Fix compute_size(value: &i32) for negative values

protobuf-test/src/common/v2/test_map_simple.rs

@@ -22,6 +22,19 @@ fn test_map() {
     test_serialize_deserialize_no_hex(&map);
 }
 
+#[test]
+fn test_map_negative_int() {
+    let mut map = TestMap::new();
+    let mut entry = TestMapEntry::new();
+    entry.set_v(10);
+
+    test_serialize_deserialize("", &map);
+
+    map.mut_m().insert("two".to_owned(), -2);
+    test_serialize_deserialize("0a 10 0a 03 74 77 6f 10 fe ff ff ff ff ff ff ff ff 01", &map);
+}
+
+
 #[test]
 fn test_map_with_object() {
     let mut map = TestMap::new();

protobuf-test/src/common/v2/test_map_simple_pb.proto

@@ -5,7 +5,7 @@ option (rustproto.generate_accessors_all) = true;
 
 
 message TestMap {
-    map<string, uint32> m = 1;
+    map<string, int32> m = 1;
     map<string, TestMapEntry> mm = 2;
 }
 

protobuf/src/reflect/types.rs

@@ -222,6 +222,10 @@ impl ProtobufType for ProtobufTypeInt32 {
     }
 
     fn compute_size(value: &i32) -> u32 {
+        // See also: https://github.com/protocolbuffers/protobuf/blob/bd00671b924310c0353a730bf8fa77c44e0a9c72/src/google/protobuf/io/coded_stream.h#L1300-L1306
+        if *value < 0 {
+            return 10
+        }
         rt::compute_raw_varint32_size(*value as u32)
     }
 

protobuf/src/stream.rs

@@ -790,14 +790,14 @@ impl<'a> CodedOutputStream<'a> {
                 self.position = 0;
             },
             OutputTarget::Bytes => {
-                panic!("refresh_buffer must not be called on CodedOutputStream create from slice");
+                panic!("refresh_buffer must not be called on CodedOutputStream created from slice");
             }
         }
         Ok(())
     }
 
     /// Flush to buffer to the underlying buffer.
-    /// Note that `CodedOutputStream` does `flush` in the descructor,
+    /// Note that `CodedOutputStream` does `flush` in the destructor,
     /// however, if `flush` in desctructor fails, then destructor panics
     /// and program terminates. So it's advisable to explicitly call flush
     /// before destructor.