add validation & tests for unused features in subgraph manifest

graph/src/data/subgraph/features.rs

@@ -64,6 +64,10 @@ pub enum SubgraphFeatureValidationError {
     #[error("The feature `{}` is used by the subgraph but it is not declared in the manifest.", fmt_subgraph_features(.0))]
     Undeclared(BTreeSet<SubgraphFeature>),
 
+    /// A feature is declared in the `features` section of the manifest file but it is not used by the subgraph.
+    #[error("The feature `{}` is not used by the subgraph but it is declared in the manifest.", fmt_subgraph_features(.0))]
+    Unused(BTreeSet<SubgraphFeature>),
+
     /// The provided compiled mapping is not a valid WASM module.
     #[error("Failed to parse the provided mapping WASM module")]
     InvalidMapping,
@@ -79,7 +83,10 @@ pub fn validate_subgraph_features<C: Blockchain>(
     let declared: &BTreeSet<SubgraphFeature> = &manifest.features;
     let used = detect_features(manifest)?;
     let undeclared: BTreeSet<SubgraphFeature> = used.difference(declared).cloned().collect();
-    if !undeclared.is_empty() {
+    let unsed: BTreeSet<SubgraphFeature> = declared.difference(&used).cloned().collect();
+    if !unsed.is_empty() {
+        Err(SubgraphFeatureValidationError::Unused(unsed))
+    } else if !undeclared.is_empty() {
         Err(SubgraphFeatureValidationError::Undeclared(undeclared))
     } else {
         Ok(used)

store/test-store/tests/chain/ethereum/manifest.rs

@@ -1210,6 +1210,42 @@ graft:
     })
 }
 
+#[test]
+fn can_detect_unsed_feature_in_subgraph_manifest() {
+    const YAML: &str = "
+specVersion: 0.0.4
+dataSources: []
+features:
+  - grafting
+  - fullTextSearch
+  - ipfsOnEthereumContracts
+schema:
+  file:
+    /: /ipfs/Qmschema
+";
+    test_store::run_test_sequentially(|store| async move {
+        let store = store.subgraph_store();
+        let unvalidated = resolve_unvalidated(YAML).await;
+        let error_msg = unvalidated
+            .validate(store.clone(), true)
+            .await
+            .expect_err("Validation must fail")
+            .into_iter()
+            .find(|e| {
+                matches!(
+                    e,
+                    SubgraphManifestValidationError::FeatureValidationError(_)
+                )
+            })
+            .expect("There must be a FeatureValidation error")
+            .to_string();
+        assert_eq!(
+            "The feature `grafting, fullTextSearch, ipfsOnEthereumContracts` is not used by the subgraph but it is declared in the manifest.",
+            error_msg
+        )
+    })
+}
+
 #[test]
 fn declared_grafting_feature_causes_no_feature_validation_errors() {
     const YAML: &str = "