Fix bug with .proto without messages (again), and add a test case for it.

generator/nanopb_generator.py

@@ -414,6 +414,7 @@ def generate_header(dependencies, headername, enums, messages):
     for msg in messages:
         yield msg.fields_declaration() + '\n'
     
+    if messages:
         count_required_fields = lambda m: len([f for f in msg.fields if f.htype == 'PB_HTYPE_REQUIRED'])
         largest_msg = max(messages, key = count_required_fields)
         largest_count = count_required_fields(largest_msg)

tests/Makefile

@@ -1,7 +1,7 @@
 CFLAGS=-ansi -Wall -Werror -I .. -g -O0 --coverage
 LDFLAGS=--coverage
 DEPS=../pb_decode.h ../pb_encode.h ../pb.h person.pb.h callbacks.pb.h unittests.h unittestproto.pb.h alltypes.pb.h missing_fields.pb.h
-TESTS=test_decode1 test_encode1 decode_unittests encode_unittests
+TESTS=test_decode1 test_encode1 decode_unittests encode_unittests test_no_messages
 
 all: breakpoints $(TESTS) run_unittests
 
@@ -28,6 +28,7 @@ test_encode_callbacks: test_encode_callbacks.o pb_encode.o callbacks.pb.o
 test_missing_fields: test_missing_fields.o pb_encode.o pb_decode.o missing_fields.pb.o
 decode_unittests: decode_unittests.o pb_decode.o unittestproto.pb.o
 encode_unittests: encode_unittests.o pb_encode.o unittestproto.pb.o
+test_no_messages: no_messages.pb.h no_messages.pb.c no_messages.pb.o
 
 %.pb: %.proto
 	protoc -I. -I../generator -I/usr/include -o$@ $<

tests/no_messages.proto

@@ -0,0 +1,7 @@
+/* Test that a file without any messages works. */
+
+enum Test {
+    First = 1;
+}
+
+