From 1d01fc7f81032e01c08cb7ba03ac0f65245c7922 Mon Sep 17 00:00:00 2001
From: Dominik Spicher <dominikspicher@gmail.com>
Date: Thu, 6 Feb 2025 21:56:54 +0100
Subject: [PATCH 1/2] fountain/doctest: simplify xor function

---
 src/fountain.rs | 8 ++------
 1 file changed, 2 insertions(+), 6 deletions(-)

diff --git a/src/fountain.rs b/src/fountain.rs
index 85d7453..c9ddc0d 100644
--- a/src/fountain.rs
+++ b/src/fountain.rs
@@ -8,12 +8,8 @@
 //! A seeded `Xoshiro` RNG ensures that the receiver can reconstruct which segments
 //! were combined into the part.
 //! ```
-//! let xor = |a: &[u8], b: &[u8]| {
-//!     a.iter()
-//!         .zip(b.iter())
-//!         .map(|(&x1, &x2)| x1 ^ x2)
-//!         .collect::<Vec<_>>()
-//! };
+//! let xor =
+//!     |a: &[u8], b: &[u8]| -> Vec<_> { a.iter().zip(b.iter()).map(|(x1, x2)| x1 ^ x2).collect() };
 //!
 //! let data = String::from("Ten chars!");
 //! let max_length = 4;

From dda3c7f20be2b316c10096bf995663d195d26bcc Mon Sep 17 00:00:00 2001
From: Dominik Spicher <dominikspicher@gmail.com>
Date: Thu, 6 Feb 2025 22:06:15 +0100
Subject: [PATCH 2/2] fountain/ur: tweak error messages

 - Prepend with context if applicable.

 - Consistently start lower-cased.

 - Test more formattings.
---
 src/fountain.rs | 12 ++++++++++--
 src/ur.rs       | 32 ++++++++++++++++++++------------
 2 files changed, 30 insertions(+), 14 deletions(-)

diff --git a/src/fountain.rs b/src/fountain.rs
index c9ddc0d..1506419 100644
--- a/src/fountain.rs
+++ b/src/fountain.rs
@@ -102,8 +102,8 @@ pub enum Error {
 impl core::fmt::Display for Error {
     fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
         match self {
-            Self::CborDecode(e) => write!(f, "{e}"),
-            Self::CborEncode(e) => write!(f, "{e}"),
+            Self::CborDecode(e) => write!(f, "minicbor decoding error: {e}"),
+            Self::CborEncode(e) => write!(f, "minicbor encoding error: {e}"),
             Self::EmptyMessage => write!(f, "expected non-empty message"),
             Self::EmptyPart => write!(f, "expected non-empty part"),
             Self::InvalidFragmentLen => write!(f, "expected positive maximum fragment length"),
@@ -1102,6 +1102,14 @@ mod tests {
 
     #[test]
     fn test_error_formatting() {
+        assert_eq!(
+            super::Error::from(minicbor::decode::Error::end_of_input()).to_string(),
+            "minicbor decoding error: end of input bytes"
+        );
+        assert_eq!(
+            super::Error::from(minicbor::encode::Error::message("error")).to_string(),
+            "minicbor encoding error: error"
+        );
         assert_eq!(
             super::Error::EmptyMessage.to_string(),
             "expected non-empty message"
diff --git a/src/ur.rs b/src/ur.rs
index 929a22a..cccd976 100644
--- a/src/ur.rs
+++ b/src/ur.rs
@@ -50,13 +50,13 @@ pub enum Error {
 impl core::fmt::Display for Error {
     fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
         match self {
-            Self::Bytewords(e) => write!(f, "{e}"),
-            Self::Fountain(e) => write!(f, "{e}"),
-            Self::InvalidScheme => write!(f, "Invalid scheme"),
-            Self::TypeUnspecified => write!(f, "No type specified"),
-            Self::InvalidCharacters => write!(f, "Type contains invalid characters"),
-            Self::InvalidIndices => write!(f, "Invalid indices"),
-            Self::NotMultiPart => write!(f, "Can't decode single-part UR as multi-part"),
+            Self::Bytewords(e) => write!(f, "bytewords: {e}"),
+            Self::Fountain(e) => write!(f, "fountain: {e}"),
+            Self::InvalidScheme => write!(f, "invalid scheme"),
+            Self::TypeUnspecified => write!(f, "no type specified"),
+            Self::InvalidCharacters => write!(f, "type contains invalid characters"),
+            Self::InvalidIndices => write!(f, "invalid indices"),
+            Self::NotMultiPart => write!(f, "can't decode single-part UR as multi-part"),
         }
     }
 }
@@ -468,19 +468,27 @@ mod tests {
 
     #[test]
     fn test_error_formatting() {
-        assert_eq!(super::Error::InvalidScheme.to_string(), "Invalid scheme");
+        assert_eq!(
+            super::Error::from(crate::bytewords::Error::InvalidChecksum).to_string(),
+            "bytewords: invalid checksum"
+        );
+        assert_eq!(
+            super::Error::from(crate::fountain::Error::EmptyPart).to_string(),
+            "fountain: expected non-empty part"
+        );
+        assert_eq!(super::Error::InvalidScheme.to_string(), "invalid scheme");
         assert_eq!(
             super::Error::TypeUnspecified.to_string(),
-            "No type specified"
+            "no type specified"
         );
         assert_eq!(
             super::Error::InvalidCharacters.to_string(),
-            "Type contains invalid characters"
+            "type contains invalid characters"
         );
-        assert_eq!(super::Error::InvalidIndices.to_string(), "Invalid indices");
+        assert_eq!(super::Error::InvalidIndices.to_string(), "invalid indices");
         assert_eq!(
             super::Error::NotMultiPart.to_string(),
-            "Can't decode single-part UR as multi-part"
+            "can't decode single-part UR as multi-part"
         );
     }
 }