graph: Validate if pruning is decalred for source subgraph

Author: incrypto32

graph/src/data/subgraph/mod.rs

@@ -583,7 +583,7 @@ pub struct BaseSubgraphManifest<C, S, D, T> {
 #[derive(Debug, Deserialize)]
 #[serde(rename_all = "camelCase")]
 pub struct IndexerHints {
-    prune: Option<Prune>,
+    pub prune: Option<Prune>,
 }
 
 impl IndexerHints {

graph/src/data_source/subgraph.rs

@@ -294,6 +294,17 @@ impl UnresolvedDataSource {
             ));
         }
 
+        let pruning_enabled = match source_manifest.indexer_hints.as_ref() {
+            None => false,
+            Some(hints) => hints.prune.is_some(),
+        };
+
+        if pruning_enabled {
+            return Err(anyhow!(
+                "Pruning is enabled for source subgraph, which is not supported"
+            ));
+        }
+
         let mapping_entities: Vec<String> = self
             .mapping
             .handlers