[clone] Don't expose hex-error in public interfaces anymore

That's usually a chose unless we also re-export these crates.
And that we just avoid for now as I have a feeling we can gain
some speed by leveraging the lower-case garantuee offered by git.
And even if not, we can be less abstract than what 'hex' does.

git-object/src/owned/id.rs

@@ -1,7 +1,17 @@
 use crate::{borrowed, SHA1_SIZE};
 use bstr::ByteSlice;
+use quick_error::quick_error;
 use std::{fmt, io, ops::Deref};
 
+quick_error! {
+    #[derive(Debug)]
+    pub enum Error {
+        HexDecode(err: String) {
+            display("Failed to hex hash: {}", err)
+        }
+    }
+}
+
 /// An owned SHA1 identifying objects
 #[derive(PartialEq, Eq, Debug, Hash, Ord, PartialOrd, Clone, Copy)]
 #[cfg_attr(feature = "serde1", derive(serde::Serialize, serde::Deserialize))]
@@ -30,9 +40,11 @@ impl Id {
 
 /// Sha1 hash specific methods
 impl Id {
-    pub fn from_40_bytes_in_hex(buf: &[u8]) -> Result<Id, hex::FromHexError> {
+    pub fn from_40_bytes_in_hex(buf: &[u8]) -> Result<Id, Error> {
         use hex::FromHex;
-        Ok(Id(<[u8; 20]>::from_hex(buf)?))
+        Ok(Id(
+            <[u8; 20]>::from_hex(buf).map_err(|err| Error::HexDecode(err.to_string()))?
+        ))
     }
     pub fn sha1(&self) -> &[u8; SHA1_SIZE] {
         &self.0

git-packetline/src/decode.rs

@@ -7,10 +7,8 @@ use quick_error::quick_error;
 quick_error! {
     #[derive(Debug)]
     pub enum Error {
-        HexDecode(err: hex::FromHexError) {
-            display("Failed to decode the first four hex bytes indicating the line length")
-            from()
-            source(err)
+        HexDecode(err: String) {
+            display("Failed to decode the first four hex bytes indicating the line length: {}", err)
         }
         DataLengthLimitExceeded(length_in_bytes: usize) {
             display("The data received claims to be larger than than the maximum allowed size: got {}, exceeds {}", length_in_bytes, MAX_DATA_LEN)
@@ -60,7 +58,7 @@ pub fn hex_prefix(four_bytes: &[u8]) -> Result<PacketLineOrWantedSize, Error> {
     }
 
     let mut buf = [0u8; U16_HEX_BYTES / 2];
-    hex::decode_to_slice(four_bytes, &mut buf)?;
+    hex::decode_to_slice(four_bytes, &mut buf).map_err(|err| Error::HexDecode(err.to_string()))?;
     let wanted_bytes = u16::from_be_bytes(buf);
     if wanted_bytes == 3 {
         return Err(Error::InvalidLineLength);