Improve the detection of missing required fields.

Now the limit of tracked fields is configurable at compile-time using
PB_MAX_REQUIRED_FIELDS. Added related test and updated documentation.

Fixes issue #18.

3 files changed, 192 insertions, 2 deletions

diff --git a/tests/Makefile b/tests/Makefile
index 8e2df140..24e9ba62 100644
--- a/tests/Makefile
+++ b/tests/Makefile
@@ -1,6 +1,6 @@
 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
+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
 
 all: breakpoints $(TESTS) run_unittests
@@ -25,6 +25,7 @@ test_encode2: test_encode2.o pb_encode.o person.pb.o
 test_encode3: test_encode3.o pb_encode.o alltypes.pb.o
 test_decode_callbacks: test_decode_callbacks.o pb_decode.o callbacks.pb.o
 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
 
@@ -41,7 +42,7 @@ coverage: run_unittests
 	gcov pb_encode.gcda
 	gcov pb_decode.gcda
 
-run_unittests: decode_unittests encode_unittests test_encode1 test_encode2 test_encode3 test_decode1 test_decode2 test_decode3 test_encode_callbacks test_decode_callbacks
+run_unittests: decode_unittests encode_unittests test_encode1 test_encode2 test_encode3 test_decode1 test_decode2 test_decode3 test_encode_callbacks test_decode_callbacks test_missing_fields
 	rm -f *.gcda
 	
 	./decode_unittests > /dev/null
@@ -61,6 +62,8 @@ run_unittests: decode_unittests encode_unittests test_encode1 test_encode2 test_
 
 	./test_encode3 | ./test_decode3
 	./test_encode3 | protoc --decode=AllTypes -I. -I../generator -I/usr/include alltypes.proto >/dev/null
+	
+	./test_missing_fields
 
