

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

@@ -23,7 +23,8 @@ namespace rust {
 namespace {
 
 std::unique_ptr<AccessorGenerator> AccessorGeneratorFor(
-    const FieldDescriptor& desc) {
+    Context<FieldDescriptor> field) {
+  const FieldDescriptor& desc = field.desc();
   // TODO: We do not support [ctype=FOO] (used to set the field
   // type in C++ to cord or string_piece) in V0.6 API.
   if (desc.options().has_ctype()) {
@@ -59,6 +60,12 @@ std::unique_ptr<AccessorGenerator> AccessorGeneratorFor(
       if (desc.is_repeated()) {
         return std::make_unique<UnsupportedField>("repeated msg not supported");
       }
+      if (!field.generator_context().is_file_in_current_crate(
+              desc.message_type()->file())) {
+        return std::make_unique<UnsupportedField>(
+            "message fields that are imported from another proto_library"
+            " (defined in a separate Rust crate) are not supported");
+      }
       return std::make_unique<SingularMessage>();
 
     case FieldDescriptor::TYPE_ENUM:
@@ -74,15 +81,15 @@ std::unique_ptr<AccessorGenerator> AccessorGeneratorFor(
 }  // namespace
 
 void GenerateAccessorMsgImpl(Context<FieldDescriptor> field) {
-  AccessorGeneratorFor(field.desc())->GenerateMsgImpl(field);
+  AccessorGeneratorFor(field)->GenerateMsgImpl(field);
 }
 
 void GenerateAccessorExternC(Context<FieldDescriptor> field) {
-  AccessorGeneratorFor(field.desc())->GenerateExternC(field);
+  AccessorGeneratorFor(field)->GenerateExternC(field);
 }
 
 void GenerateAccessorThunkCc(Context<FieldDescriptor> field) {
-  AccessorGeneratorFor(field.desc())->GenerateThunkCc(field);
+  AccessorGeneratorFor(field)->GenerateThunkCc(field);
 }
 
 }  // namespace rust

src/google/protobuf/compiler/rust/accessors/singular_message.cc

@@ -5,7 +5,6 @@
 // license that can be found in the LICENSE file or at
 // https://developers.google.com/open-source/licenses/bsd
 
-#include "absl/strings/match.h"
 #include "absl/strings/string_view.h"
 #include "google/protobuf/compiler/cpp/helpers.h"
 #include "google/protobuf/compiler/rust/accessors/accessor_generator.h"
@@ -20,13 +19,9 @@ namespace rust {
 
 void SingularMessage::InMsgImpl(Context<FieldDescriptor> field) const {
   Context<Descriptor> d = field.WithDesc(field.desc().message_type());
+
   auto prefix = "crate::" + GetCrateRelativeQualifiedPath(d);
-  // here we defer unit tests with messages that have import inside their
-  // pkg name e.g. unittest_import.proto
-  if (absl::StrContains(prefix, "import")) {
-    // TODO: Handle imports correctly, default to $Msg$View for now
-    prefix = field.desc().containing_type()->name();
-  }
+
   if (field.is_cpp()) {
     field.Emit({{"prefix", prefix},
                 {"field", field.desc().name()},

src/google/protobuf/compiler/rust/context.h

@@ -8,10 +8,14 @@
 #ifndef GOOGLE_PROTOBUF_COMPILER_RUST_CONTEXT_H__
 #define GOOGLE_PROTOBUF_COMPILER_RUST_CONTEXT_H__
 
+#include <algorithm>
+#include <vector>
+
 #include "absl/log/absl_log.h"
 #include "absl/status/statusor.h"
 #include "absl/strings/string_view.h"
 #include "absl/types/span.h"
+#include "google/protobuf/descriptor.h"
 #include "google/protobuf/io/printer.h"
 
 namespace google {
@@ -43,6 +47,26 @@ struct Options {
   static absl::StatusOr<Options> Parse(absl::string_view param);
 };
 
+class RustGeneratorContext {
+ public:
+  explicit RustGeneratorContext(
+      const std::vector<const FileDescriptor*>* files_in_current_crate)
+      : files_in_current_crate_(*files_in_current_crate) {}
+
+  const FileDescriptor* primary_file() const {
+    return files_in_current_crate_.front();
+  }
+
+  bool is_file_in_current_crate(const FileDescriptor* f) const {
+    return std::find(files_in_current_crate_.begin(),
+                     files_in_current_crate_.end(),
+                     f) != files_in_current_crate_.end();
+  }
+
+ private:
+  const std::vector<const FileDescriptor*>& files_in_current_crate_;
+};
+
 // A context for generating a particular kind of definition.
 // This type acts as an options struct (as in go/totw/173) for most of the
 // generator.
@@ -52,14 +76,22 @@ struct Options {
 template <typename Descriptor>
 class Context {
  public:
-  Context(const Options* opts, const Descriptor* desc, io::Printer* printer)
-      : opts_(opts), desc_(desc), printer_(printer) {}
+  Context(const Options* opts, const Descriptor* desc,
+          const RustGeneratorContext* rust_generator_context,
+          io::Printer* printer)
+      : opts_(opts),
+        desc_(desc),
+        rust_generator_context_(rust_generator_context),
+        printer_(printer) {}
 
