fix: return error instead of panicking if fetching from ipfs fails

Author: pcarranzav

crates/dips/src/ipfs.rs

@@ -50,7 +50,7 @@ impl IpfsFetcher for IpfsClient {
             .map_ok(|chunk| chunk.to_vec())
             .try_concat()
             .await
-            .unwrap();
+            .map_err(|_| DipsError::SubgraphManifestUnavailable(file.to_string()))?;
 
         let manifest: GraphManifest = serde_yaml::from_slice(&content)
             .map_err(|_| DipsError::InvalidSubgraphManifest(file.to_string()))?;

crates/dips/src/lib.rs

@@ -139,6 +139,8 @@ pub enum DipsError {
     PayerNotAuthorised(Address),
     #[error("voucher payee {actual} does not match the expected address {expected}")]
     UnexpectedPayee { expected: Address, actual: Address },
+    #[error("cannot get subgraph manifest for {0}")]
+    SubgraphManifestUnavailable(String),
     #[error("invalid subgraph id {0}")]
     InvalidSubgraphManifest(String),
     #[error("voucher for chain id {0}, subgraph manifest has network {1}")]