refactor(tvix/nix-compat): rename NixHashWithMode -> CAHash r/6871

This specific struct is only used to represent content-addressed paths
(in case a Derivation has a fixed-output hash, for example).
Rename `Output`'s `hash_with_mode` to `ca_hash`.

We now also include `CAHash::Text`, and update the `validate` function
of the `Output` struct to reject text hashes there.

This allows cleaning up the various output path calculation functions
inside nix-compat/src/store_path/utils.rs, as they can now match on
the type.

`make_type` is renamed to `make_references_string`,
`build_regular_ca_path` is renamed to `build_ca_path`, and
`build_text_path` has a disclaimer added, because you might not actually
want to use it.

Change-Id: I674d065f2ed5c804012ddfed56e161ac49d23931
Reviewed-on: https://cl.tvl.fyi/c/depot/+/9814
Tested-by: BuildkiteCI
Reviewed-by: raitobezarius <tvl@lahfa.xyz>

1 files changed, 5 insertions, 7 deletions

diff --git a/tvix/nix-compat/src/derivation/errors.rs b/tvix/nix-compat/src/derivation/errors.rs
index 8e9e6a1210..305957b10f 100644
--- a/tvix/nix-compat/src/derivation/errors.rs
+++ b/tvix/nix-compat/src/derivation/errors.rs
@@ -1,6 +1,8 @@
-use crate::{nixbase32::Nixbase32DecodeError, store_path};
+use crate::store_path;
 use thiserror::Error;
 
+use super::CAHash;
+
 /// Errors that can occur during the validation of Derivation structs.
 #[derive(Debug, Error, PartialEq)]
 pub enum DerivationError {
@@ -50,10 +52,6 @@ pub enum DerivationError {
 pub enum OutputError {
     #[error("Invalid output path {0}: {1}")]
     InvalidOutputPath(String, store_path::Error),
-    #[error("Invalid hash encoding: {0}")]
-    InvalidHashEncoding(String, Nixbase32DecodeError),
-    #[error("Invalid hash algo: {0}")]
-    InvalidHashAlgo(String),
-    #[error("Invalid Digest size {0} for algo {1}")]
-    InvalidDigestSizeForAlgo(usize, String),
+    #[error("Invalid CAHash: {:?}", .0)]
+    InvalidCAHash(CAHash),
 }