Use error macro in a few places

Author: Artturin

src/cache.rs

@@ -1,7 +1,7 @@
 use std::{collections::HashMap, error::Error, fs, path::PathBuf};
 
 use bitcode::{Decode, Encode};
-use log::debug;
+use log::{debug, error};
 
 #[derive(Encode, Decode)]
 struct CacheData(HashMap<String, CacheEntry>);
@@ -66,7 +66,7 @@ impl Drop for Cache {
             debug!("writing cache to disk: {}", self.path.display());
             let bytes = bitcode::encode(&self.data.0);
             if let Err(e) = fs::write(&self.path, bytes) {
-                eprintln!("failed to write cache: {e}");
+                error!("failed to write cache: {e}");
             }
         }
     }

src/main.rs

@@ -13,7 +13,7 @@ use std::{
 use cache::{Cache, CacheEntry};
 use clap::crate_version;
 use clap::Parser;
-use log::{debug, trace};
+use log::{debug, error, trace};
 
 fn pick(picker: &str, derivations: &[String]) -> Option<String> {
     let mut picker_process = Command::new(picker)
@@ -240,7 +240,7 @@ fn main() -> ExitCode {
     } else {
         match Cache::new() {
             Err(e) => {
-                eprintln!("failed to initialize cache, disabling related functionality: {e}");
+                error!("failed to initialize cache, disabling related functionality: {e}");
                 None
             }
             Ok(x) => Some(x),