Allowed optional entry checks.

src/message.rs

@@ -1109,16 +1109,20 @@ impl FieldSetting {
         &self.default_setting
     }
 
-    fn check(&self, value: &Field) -> Result<Field, MTTError> {
+    fn check(&self, value: Option<Field>) -> Result<Field, MTTError> {
-        let output = value.clone();
+        match value {
-        let vft: FieldType = value.into();
+            Some(data) => {
+                let vft: FieldType = (&data).into();
                 if vft != self.fieldtype {
                     return Err(MTTError::DocumentFieldWrongDataType(
                         self.fieldtype.clone(),
                         vft,
                     ));
                 }
-        Ok(output)
+                Ok(data.clone())
+            }
+            None => Err(MTTError::DocumentFieldMissing("".to_string())),
+        }
     }
 }
 
@@ -1130,7 +1134,7 @@ mod fieldsettings {
     fn checks_field_type() {
         let fset = FieldSetting::new(FieldType::Uuid);
         let value: Field = Uuid::new_v4().into();
-        match fset.check(&value) {
+        match fset.check(Some(value.clone())) {
             Ok(data) => assert_eq!(data, value),
             Err(err) => unreachable!("got {:?}: should have gotten a value", err),
         }
@@ -1140,7 +1144,7 @@ mod fieldsettings {
     fn checks_for_bad_field_type() {
         let fset = FieldSetting::new(FieldType::Uuid);
         let value: Field = "text".into();
-        match fset.check(&value) {
+        match fset.check(Some(value)) {
             Ok(data) => unreachable!("got {:?}: should have gotten an error", data),
             Err(err) => match err {
                 MTTError::DocumentFieldWrongDataType(expected, got) => {
@@ -1152,6 +1156,18 @@ mod fieldsettings {
         }
     }
 
+    #[test]
+    fn no_default_returns_error() {
+        let fset = FieldSetting::new(FieldType::Uuid);
+        match fset.check(None) {
+            Ok(data) => unreachable!("got {:?}: should have gotten an error", data),
+            Err(err) => match err {
+                MTTError::DocumentFieldMissing(data) => assert_eq!(data, ""),
+                _ => unreachable!("got {:?}: should have gotten a value", err),
+            },
+        }
+    }
+
     #[test]
     fn can_field_type_be_assigned() {
         let ftypes = [FieldType::StaticString, FieldType::Uuid];
@@ -1820,7 +1836,7 @@ impl DocumentFile {
             let doc = self.docs.get_mut(oid).unwrap();
             for (key, value) in update.get_values().iter() {
                 match self.docdef.get_field(key) {
-                    Ok(fset) => match fset.check(value) {
+                    Ok(fset) => match fset.check(Some(value.clone())) {
                         Ok(field) => doc.add_field(key.clone(), field.clone()),
                         Err(err) => return err.into(),
                     },