Merge pull request #1649 from cachix/direnv-feats

devenv: caching fixes and improvements
cachix · Dec 23, 2024 · 4b8677f · 4b8677f
2 parents 9e1b29e + cfe2a0b
commit 4b8677f
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Showing 2 changed files with 22 additions and 14 deletions.
diff --git a/devenv/src/cnix.rs b/devenv/src/cnix.rs
@@ -355,7 +355,6 @@ impl<'a> Nix<'a> {
             cached_cmd.watch_path(self.devenv_root.join("devenv.yaml"));
             cached_cmd.watch_path(self.devenv_root.join("devenv.lock"));
 
-            cached_cmd.unwatch_path(self.devenv_root.join(".devenv.flake.nix"));
             // Ignore anything in .devenv.
             cached_cmd.unwatch_path(&self.devenv_dotfile);
 
@@ -448,8 +447,8 @@ impl<'a> Nix<'a> {
         options: &Options<'a>,
     ) -> Result<std::process::Command> {
         let mut final_args = Vec::new();
-        let known_keys;
-        let pull_caches;
+        let known_keys_str;
+        let pull_caches_str;
         let mut push_cache = None;
 
         if !self.global_options.offline {
@@ -464,28 +463,31 @@ impl<'a> Nix<'a> {
                     push_cache = cachix_caches.caches.push.clone();
                     // handle cachix.pull
                     if !cachix_caches.caches.pull.is_empty() {
-                        pull_caches = cachix_caches
+                        let mut pull_caches = cachix_caches
                             .caches
                             .pull
                             .iter()
                             .map(|cache| format!("https://{}.cachix.org", cache))
-                            .collect::<Vec<String>>()
-                            .join(" ");
+                            .collect::<Vec<String>>();
+                        pull_caches.sort();
+                        pull_caches_str = pull_caches.join(" ");
                         final_args.extend_from_slice(&[
                             "--option",
                             "extra-substituters",
-                            &pull_caches,
+                            &pull_caches_str,
                         ]);
-                        known_keys = cachix_caches
+
+                        let mut known_keys = cachix_caches
                             .known_keys
                             .values()
                             .cloned()
-                            .collect::<Vec<String>>()
-                            .join(" ");
+                            .collect::<Vec<String>>();
+                        known_keys.sort();
+                        known_keys_str = known_keys.join(" ");
                         final_args.extend_from_slice(&[
                             "--option",
                             "extra-trusted-public-keys",
-                            &known_keys,
+                            &known_keys_str,
                         ]);
                     }
                 }

diff --git a/devenv/src/devenv.rs b/devenv/src/devenv.rs
@@ -773,7 +773,7 @@ impl Devenv {
                 $ devenv init
             "});
         }
-        std::fs::create_dir_all(&self.devenv_dot_gc)
+        fs::create_dir_all(&self.devenv_dot_gc)
             .unwrap_or_else(|_| panic!("Failed to create {}", self.devenv_dot_gc.display()));
 
         let mut flake_inputs = HashMap::new();
@@ -832,8 +832,14 @@ impl Devenv {
             is_testing
         );
         let flake = FLAKE_TMPL.replace("__DEVENV_VARS__", &vars);
-        std::fs::write(self.devenv_root.join(DEVENV_FLAKE), flake)
-            .expect("Failed to write flake.nix");
+        let flake_path = self.devenv_root.join(DEVENV_FLAKE);
+
+        // Avoid writing the flake if it hasn't changed.
+        // direnv's watch_file triggers a reload based solely on mtime, which becomes annoying if we constantly touch this file.
+        let existing_flake = fs::read_to_string(&flake_path).unwrap_or_default();
+        if flake != existing_flake {
+            fs::write(flake_path, flake).expect("Failed to write flake.nix");
+        }
 
         self.assembled = true;
         Ok(())