validate data CID is present on write

crates/dwn/src/actor/mod.rs

@@ -97,7 +97,7 @@ impl<D: DataStore, M: MessageStore> Actor<D, M> {
             }
         }
 
-        // Pull from remotes.
+        // Pull all local records from remotes.
         let mut record_ids = HashSet::new();
 
         for message in self

crates/dwn/src/handlers/records/write.rs

@@ -45,6 +45,22 @@ pub async fn handle_records_write(
         }
     };
 
+    // Validate data format is present.
+    if message.data.is_some() && descriptor.data_format.is_none() {
+        return Err(HandleMessageError::InvalidDescriptor(
+            "Data format missing".to_string(),
+        ));
+    }
+
+    // Validate data CID is present.
+    // We do not validate the CID, because we may want to store a record
+    // without storing its associated data.
+    if message.data.is_some() && descriptor.data_cid.is_none() {
+        return Err(HandleMessageError::InvalidDescriptor(
+            "Data CID missing".to_string(),
+        ));
+    }
+
     // Get messages for the record.
     let messages = message_store
         .query_records(
@@ -87,13 +103,6 @@ pub async fn handle_records_write(
         }
     }
 
-    // Validate data format is present.
-    if message.data.is_some() && descriptor.data_format.is_none() {
-        return Err(HandleMessageError::InvalidDescriptor(
-            "Data format missing".to_string(),
-        ));
-    }
-
     // Validate data matches schema.
     if let Some(schema_url) = &descriptor.schema {
         if let Some(Data::Base64(data)) = &message.data {