fix: don't crash when object validation failed during verification.

When objects can't be serialized, they will trigger an error that manifests as IO error.
Previously we didn't think of the possibility that writing to an im-memory buffer could fail
would indeed panic during verification.

This is now fixed.

Author: Byron

gitoxide-core/src/corpus/mod.rs

@@ -1,4 +1,4 @@
-pub const PROGRESS_RANGE: std::ops::RangeInclusive<u8> = 0..=3;
+pub const PROGRESS_RANGE: std::ops::RangeInclusive<u8> = 0..=5;
 
 pub struct Engine {
     con: rusqlite::Connection,

gix-pack/src/index/verify.rs

@@ -15,6 +15,8 @@ pub mod integrity {
     #[derive(thiserror::Error, Debug)]
     #[allow(missing_docs)]
     pub enum Error {
+        #[error("Reserialization of an object failed")]
+        Io(#[from] std::io::Error),
         #[error("The fan at index {index} is out of order as it's larger then the following value.")]
         Fan { index: usize },
         #[error("{kind} object {id} could not be decoded")]
@@ -252,9 +254,7 @@ impl index::File {
                     })?;
                     if let Mode::HashCrc32DecodeEncode = verify_mode {
                         encode_buf.clear();
-                        object
-                            .write_to(&mut *encode_buf)
-                            .expect("writing to a memory buffer never fails");
+                        object.write_to(&mut *encode_buf)?;
                         if encode_buf.as_slice() != buf {
                             let mut should_return_error = true;
                             if let Tree = object_kind {