feat(nix-compat): Use serde_with for HashAlgo serialization

We already have serde_with in the workspace and using it cuts down
on code lines (very slightly).

This also adds a FromStr implementation for HashAlgo in addition to
the existing TryFrom<&str>.

Change-Id: I1b525d7391f3881d54cef0c74d22198ad394f47d
Reviewed-on: https://cl.snix.dev/c/snix/+/30652
Reviewed-by: Florian Klink <flokli@flokli.de>
Tested-by: besadii
Autosubmit: Brian Olsen <brian@maven-group.org>

contrib/crunch-v2/Cargo.nix

@@ -4178,7 +4178,7 @@ rec {
           "futures" = [ "dep:futures" ];
           "nix-compat-derive" = [ "dep:nix-compat-derive" ];
           "pin-project-lite" = [ "dep:pin-project-lite" ];
-          "serde" = [ "dep:serde" "dep:serde_json" ];
+          "serde" = [ "dep:serde" "dep:serde_json" "dep:serde_with" ];
           "tokio" = [ "dep:tokio" ];
           "url" = [ "dep:url" ];
           "wire" = [ "tokio" "pin-project-lite" "bytes" ];

contrib/fetchroots/Cargo.nix

@@ -5611,7 +5611,7 @@ rec {
           "futures" = [ "dep:futures" ];
           "nix-compat-derive" = [ "dep:nix-compat-derive" ];
           "pin-project-lite" = [ "dep:pin-project-lite" ];
-          "serde" = [ "dep:serde" "dep:serde_json" ];
+          "serde" = [ "dep:serde" "dep:serde_json" "dep:serde_with" ];
           "tokio" = [ "dep:tokio" ];
           "url" = [ "dep:url" ];
           "wire" = [ "tokio" "pin-project-lite" "bytes" ];

contrib/narinfo2parquet/Cargo.nix

@@ -2905,7 +2905,7 @@ rec {
           "futures" = [ "dep:futures" ];
           "nix-compat-derive" = [ "dep:nix-compat-derive" ];
           "pin-project-lite" = [ "dep:pin-project-lite" ];
-          "serde" = [ "dep:serde" "dep:serde_json" ];
+          "serde" = [ "dep:serde" "dep:serde_json" "dep:serde_with" ];
           "tokio" = [ "dep:tokio" ];
           "url" = [ "dep:url" ];
           "wire" = [ "tokio" "pin-project-lite" "bytes" ];

contrib/weave/Cargo.nix

@@ -2987,7 +2987,7 @@ rec {
           "futures" = [ "dep:futures" ];
           "nix-compat-derive" = [ "dep:nix-compat-derive" ];
           "pin-project-lite" = [ "dep:pin-project-lite" ];
-          "serde" = [ "dep:serde" "dep:serde_json" ];
+          "serde" = [ "dep:serde" "dep:serde_json" "dep:serde_with" ];
           "tokio" = [ "dep:tokio" ];
           "url" = [ "dep:url" ];
           "wire" = [ "tokio" "pin-project-lite" "bytes" ];

snix/Cargo.lock

@@ -2613,6 +2613,7 @@ dependencies = [
  "rstest",
  "serde",
  "serde_json",
+ "serde_with",
  "sha2",
  "smol_str",
  "thiserror 2.0.9",

snix/Cargo.nix

@@ -8300,6 +8300,13 @@ rec {
             packageId = "serde_json";
             optional = true;
           }
+          {
+            name = "serde_with";
+            packageId = "serde_with";
+            optional = true;
+            usesDefaultFeatures = false;
+            features = [ "macros" ];
+          }
           {
             name = "sha2";
             packageId = "sha2";
@@ -8383,7 +8390,7 @@ rec {
           "futures" = [ "dep:futures" ];
           "nix-compat-derive" = [ "dep:nix-compat-derive" ];
           "pin-project-lite" = [ "dep:pin-project-lite" ];
-          "serde" = [ "dep:serde" "dep:serde_json" ];
+          "serde" = [ "dep:serde" "dep:serde_json" "dep:serde_with" ];
           "tokio" = [ "dep:tokio" ];
           "url" = [ "dep:url" ];
           "wire" = [ "tokio" "pin-project-lite" "bytes" ];
@@ -13770,6 +13777,8 @@ rec {
           {
             name = "serde_with";
             packageId = "serde_with";
+            usesDefaultFeatures = false;
+            features = [ "macros" ];
           }
           {
             name = "snix-tracing";
@@ -14685,6 +14694,8 @@ rec {
           {
             name = "serde_with";
             packageId = "serde_with";
+            usesDefaultFeatures = false;
+            features = [ "macros" ];
           }
           {
             name = "sha1";

