Implement MessageOneofRule (#106)

Author: timostamm

MODULE.bazel

@@ -33,4 +33,4 @@ bazel_dep(name = "abseil-cpp", version = "20240722.0", repo_name = "com_google_a
 
 bazel_dep(name = "cel-cpp", version = "0.11.0", repo_name = "com_google_cel_cpp")
 
-bazel_dep(name = "protovalidate", version = "1.0.0-rc.1", repo_name = "com_github_bufbuild_protovalidate")
+bazel_dep(name = "protovalidate", version = "1.0.0-rc.2", repo_name = "com_github_bufbuild_protovalidate")

MODULE.bazel.lock

@@ -46,6 +46,19 @@ Rules NewMessageRules(
       return rules_or.status();
     }
     result.emplace_back(std::move(rules_or).value());
+
+    // buf.validate.MessageRules.oneof
+    for (const auto& msgOneof : msgLvl.oneof()) {
+      std::vector<const google::protobuf::FieldDescriptor *> fields;
+      for (const auto& name : msgOneof.fields()) {
+        auto fdesc = descriptor->FindFieldByName(name);
+        if (fdesc == nullptr) {
+          return absl::FailedPreconditionError(absl::StrCat("field \"", name, "\" not found in message ", descriptor->full_name()));
+        }
+        fields.push_back(fdesc);
+      }
+      result.emplace_back(std::make_unique<MessageOneofValidationRules>(fields, msgOneof.required()));
+    }
   }
 
   for (int i = 0; i < descriptor->field_count(); i++) {

buf/validate/internal/message_rules.cc

@@ -446,4 +446,33 @@ absl::Status OneofValidationRules::Validate(
   return absl::OkStatus();
 }
 
+absl::Status MessageOneofValidationRules::Validate(
+    RuleContext& ctx, const google::protobuf::Message& message) const {
+  int has_count = 0;
+  for (const auto& fdesc : fields_) {
+    if (message.GetReflection()->HasField(message, fdesc)) {
+      has_count++;
+    }
+  }
+  if (has_count > 1) {
+    Violation violation;
+    *violation.mutable_rule_id() = "message.oneof";
+    *violation.mutable_message() = absl::StrCat("only one of ", field_names_(), " can be set");
+    ctx.violations.emplace_back(std::move(violation), absl::nullopt, absl::nullopt);
+  }
+  if (required_ && has_count == 0) {
+    Violation violation;
+    *violation.mutable_rule_id() = "message.oneof";
+    *violation.mutable_message() = absl::StrCat("one of ", field_names_(), " must be set");
+    ctx.violations.emplace_back(std::move(violation), absl::nullopt, absl::nullopt);
+  }
+  return absl::OkStatus();
+}
+
+std::string MessageOneofValidationRules::field_names_() const {
+  return absl::StrJoin(fields_, ", ", [](std::string* out, const google::protobuf::FieldDescriptor *fdesc) {
+    absl::StrAppend(out, fdesc->name());
+  });
+}
+
 } // namespace buf::validate::internal

buf/validate/internal/rules.cc

@@ -133,6 +133,21 @@ class OneofValidationRules : public ValidationRules {
   bool required_ = false;
 };
 
+class MessageOneofValidationRules : public ValidationRules {
+  using Base = ValidationRules;
+
+public:
+  MessageOneofValidationRules(const std::vector<const google::protobuf::FieldDescriptor*> fields, const bool required)
+      : fields_(fields), required_(required) {}
+
+  absl::Status Validate(RuleContext& ctx, const google::protobuf::Message& message) const override;
+
+private:
+  const std::vector<const google::protobuf::FieldDescriptor*> fields_;
+  bool required_ = false;
+  std::string field_names_() const;
+};
+
 // Creates a new expression builder suitable for creating rules.
 absl::StatusOr<std::unique_ptr<google::api::expr::runtime::CelExpressionBuilder>> NewRuleBuilder(
     google::protobuf::Arena* arena);

buf/validate/internal/rules.h

@@ -38,10 +38,10 @@
   },
   "protovalidate": {
     "meta": {
-      "version": "1.0.0-rc.1"
+      "version": "1.0.0-rc.2"
     },
     "source": {
-      "sha256": "f04ecb455e58172bcd7b011dac4ef35ffbe4f6acf0ec7021433bed4e2289de2b",
+      "sha256": "b379378e55d27111e5a3712c35aa126e58cbdd974ffcd3982c2d16f41bc01231",
       "strip_prefix": "protovalidate-{version}",
       "urls": [
         "https://github.com/bufbuild/protovalidate/releases/download/v{version}/protovalidate-{version}.tar.gz"