 run_fuzztest: test_decode2
 	bash -c 'I=1; while true; do cat /dev/urandom | ./test_decode2 > /dev/null; I=$$(($$I+1)); echo -en "\r$$I"; done'
diff --git a/tests/missing_fields.proto b/tests/missing_fields.proto
new file mode 100644
index 00000000..cbb23ba1
--- /dev/null
+++ b/tests/missing_fields.proto
@@ -0,0 +1,138 @@
+/* Test for one missing field among many */
+
+message AllFields
+{
+    required int32 field1 = 1;
+    required int32 field2 = 2;
+    required int32 field3 = 3;
+    required int32 field4 = 4;
+    required int32 field5 = 5;
+    required int32 field6 = 6;
+    required int32 field7 = 7;
+    required int32 field8 = 8;
+    required int32 field9 = 9;
+    required int32 field10 = 10;
+    required int32 field11 = 11;
+    required int32 field12 = 12;
+    required int32 field13 = 13;
+    required int32 field14 = 14;
+    required int32 field15 = 15;
+    required int32 field16 = 16;
+    required int32 field17 = 17;
+    required int32 field18 = 18;
+    required int32 field19 = 19;
+    required int32 field20 = 20;
+    required int32 field21 = 21;
+    required int32 field22 = 22;
+    required int32 field23 = 23;
+    required int32 field24 = 24;
+    required int32 field25 = 25;
+    required int32 field26 = 26;
+    required int32 field27 = 27;
+    required int32 field28 = 28;
+    required int32 field29 = 29;
+    required int32 field30 = 30;
+    required int32 field31 = 31;
+    required int32 field32 = 32;
+    required int32 field33 = 33;
+    required int32 field34 = 34;
+    required int32 field35 = 35;
+    required int32 field36 = 36;
+    required int32 field37 = 37;
+    required int32 field38 = 38;
+    required int32 field39 = 39;
+    required int32 field40 = 40;
+    required int32 field41 = 41;
+    required int32 field42 = 42;
+    required int32 field43 = 43;
+    required int32 field44 = 44;
+    required int32 field45 = 45;
+    required int32 field46 = 46;
+    required int32 field47 = 47;
+    required int32 field48 = 48;
+    required int32 field49 = 49;
+    required int32 field50 = 50;
+    required int32 field51 = 51;
+    required int32 field52 = 52;
+    required int32 field53 = 53;
+    required int32 field54 = 54;
+    required int32 field55 = 55;
+    required int32 field56 = 56;
+    required int32 field57 = 57;
+    required int32 field58 = 58;
+    required int32 field59 = 59;
+    required int32 field60 = 60;
+    required int32 field61 = 61;
+    required int32 field62 = 62;
+    required int32 field63 = 63;
+    required int32 field64 = 64;
+}
+
+message MissingField
+{
+    required int32 field1 = 1;
+    required int32 field2 = 2;
+    required int32 field3 = 3;
+    required int32 field4 = 4;
+    required int32 field5 = 5;
+    required int32 field6 = 6;
+    required int32 field7 = 7;
+    required int32 field8 = 8;
+    required int32 field9 = 9;
+    required int32 field10 = 10;
+    required int32 field11 = 11;
+    required int32 field12 = 12;
+    required int32 field13 = 13;
+    required int32 field14 = 14;
+    required int32 field15 = 15;
+    required int32 field16 = 16;
+    required int32 field17 = 17;
+    required int32 field18 = 18;
+    required int32 field19 = 19;
+    required int32 field20 = 20;
+    required int32 field21 = 21;
+    required int32 field22 = 22;
+    required int32 field23 = 23;
+    required int32 field24 = 24;
+    required int32 field25 = 25;
+    required int32 field26 = 26;
+    required int32 field27 = 27;
+    required int32 field28 = 28;
+    required int32 field29 = 29;
+    required int32 field30 = 30;
+    required int32 field31 = 31;
+    required int32 field32 = 32;
+    required int32 field33 = 33;
+    required int32 field34 = 34;
+    required int32 field35 = 35;
+    required int32 field36 = 36;
+    required int32 field37 = 37;
+    required int32 field38 = 38;
+    required int32 field39 = 39;
+    required int32 field40 = 40;
+    required int32 field41 = 41;
+    required int32 field42 = 42;
+    required int32 field43 = 43;
+    required int32 field44 = 44;
+    required int32 field45 = 45;
+    required int32 field46 = 46;
+    required int32 field47 = 47;
+    required int32 field48 = 48;
+    required int32 field49 = 49;
+    required int32 field50 = 50;
+    required int32 field51 = 51;
+    required int32 field52 = 52;
+    required int32 field53 = 53;
+    required int32 field54 = 54;
+    required int32 field55 = 55;
+    required int32 field56 = 56;
+    required int32 field57 = 57;
+    required int32 field58 = 58;
+    required int32 field59 = 59;
+    required int32 field60 = 60;
+    required int32 field61 = 61;
+    required int32 field62 = 62;
+/*    required int32 field63 = 63; */
+    required int32 field64 = 64;
+}
+
diff --git a/tests/test_missing_fields.c b/tests/test_missing_fields.c
new file mode 100644
index 00000000..46cd7d96
--- /dev/null
+++ b/tests/test_missing_fields.c
@@ -0,0 +1,49 @@
+/* Checks that missing required fields are detected properly */
+
+#include <stdio.h>
+#include <pb_encode.h>
+#include <pb_decode.h>
+#include "missing_fields.pb.h"
+
+int main()
+{
+    uint8_t buffer[512] = {};
+    
+    /* Create a message with one missing field */
+    {
+        MissingField msg = {};
+        pb_ostream_t stream = pb_ostream_from_buffer(buffer, sizeof(buffer));
+        if (!pb_encode(&stream, MissingField_fields, &msg))
+        {
+            printf("Encode failed.\n");
+            return 1;
+        }
+    }
+
+    /* Test that it decodes properly if we don't require that field */
+    {
+        MissingField msg = {};
+        pb_istream_t stream = pb_istream_from_buffer(buffer, sizeof(buffer));
+        
+        if (!pb_decode(&stream, MissingField_fields, &msg))
+        {
+            printf("Decode failed.\n");
+            return 2;
+        }
+    }
+    
+    /* Test that it does *not* decode properly if we require the field */
+    {
+        AllFields msg = {};
+        pb_istream_t stream = pb_istream_from_buffer(buffer, sizeof(buffer));
+        
+        if (pb_decode(&stream, AllFields_fields, &msg))
+        {
+            printf("Decode didn't detect missing field.\n");
+            return 3;
+        }
+    }
+    
+    return 0; /* All ok */
+}
+