snix/Cargo.toml

@@ -117,7 +117,9 @@ serde = "1.0.209"
 serde_json = "1.0"
 serde_qs = "0.12.0"
 serde_tagged = "0.3.0"
-serde_with = "3.9.0"
+serde_with = { version = "3.9.0", default-features = false, features = [
+  "macros",
+] }
 sha1 = "0.10.6"
 sha2 = "0.10.8"
 smol_str = "0.2.2"

snix/nix-compat-derive-tests/tests/ui/deserialize_from_str_missing.stderr

@@ -7,10 +7,10 @@ error[E0277]: the trait bound `Test: FromStr` is not satisfied
   = help: the following other types implement trait `FromStr`:
             ByteString
             CString
+            HashAlgo
             IpAddr
             Ipv4Addr
             Ipv6Addr
             NonZero<i128>
             NonZero<i16>
-            NonZero<i32>
           and $N others

snix/nix-compat/Cargo.toml

@@ -16,7 +16,7 @@ flakeref = ["url"]
 # nix-daemon protocol handling
 daemon = ["tokio", "nix-compat-derive", "futures"]
 # serde support on types
-serde = ["dep:serde", "dep:serde_json"]
+serde = ["dep:serde", "dep:serde_json", "dep:serde_with"]
 test = []
 
 # Enable all features by default.
@@ -36,6 +36,7 @@ nom.workspace = true
 num-traits.workspace = true
 serde = { workspace = true, features = ["derive"], optional = true }
 serde_json = { workspace = true, optional = true }
+serde_with = { workspace = true, optional = true }
 sha2.workspace = true
 thiserror.workspace = true
 tracing.workspace = true

snix/nix-compat/src/nixhash/algos.rs

@@ -1,12 +1,14 @@
 use std::fmt::Display;
+use std::str::FromStr;
 
 #[cfg(feature = "serde")]
-use serde::{Deserialize, Serialize};
+use serde_with::{DeserializeFromStr, SerializeDisplay};
 
 use crate::nixhash::Error;
 
 /// This are the hash algorithms supported by cppnix.
 #[derive(Clone, Copy, Debug, Eq, PartialEq)]
+#[cfg_attr(feature = "serde", derive(DeserializeFromStr, SerializeDisplay))]
 pub enum HashAlgo {
     Md5,
     Sha1,
@@ -37,37 +39,16 @@ impl Display for HashAlgo {
     }
 }
 
-#[cfg(feature = "serde")]
-impl Serialize for HashAlgo {
-    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
-    where
-        S: serde::Serializer,
-    {
-        serializer.collect_str(&self)
-    }
-}
-
-#[cfg(feature = "serde")]
-impl<'de> Deserialize<'de> for HashAlgo {
-    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
-    where
-        D: serde::Deserializer<'de>,
-    {
-        let s: &str = Deserialize::deserialize(deserializer)?;
-        HashAlgo::try_from(s).map_err(serde::de::Error::custom)
-    }
-}
-
 /// TODO(Raito): this could be automated via macros, I suppose.
 /// But this may be more expensive than just doing it by hand
 /// and ensuring that is kept in sync.
 #[cfg(feature = "serde")]
 pub const SUPPORTED_ALGOS: [&str; 4] = ["md5", "sha1", "sha256", "sha512"];
 
-impl TryFrom<&str> for HashAlgo {
-    type Error = Error;
+impl FromStr for HashAlgo {
+    type Err = Error;
 
-    fn try_from(algo_str: &str) -> Result<Self, Self::Error> {
+    fn from_str(algo_str: &str) -> Result<Self, Self::Err> {
         match algo_str {
             "md5" => Ok(Self::Md5),
             "sha1" => Ok(Self::Sha1),
@@ -77,3 +58,10 @@ impl TryFrom<&str> for HashAlgo {
         }
     }
 }
+
+impl TryFrom<&str> for HashAlgo {
+    type Error = Error;
+    fn try_from(algo_str: &str) -> Result<Self, Self::Error> {
+        algo_str.parse()
+    }
+}