fixes envvar Option[T] decoder

confutils/envvar/envvar_serialization.nim

@@ -43,7 +43,7 @@ template loadFile*(_: type Envvar,
   var reader = unpackArgs(init, [EnvvarReader, prefix, params])
   reader.readValue(RecordType)
 
-template saveFile*(Format: type, prefix: string, value: auto, params: varargs[untyped]) =
+template saveFile*(_: type Envvar, prefix: string, value: auto, params: varargs[untyped]) =
   mixin init, WriterType, writeValue
 
   var writer = unpackArgs(init, [EnvvarWriter, prefix, params])

confutils/envvar/reader.nim

@@ -29,8 +29,6 @@ proc handleReadException*(r: EnvvarReader,
 proc init*(T: type EnvvarReader, prefix: string): T =
   result.prefix = prefix
 
-template getUnderlyingType*[T](_: Option[T]): untyped = T
-
 proc readValue*[T](r: var EnvvarReader, value: var T)
                   {.raises: [SerializationError, ValueError, Defect].} =
   mixin readValue
@@ -45,15 +43,14 @@ proc readValue*[T](r: var EnvvarReader, value: var T)
     getValue(key, value)
 
   elif T is Option:
+    template getUnderlyingType[T](_: Option[T]): untyped = T
     let key = constructKey(r.prefix, r.key)
     if existsEnv(key):
       type uType = getUnderlyingType(value)      
-      var outVal: uType
       when uType is string:
         value = some(os.getEnv(key))
       else:        
-        r.readValue(outVal)
+        value = some(r.readValue(uType))
-        value = some(outVal)
 
   elif T is (seq or array):
     when uTypeIsPrimitives(T):

tests/test_envvar.nim

@@ -88,5 +88,29 @@ proc testEncoder() =
       check x.antennae.isNone
       check x.bumper.get() == "Chromium"
 
+type
+  ValidIpAddress {.requiresInit.} = object
+    value: string
+
+  TestObject = object
+    address: Option[ValidIpAddress]
+
+proc readValue(r: var EnvvarReader, value: var ValidIpAddress) =
+  r.readValue(value.value)
+
+proc writeValue(w: var EnvvarWriter, value: ValidIpAddress) =
+  w.writeValue(value.value)
+
+proc testOptionalFields() =
+  suite "optional fields test suite":
+    test "optional field with requiresInit pragma":
+
+      var z = TestObject(address: some(ValidIpAddress(value: "1.2.3.4")))
+      Envvar.saveFile(commonPrefix, z)
+      var x = Envvar.loadFile(commonPrefix, TestObject)
+      check x.address.isSome
+      check x.address.get().value == "1.2.3.4"
+      
 testUtils()
 testEncoder()
+testOptionalFields()