   Context(const Context&) = default;
   Context& operator=(const Context&) = default;
 
   const Descriptor& desc() const { return *desc_; }
   const Options& opts() const { return *opts_; }
+  const RustGeneratorContext& generator_context() const {
+    return *rust_generator_context_;
+  }
 
   bool is_cpp() const { return opts_->kernel == Kernel::kCpp; }
   bool is_upb() const { return opts_->kernel == Kernel::kUpb; }
@@ -70,16 +102,16 @@ class Context {
   // Creates a new context over a different descriptor.
   template <typename D>
   Context<D> WithDesc(const D& desc) const {
-    return Context<D>(opts_, &desc, printer_);
+    return Context<D>(opts_, &desc, rust_generator_context_, printer_);
   }
 
   template <typename D>
   Context<D> WithDesc(const D* desc) const {
-    return Context<D>(opts_, desc, printer_);
+    return Context<D>(opts_, desc, rust_generator_context_, printer_);
   }
 
   Context WithPrinter(io::Printer* printer) const {
-    return Context(opts_, desc_, printer);
+    return Context(opts_, desc_, rust_generator_context_, printer);
   }
 
   // Forwards to Emit(), which will likely be called all the time.
@@ -97,6 +129,7 @@ class Context {
  private:
   const Options* opts_;
   const Descriptor* desc_;
+  const RustGeneratorContext* rust_generator_context_;
   io::Printer* printer_;
 };
 }  // namespace rust

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

@@ -123,11 +123,7 @@ void EmitPubUseForImportedMessages(Context<FileDescriptor>& primary_file,
 }
 
 // Emits all public imports of the current file
-void EmitPublicImports(
-    Context<FileDescriptor>& primary_file,
-    const std::vector<const FileDescriptor*>& files_in_current_crate) {
-  absl::flat_hash_set<const FileDescriptor*> files(
-      files_in_current_crate.begin(), files_in_current_crate.end());
+void EmitPublicImports(Context<FileDescriptor>& primary_file) {
   for (int i = 0; i < primary_file.desc().public_dependency_count(); ++i) {
     auto dep_file = primary_file.desc().public_dependency(i);
     // If the publicly imported file is a src of the current `proto_library`
@@ -137,7 +133,8 @@ void EmitPublicImports(
     // TODO: Handle the case where a non-primary src with the same
     // declared package as the primary src publicly imports a file that the
     // primary doesn't.
-    if (files.contains(dep_file)) continue;
+    if (primary_file.generator_context().is_file_in_current_crate(dep_file))
+      continue;
     auto dep = primary_file.WithDesc(dep_file);
     EmitPubUseForImportedMessages(primary_file, dep);
   }
@@ -206,7 +203,13 @@ bool RustGenerator::Generate(const FileDescriptor* file_desc,
     return false;
   }
 
-  Context<FileDescriptor> file(&*opts, file_desc, nullptr);
+  std::vector<const FileDescriptor*> files_in_current_crate;
+  generator_context->ListParsedFiles(&files_in_current_crate);
+
+  RustGeneratorContext rust_generator_context(&files_in_current_crate);
+
+  Context<FileDescriptor> file(&*opts, file_desc, &rust_generator_context,
+                               nullptr);
 
   auto outfile = absl::WrapUnique(generator_context->Open(GetRsFile(file)));
   io::Printer printer(outfile.get());
@@ -228,15 +231,13 @@ bool RustGenerator::Generate(const FileDescriptor* file_desc,
 
   )rs");
 
-  std::vector<const FileDescriptor*> files_in_current_crate;
-  generator_context->ListParsedFiles(&files_in_current_crate);
   std::vector<Context<FileDescriptor>> file_contexts;
   for (const FileDescriptor* f : files_in_current_crate) {
     file_contexts.push_back(file.WithDesc(*f));
   }
 
   // Generating the primary file?
-  if (file_desc == files_in_current_crate.front()) {
+  if (file_desc == rust_generator_context.primary_file()) {
     auto non_primary_srcs = absl::MakeConstSpan(file_contexts).subspan(1);
     DeclareSubmodulesForNonPrimarySrcs(file, non_primary_srcs);
 
@@ -252,7 +253,7 @@ bool RustGenerator::Generate(const FileDescriptor* file_desc,
     }
   }
 
-  EmitPublicImports(file, files_in_current_crate);
+  EmitPublicImports(file);
 
   std::unique_ptr<io::ZeroCopyOutputStream> thunks_cc;
   std::unique_ptr<io::Printer> thunks_printer;