SERVER-44119 Customize string coersion for IDL

(cherry picked from commit 39bfc190446acd0b049c5cb29dfbbc6574a40ce1)

3 files changed, 31 insertions, 0 deletions

diff --git a/src/mongo/idl/server_parameter.cpp b/src/mongo/idl/server_parameter.cpp
index 5e0d3ef66fd..975f2b515e6 100644
--- a/src/mongo/idl/server_parameter.cpp
+++ b/src/mongo/idl/server_parameter.cpp
@@ -88,6 +88,31 @@ void ServerParameterSet::add(ServerParameter* sp) {
     x = sp;
 }
 
+StatusWith<std::string> ServerParameter::coerceToString(const BSONElement& element, bool redact) {
+    switch (element.type()) {
+        case NumberDouble:
+            return std::to_string(element.Double());
+        case String:
+            return element.String();
+        case NumberInt:
+            return std::to_string(element.Int());
+        case NumberLong:
+            return std::to_string(element.Long());
+        case Date:
+            return dateToISOStringLocal(element.Date());
+        default:
+            std::string diag;
+            if (redact) {
+                diag = "###";
+            } else {
+                diag = element.toString();
+            }
+            return {ErrorCodes::BadValue,
+                    str::stream() << "Unsupported type " << typeName(element.type()) << " (value: '"
+                                  << diag << "') for setParameter: " << name()};
+    }
+}
+
 IDLServerParameterDeprecatedAlias::IDLServerParameterDeprecatedAlias(StringData name,
                                                                      ServerParameter* sp)
     : ServerParameter(ServerParameterSet::getGlobal(),
diff --git a/src/mongo/idl/server_parameter.h b/src/mongo/idl/server_parameter.h
index f4f32265ce7..4fa5ba6b6f7 100644
--- a/src/mongo/idl/server_parameter.h
+++ b/src/mongo/idl/server_parameter.h
@@ -122,6 +122,10 @@ public:
         _testOnly = true;
     }
 
+protected:
+    // Helper for translating setParameter values from BSON to string.
+    StatusWith<std::string> coerceToString(const BSONElement&, bool redact);
+
 private:
     std::string _name;
     bool _allowedToChangeAtStartup;
diff --git a/src/mongo/idl/server_parameter_specialized_test.cpp b/src/mongo/idl/server_parameter_specialized_test.cpp
index 5587e29fad9..80a3d02b5a5 100644
--- a/src/mongo/idl/server_parameter_specialized_test.cpp
+++ b/src/mongo/idl/server_parameter_specialized_test.cpp
@@ -211,6 +211,8 @@ TEST(SpecializedServerParameter, withAtomicValue) {
     auto* wv = getServerParameter<cls>("specializedWithAtomicValue");
     ASSERT_EQ(wv->_data.load(), cls::kDataDefault);
     ASSERT_APPENDED_INT(wv, cls::kDataDefault);
+    ASSERT_OK(wv->set(BSON("" << 99).firstElement()));
+    ASSERT_APPENDED_INT(wv, 99);
     ASSERT_OK(wv->setFromString("101"));
     ASSERT_APPENDED_INT(wv, 101);
     ASSERT_EQ(wv->_data.load(), 101);