add ErrorKind::DeserializeAnyNotSupported (#211)

Cargo.toml

@@ -2,6 +2,8 @@
 name = "bincode"
 version = "0.8.1"
 authors = ["Ty Overby <ty@pre-alpha.com>", "Francesco Mazzoli <f@mazzo.li>", "David Tolnay <dtolnay@gmail.com>", "Daniel Griffen"]
+
+# Adding ErrorKind::DeserializeAnyNotSupported is a breaking change
 publish = false
 
 repository = "https://github.com/TyOverby/bincode"

src/de/mod.rs

@@ -85,8 +85,7 @@ where R: BincodeRead<'de>, S: SizeLimit, E: ByteOrder {
     fn deserialize_any<V>(self, _visitor: V) -> Result<V::Value>
         where V: serde::de::Visitor<'de>,
     {
-        let message = "bincode does not support Deserializer::deserialize_any";
-        Err(Error::custom(message))
+        Err(Box::new(ErrorKind::DeserializeAnyNotSupported))
     }
 
     fn deserialize_bool<V>(self, visitor: V) -> Result<V::Value>

src/internal.rs

@@ -41,6 +41,9 @@ pub enum ErrorKind {
         #[allow(missing_docs)]
         detail: Option<String>
     },
+    /// Serde has a deserialize_any method that lets the format hint to the
+    /// object which route to take in deserializing.
+    DeserializeAnyNotSupported,
     /// If (de)serializing a message takes more than the provided size limit, this
     /// error is returned.
     SizeLimit,
@@ -56,6 +59,7 @@ impl error::Error for ErrorKind {
             ErrorKind::Io(ref err) => error::Error::description(err),
             ErrorKind::InvalidEncoding{desc, ..} => desc,
             ErrorKind::SequenceMustHaveLength => "bincode can't encode infinite sequences",
+            ErrorKind::DeserializeAnyNotSupported => "bincode doesn't support serde::Deserializer::deserialize_any",
             ErrorKind::SizeLimit => "the size limit for decoding has been reached",
             ErrorKind::Custom(ref msg) => msg,
 
@@ -67,6 +71,7 @@ impl error::Error for ErrorKind {
             ErrorKind::Io(ref err) => Some(err),
             ErrorKind::InvalidEncoding{..} => None,
             ErrorKind::SequenceMustHaveLength => None,
+            ErrorKind::DeserializeAnyNotSupported => None,
             ErrorKind::SizeLimit => None,
             ErrorKind::Custom(_) => None,
         }
@@ -92,6 +97,8 @@ impl fmt::Display for ErrorKind {
                 write!(fmt, "bincode can only encode sequences and maps that have a knowable size ahead of time."),
             ErrorKind::SizeLimit =>
                 write!(fmt, "size limit was exceeded"),
+            ErrorKind::DeserializeAnyNotSupported=>
+                write!(fmt, "bincode does not support the serde::Deserializer::deserialize_any method"),
             ErrorKind::Custom(ref s) =>
                 s.fmt(fmt),
         }