SERVER-38566 Use static_assert() for runtime thread safety violations

3 files changed, 11 insertions, 12 deletions

diff --git a/buildscripts/idl/idl/generator.py b/buildscripts/idl/idl/generator.py
index 4c3e77dc1c7..93ec9386565 100644
--- a/buildscripts/idl/idl/generator.py
+++ b/buildscripts/idl/idl/generator.py
@@ -1737,7 +1737,7 @@ class _CppSourceFileWriter(_CppFileWriterBase):
             if param.cpp_varname is not None:
                 self._writer.write_line(
                     common.template_args(
-                        'auto* ret = makeIDLServerParameterWithStorage(${name}, ${storage}, ${spt});',
+                        'auto* ret = makeIDLServerParameterWithStorage<${spt}>(${name}, ${storage});',
                         storage=param.cpp_varname, spt=param.set_at, name=_encaps(param.name)))
 
                 if param.on_update is not None:
diff --git a/src/mongo/idl/server_parameter_with_storage.h b/src/mongo/idl/server_parameter_with_storage.h
index 9e3ec0960a3..962312e78b4 100644
--- a/src/mongo/idl/server_parameter_with_storage.h
+++ b/src/mongo/idl/server_parameter_with_storage.h
@@ -175,7 +175,7 @@ struct storage_wrapper {
 /**
  * Specialization of ServerParameter used by IDL generator.
  */
-template <typename T>
+template <ServerParameterType paramType, typename T>
 class IDLServerParameterWithStorage : public ServerParameter {
 private:
     using SPT = ServerParameterType;
@@ -185,14 +185,14 @@ public:
     static constexpr bool thread_safe = SW::thread_safe;
     using element_type = typename SW::type;
 
-    IDLServerParameterWithStorage(StringData name, T& storage, ServerParameterType paramType)
+    IDLServerParameterWithStorage(StringData name, T& storage)
         : ServerParameter(ServerParameterSet::getGlobal(),
                           name,
                           paramType == SPT::kStartupOnly || paramType == SPT::kStartupAndRuntime,
                           paramType == SPT::kRuntimeOnly || paramType == SPT::kStartupAndRuntime),
           _storage(storage) {
-        invariant(thread_safe || paramType == SPT::kStartupOnly,
-                  "Runtime server parameters must be thread safe");
+        static_assert(thread_safe || paramType == SPT::kStartupOnly,
+                      "Runtime server parameters must be thread safe");
     }
 
     /**
@@ -318,11 +318,10 @@ private:
 
 // MSVC has trouble resolving T=decltype(param) through the above class template.
 // Avoid that by using this proxy factory to infer storage type.
-template <typename T>
-IDLServerParameterWithStorage<T>* makeIDLServerParameterWithStorage(StringData name,
-                                                                    T& storage,
-                                                                    ServerParameterType spt) {
-    return new IDLServerParameterWithStorage<T>(name, storage, spt);
+template <ServerParameterType paramType, typename T>
+IDLServerParameterWithStorage<paramType, T>* makeIDLServerParameterWithStorage(StringData name,
+                                                                               T& storage) {
+    return new IDLServerParameterWithStorage<paramType, T>(name, storage);
 }
 
 }  // namespace mongo
diff --git a/src/mongo/idl/server_parameter_with_storage_test.cpp b/src/mongo/idl/server_parameter_with_storage_test.cpp
index b5965006be2..154fdfb210f 100644
--- a/src/mongo/idl/server_parameter_with_storage_test.cpp
+++ b/src/mongo/idl/server_parameter_with_storage_test.cpp
@@ -58,7 +58,7 @@ void doStorageTest(StringData name,
                    const std::vector<std::string>& valid,
                    const std::vector<std::string>& invalid) {
     T val;
-    IDLServerParameterWithStorage<T> param(name, val, spt);
+    IDLServerParameterWithStorage<spt, T> param(name, val);
     using element_type = typename decltype(param)::element_type;
 
     // Check type coersion.
@@ -162,7 +162,7 @@ TEST(ServerParameterWithStorage, BoundsTest) {
     using idl_server_parameter_detail::LT;
 
     int val;
-    IDLServerParameterWithStorage<int> param("BoundsTest", val, SPT::kStartupOnly);
+    IDLServerParameterWithStorage<SPT::kStartupOnly, int> param("BoundsTest", val);
 
     param.addBound<GT>(10);
     auto status = param.setFromString("5");