Auto merge of #421 - serde-rs:length, r=oli-obk

Invalid-length when enum seq is too short

Fixes https://github.com/serde-rs/json/issues/96.

serde_codegen/src/de.rs

@@ -395,6 +395,7 @@ fn deserialize_seq(
     fields: &[Field],
     is_struct: bool,
 ) -> P<ast::Expr> {
+    let mut index_in_seq = 0usize;
     let let_values: Vec<_> = fields.iter()
         .enumerate()
         .map(|(i, field)| {
@@ -420,14 +421,16 @@ fn deserialize_seq(
                         })
                     }
                 };
-                quote_stmt!(cx,
+                let assign = quote_stmt!(cx,
                     let $name = match $visit {
                         Some(value) => { value },
                         None => {
-                            return Err(_serde::de::Error::end_of_stream());
+                            return Err(_serde::de::Error::invalid_length($index_in_seq));
                         }
                     };
-                ).unwrap()
+                ).unwrap();
+                index_in_seq += 1;
+                assign
             }
         })
         .collect();

testing/tests/test_annotations.rs

@@ -946,3 +946,31 @@ fn test_missing_renamed_field_enum() {
         Error::MissingField("d"),
     );
 }
+
+#[derive(Debug, PartialEq, Deserialize)]
+enum InvalidLengthEnum {
+    A(i32, i32, i32),
+    B(#[serde(skip_deserializing)] i32, i32, i32),
+}
+
+#[test]
+fn test_invalid_length_enum() {
+    assert_de_tokens_error::<InvalidLengthEnum>(
+        &[
+            Token::EnumSeqStart("InvalidLengthEnum", "A", Some(3)),
+                Token::EnumSeqSep,
+                Token::I32(1),
+            Token::EnumSeqEnd,
+        ],
+        Error::InvalidLength(1),
+    );
+    assert_de_tokens_error::<InvalidLengthEnum>(
+        &[
+            Token::EnumSeqStart("InvalidLengthEnum", "B", Some(3)),
+                Token::EnumSeqSep,
+                Token::I32(1),
+            Token::EnumSeqEnd,
+        ],
+        Error::InvalidLength(1),
+    );
+}