Small fixes to eval logging

src/nix/host.rs

@@ -147,12 +147,17 @@ impl Host for Local {
             execution.set_progress_bar(bar.clone());
         }
 
-        execution.run().await?;
+        let result = execution.run().await;
 
         let (stdout, stderr) = execution.get_logs();
         self.logs += stderr.unwrap();
 
-        stdout.unwrap().lines().map(|p| p.to_string().try_into()).collect()
+        match result {
+            Ok(()) => {
+                stdout.unwrap().lines().map(|p| p.to_string().try_into()).collect()
+            }
+            Err(e) => Err(e),
+        }
     }
     async fn activate(&mut self, profile: &Profile, goal: DeploymentGoal) -> NixResult<()> {
         if goal.should_switch_profile() {

src/nix/store.rs

@@ -2,6 +2,7 @@ use std::convert::{TryFrom, TryInto};
 use std::marker::PhantomData;
 use std::path::{Path, PathBuf};
 use std::ops::Deref;
+use std::fmt;
 
 use serde::{Serialize, Deserialize};
 
@@ -84,3 +85,9 @@ impl<T: TryFrom<Vec<StorePath>, Error=NixError>> StoreDerivation<T> {
         paths.try_into()
     }
 }
+
+impl<T: TryFrom<Vec<StorePath>>> fmt::Display for StoreDerivation<T> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "{:?}", self.path)
+    }
+}