Fix empty submessages getting encoded in proto3 mode (#395)

Repeated callback fields were being treated as "always present",
even if the callback pointer wasn't set.

5 files changed, 92 insertions, 1 deletions

diff --git a/pb_encode.c b/pb_encode.c
index 4dd53a9..0f89d98 100644
--- a/pb_encode.c
+++ b/pb_encode.c
@@ -249,7 +249,7 @@ static bool pb_check_proto3_default_value(const pb_field_t *field, const void *p
         /* Repeated fields inside proto3 submessage: present if count != 0 */
         if (field->size_offset != 0)
             return *(const pb_size_t*)pSize == 0;
-        else
+        else if (PB_ATYPE(type) == PB_ATYPE_STATIC)
             return false; /* Fixed length array */
     }
     else if (PB_HTYPE(type) == PB_HTYPE_ONEOF)
diff --git a/tests/regression/issue_395/SConscript b/tests/regression/issue_395/SConscript
new file mode 100644
index 0000000..8bc1030
--- /dev/null
+++ b/tests/regression/issue_395/SConscript
@@ -0,0 +1,14 @@
+# Regression test for #395:
+# Unexpected empty submessage in proto3 mode
+
+Import("env")
+
+env.NanopbProto(["test.proto", "test.options"])
+testprog = env.Program(["test.c",
+                 "test.pb.c",
+                 "$COMMON/pb_encode.o",
+                 "$COMMON/pb_decode.o",
+                 "$COMMON/pb_common.o"])
+
+env.RunTest(testprog)
+
diff --git a/tests/regression/issue_395/test.c b/tests/regression/issue_395/test.c
new file mode 100644
index 0000000..9578caf
--- /dev/null
+++ b/tests/regression/issue_395/test.c
@@ -0,0 +1,38 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <pb_encode.h>
+#include <pb_decode.h>
+#include "test.pb.h"
+#include "unittests.h"
+
+int main(int argc, char **argv)
+{
+    int status = 0;
+    uint8_t buffer[512] = {0};
+    int i;
+    pb_ostream_t ostream;
+    
+    Reply reply = Reply_init_zero;
+    Reply_Result request_result = Reply_Result_OK;
+
+    ostream = pb_ostream_from_buffer(buffer, sizeof(buffer));
+    reply.result = request_result;
+    if (!pb_encode(&ostream, Reply_fields, &reply)) {
+        fprintf(stderr, "Encode failed: %s\n", PB_GET_ERROR(&ostream));
+        return 1;
+    }
+
+    printf("response payload (%d):", (int)ostream.bytes_written);
+    for (i = 0; i < ostream.bytes_written; i++) {
+        printf("%02X", buffer[i]);
+    }
+    printf("\n");
+
+    TEST(ostream.bytes_written == 2);
+    TEST(buffer[0] == 0x08);
+    TEST(buffer[1] == 0x01);
+    
+    return status;
+}
+
diff --git a/tests/regression/issue_395/test.options b/tests/regression/issue_395/test.options
new file mode 100644
index 0000000..5594796
--- /dev/null
+++ b/tests/regression/issue_395/test.options
@@ -0,0 +1,2 @@
+SubSubAMessage.somestring max_size:64
+SubSubBMessage.somestring max_size:64
diff --git a/tests/regression/issue_395/test.proto b/tests/regression/issue_395/test.proto
new file mode 100644
index 0000000..91bf371
--- /dev/null
+++ b/tests/regression/issue_395/test.proto
@@ -0,0 +1,37 @@
+syntax = "proto3";
+
+message Error
+{
+    int32 code = 1;
+    string message = 2;
+}
+
+message SubSubAMessage
+{
+    string somestring = 1;
+}
+
+message SubSubBMessage
+{
+    string somestring = 1;
+}
+
+message SubMessage
+{
+    SubSubAMessage subsubmessageA = 1;
+    repeated SubSubBMessage subsubmessageB = 2;
+}
+
+message Reply
+{
+    enum Result
+    {
+        ERROR = 0;
+        OK = 1;
+        SOME_A = 2;
+    }
+
+    Result result = 1;
+    Error error = 2;
+    SubMessage submessage = 3;
+}