maybe_override_nixpkgs_config -> override_nixpkgs_config

Author: dschrempf

nix-script-directives/src/lib.rs

@@ -163,16 +163,14 @@ impl Directives {
         }
     }
 
-    pub fn maybe_override_nixpkgs_config(&mut self, new: Option<&Expr>) -> Result<()> {
-        if let Some(expr) = new {
-            match expr.kind() {
-                SyntaxKind::NODE_ATTR_SET => self.nixpkgs_config = Some(expr.clone()),
-                other => anyhow::bail!(
-                    "I expected the nixpkgs config to be a Nix record, but it was a `{:?}`",
-                    other,
-                ),
-            };
-        }
+    pub fn override_nixpkgs_config(&mut self, expr: &Expr) -> Result<()> {
+        match expr.kind() {
+            SyntaxKind::NODE_ATTR_SET => self.nixpkgs_config = Some(expr.clone()),
+            other => anyhow::bail!(
+                "Nixpkgs config was no Nix attribute set, but a `{:?}`",
+                other,
+            ),
+        };
 
         Ok(())
     }

nix-script/src/main.rs

@@ -184,9 +184,11 @@ impl Opts {
             .merge_runtime_inputs(&self.runtime_inputs)
             .context("could not add runtime inputs provided on the command line")?;
         directives.merge_runtime_files(&self.runtime_files);
-        directives
-            .maybe_override_nixpkgs_config(self.nixpkgs_config.as_ref())
-            .context("could not set nixpkgs config provided on the command line")?;
+        if let Some(expr) = self.nixpkgs_config.as_ref() {
+            directives
+                .override_nixpkgs_config(expr)
+                .context("could not set nixpkgs config provided on the command line")?;
+        }
 
         // Second place we might bail early: if we're requesting a shell instead
         // of building and running the script.