feat: warn user when unused features are defined

src/project/manifest/validation.rs

@@ -36,6 +36,22 @@ impl ProjectManifest {
             }
         }
 
+        // Check if all features are used in environments, warn if not.
+        let mut features_used = HashSet::new();
+        for env in self.environments.values() {
+            for feature in env.features.iter() {
+                features_used.insert(feature);
+            }
+        }
+        for (name, _feature) in self.features.iter() {
+            if name != &FeatureName::Default && !features_used.contains(&name.to_string()) {
+                tracing::warn!(
+                    "The feature '{}' is defined but not used in any environment",
+                    console::style(name).bold().blue()
+                );
+            }
+        }
+
         // parse the SPDX license expression to make sure that it is a valid expression.
         if let Some(spdx_expr) = &self.project.license {
             spdx::Expression::parse(spdx_expr)