fix(headers): Remove raw part when getting mutable reference to typed…

… header

If you get a mutable reference to a typed header it is possible to make
the two representations be out of sync. To avoid this, after parsing the
raw part it should be removed.

Fixes #821.

src/header/internals/item.rs

@@ -78,6 +78,9 @@ impl Item {
  Err(_) => ()
  }
  }
+ if self.raw.is_some() && self.typed.get_mut(tid).is_some() {
+ self.raw = OptCell::new(None);
+ }
  self.typed.get_mut(tid).map(|typed| unsafe { typed.downcast_mut_unchecked() })
  }
 }

src/header/mod.rs

@@ -670,6 +670,7 @@ mod tests {
  fn test_get_mutable() {
  let mut headers = Headers::from_raw(&raw!(b"Content-Length: 10")).unwrap();
  *headers.get_mut::<ContentLength>().unwrap() = ContentLength(20);
+ assert_eq!(headers.get_raw("content-length").unwrap(), &[b"20".to_vec()][..]);
  assert_eq!(*headers.get::<ContentLength>().unwrap(), ContentLength(20));
  }