fix nim devel error: 'result' requires explicit initialization

.gitignore

@@ -3,5 +3,6 @@ tests/test_all
 nimble.develop
 nimble.paths
 build/
+vendor/
 
 *.exe

serialization.nim

@@ -26,6 +26,8 @@ template encode*(Format: type, value: auto, params: varargs[untyped]): auto =
 {.push warning[ProveInit]: off.}
 proc readValue*(reader: var auto, T: type): T =
   mixin readValue
+  when (NimMajor, NimMinor) > (1, 6):
+    result = default(T)
   reader.readValue(result)
 {.pop.}
 

tests/test_all.nim

@@ -1,3 +1,4 @@
 import
-  test_object_serialization
+  test_object_serialization,
+  test_reader
 

tests/test_reader.nim

@@ -0,0 +1,29 @@
+import
+  unittest2,
+  ../serialization
+
+{.used.}
+
+type
+  TestObj = object
+    number: int
+
+  XyzReader = object
+
+proc readValue(r: XyzReader, val: var TestObj) =
+  val.number = 13
+
+proc init(T: type XyzReader, stream: InputStream): T =
+  XyzReader()
+
+serializationFormat Xyz
+Xyz.setReader XyzReader
+
+suite "object serialization":
+  test "readValue":
+    let z = Xyz.decode("", TestObj)
+    check z.number == 13
+    
+    var r: XyzReader
+    let x = r.readValue(TestObj)
+    check x.number == 13