feat(tvix/derivation): more checks for output hashes and encoding

Change-Id: Idebad60c3bf9daf94d04a36bb73ac0dd767f9e79
Reviewed-on: https://cl.tvl.fyi/c/depot/+/7856
Reviewed-by: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI

tvix/derivation/src/errors.rs

@@ -47,4 +47,10 @@ pub enum DerivationError {
 pub enum OutputError {
     #[error("Invalid ouput path {0}: {1}")]
     InvalidOutputPath(String, ParseStorePathError),
+    #[error("Invalid hash encoding: {0}")]
+    InvalidHashEncoding(String, data_encoding::DecodeError),
+    #[error("Invalid hash algo: {0}")]
+    InvalidHashAlgo(String),
+    #[error("Invalid Digest size {0} for algo {1}")]
+    InvalidDigestSizeForAlgo(usize, String),
 }