The dotted path setter should now work properly.

lib/config.proto

@@ -28,8 +28,6 @@ message FileEncoding {
 }
 
 message Config {
-	optional string thing = 1 [(help) = "this is some help", (parameter) = "-q", (parameter) = "--q"];
-
 	repeated DiskEncoding disk = 2;
 	optional FileEncoding file = 3;
 	optional Decoder decoder = 4 [(help) = "Options for the flux decoder process"];

lib/proto.cc

@@ -48,7 +48,20 @@ void setProtoByString(google::protobuf::Message* message, const std::string& pat
 			Error() << fmt::format("config field '{}' in '{}' is not a message", item, path);
 
 		const auto* reflection = message->GetReflection();
-		message = reflection->MutableMessage(message, field);
+		switch (field->label())
+		{
+			case google::protobuf::FieldDescriptor::LABEL_OPTIONAL:
+				message = reflection->MutableMessage(message, field);
+				break;
+
+			case google::protobuf::FieldDescriptor::LABEL_REPEATED:
+				if (reflection->FieldSize(*message, field) == 0)
+					message = reflection->AddMessage(message, field);
+				else
+					message = reflection->MutableRepeatedMessage(message, field, 0);
+				break;
+		}
+
 		descriptor = message->GetDescriptor();
     }
 

mkninja.sh

@@ -172,12 +172,14 @@ runtest() {
     shift
 
     buildlibrary lib$prog.a \
+        -Idep/snowhouse/include \
         "$@"
 
     buildprogram $OBJDIR/$prog \
         lib$prog.a \
         libbackend.a \
         libproto.a \
+        libtestproto.a \
         libagg.a \
         libfmt.a
 
@@ -334,6 +336,9 @@ buildsimpleprogram brother240tool \
     libemu.a \
     libfmt.a \
 
+buildproto libtestproto.a \
+    tests/testproto.proto \
+
 runtest agg-test            tests/agg.cc
 runtest amiga-test          tests/amiga.cc
 runtest bitaccumulator-test tests/bitaccumulator.cc

tests/proto.cc

@@ -1,25 +1,35 @@
 #include "globals.h"
 #include "bytes.h"
-#include "lib/config.pb.h"
+#include "tests/testproto.pb.h"
 #include "proto.h"
+#include "snowhouse/snowhouse.h"
 #include <google/protobuf/text_format.h>
 #include <assert.h>
 #include <regex>
 
-static void test_proto(void)
+using namespace snowhouse;
+
+static void test_setting(void)
 {
-	Config config;
-	setProtoByString(&config, "file.filename", "foo");
+	TestProto config;
+	setProtoByString(&config, "i64", "-1");
+	setProtoByString(&config, "i32", "-2");
+	setProtoByString(&config, "u64", "3");
+	setProtoByString(&config, "u32", "4");
+	setProtoByString(&config, "d", "5.5");
+	setProtoByString(&config, "m.s", "string");
+	setProtoByString(&config, "r.s", "val1");
+	setProtoByString(&config, "r.s", "val2");
 
 	std::string s;
 	google::protobuf::TextFormat::PrintToString(config, &s);
 	s = std::regex_replace(s, std::regex("[ \t\n]+"), " ");
-	assert(s == "file { filename: \"foo\" } ");
+	AssertThat(s, Equals("i64: -1 i32: -2 u64: 3 u32: 4 d: 5.5 m { s: \"string\" } r { s: \"val2\" } "));
 }
 
 int main(int argc, const char* argv[])
 {
-	test_proto();
+	test_setting();
     return 0;
 }
 

tests/testproto.proto

@@ -0,0 +1,16 @@
+syntax = "proto2";
+
+message TestProto {
+	message SubMessage {
+		optional string s = 1;
+	}
+
+	optional int64 i64 = 1;
+	optional int32 i32 = 2;
+	optional uint64 u64 = 3;
+	optional uint32 u32 = 4;
+	optional double d = 5;
+	optional SubMessage m = 6;
+	repeated SubMessage r = 7;
+}
+