From 4f4a3dfb1a2a46021bc47f19bca48b0c4df94dd5 Mon Sep 17 00:00:00 2001
From: Jonas Hietala <tradet.h@gmail.com>
Date: Tue, 9 Sep 2014 07:28:59 +0200
Subject: [PATCH] Decoding json now defaults Option<_> to None.
Closes #12794
---
src/libserialize/json.rs | 38 +++++++++++++++++++++++++++++++++++++-
1 file changed, 37 insertions(+), 1 deletion(-)
diff --git a/src/libserialize/json.rs b/src/libserialize/json.rs
index b29200597aa..733bc593922 100644
--- a/src/libserialize/json.rs
+++ b/src/libserialize/json.rs
@@ -2128,7 +2128,15 @@ impl ::Decoder<DecoderError> for Decoder {
let mut obj = try!(expect!(self.pop(), Object));
let value = match obj.pop(&name.to_string()) {
- None => return Err(MissingFieldError(name.to_string())),
+ None => {
+ // Add a Null and try to parse it as an Option<_>
+ // to get None as a default value.
+ self.stack.push(Null);
+ match f(self) {
+ Ok(x) => x,
+ Err(_) => return Err(MissingFieldError(name.to_string())),
+ }
+ },
Some(json) => {
self.stack.push(json);
try!(f(self))
@@ -2167,6 +2175,7 @@ impl ::Decoder<DecoderError> for Decoder {
}
fn read_option<T>(&mut self, f: |&mut Decoder, bool| -> DecodeResult<T>) -> DecodeResult<T> {
+ debug!("read_option()");
match self.pop() {
Null => f(self, false),
value => { self.stack.push(value); f(self, true) }
@@ -2372,6 +2381,33 @@ mod tests {
use std::{i64, u64, f32, f64, io};
use std::collections::TreeMap;
+ #[deriving(Decodable, Eq, PartialEq, Show)]
+ struct OptionData {
+ opt: Option<uint>,
+ }
+
+ #[test]
+ fn test_decode_option_none() {
+ let s ="{}";
+ let obj: OptionData = super::decode(s).unwrap();
+ assert_eq!(obj, OptionData { opt: None });
+ }
+
+ #[test]
+ fn test_decode_option_some() {
+ let s = "{ \"opt\": 10 }";
+ let obj: OptionData = super::decode(s).unwrap();
+ assert_eq!(obj, OptionData { opt: Some(10u) });
+ }
+
+ #[test]
+ fn test_decode_option_malformed() {
+ check_err::<OptionData>("{ \"opt\": [] }",
+ ExpectedError("Number".to_string(), "[]".to_string()));
+ check_err::<OptionData>("{ \"opt\": false }",
+ ExpectedError("Number".to_string(), "false".to_string()));
+ }
+
#[deriving(PartialEq, Encodable, Decodable, Show)]
enum Animal {
Dog,