decode ERR lines as actual errors

Author: Byron

git-protocol/src/packet_line/decode.rs

@@ -1,4 +1,4 @@
-use crate::packet_line::{self, FLUSH_LINE, MAX_DATA_LEN, MAX_LINE_LEN, U16_HEX_BYTES};
+use crate::packet_line::{self, ERR_PREFIX, FLUSH_LINE, MAX_DATA_LEN, MAX_LINE_LEN, U16_HEX_BYTES};
 use bstr::BString;
 use quick_error::quick_error;
 
@@ -16,7 +16,7 @@ quick_error! {
         DataIsEmpty {
             display("Received an invalid empty line")
         }
-        Line(data: BString) {
+        Line(data: BString, bytes_consumed: usize) {
             display("{}", data)
         }
     }
@@ -65,11 +65,15 @@ pub fn streaming(data: &[u8]) -> Result<Stream, Error> {
         return Err(Error::DataIsEmpty);
     }
 
-    // todo: error line
     let mut data = &data[U16_HEX_BYTES..wanted_bytes];
     if data[data.len() - 1] == b'\n' {
         data = &data[..data.len() - 1];
     }
+
+    if data.len() >= ERR_PREFIX.len() && &data[..ERR_PREFIX.len()] == ERR_PREFIX {
+        return Err(Error::Line(data[ERR_PREFIX.len()..].into(), wanted_bytes));
+    }
+
     Ok(Stream::Complete {
         line: packet_line::Borrowed::Data(data),
         bytes_consumed: wanted_bytes,

git-protocol/src/packet_line/mod.rs

@@ -5,6 +5,7 @@ pub(crate) const U16_HEX_BYTES: usize = 4;
 pub(crate) const MAX_DATA_LEN: usize = 65516;
 pub(crate) const MAX_LINE_LEN: usize = MAX_DATA_LEN + U16_HEX_BYTES;
 pub(crate) const FLUSH_LINE: &[u8] = b"0000";
+pub(crate) const ERR_PREFIX: &[u8] = b"ERR ";
 
 #[derive(PartialEq, Eq, Debug, Hash, Ord, PartialOrd, Clone, Copy)]
 #[cfg_attr(feature = "serde1", derive(serde::Serialize, serde::Deserialize))]

git-protocol/tests/packet_line/decode.rs

@@ -30,6 +30,11 @@ mod streaming {
         assert_complete(streaming(b"0006a\n"), 6, PacketLine::Data(b"a"))
     }
 
+    #[test]
+    fn ignore_extra_bytes() -> crate::Result {
+        assert_complete(streaming(b"0006a\nhello"), 6, PacketLine::Data(b"a"))
+    }
+
     #[test]
     fn error_on_oversized_line() {
         assert_err_display(
@@ -38,6 +43,14 @@ mod streaming {
         );
     }
 
+    #[test]
+    fn error_on_error_line() {
+        assert_err_display(
+            streaming(b"0011ERR the error-and just ignored because not part of the size"),
+            "the error",
+        );
+    }
+
     #[test]
     fn error_on_invalid_hex() {
         assert_err_display(