Fix inconsistent handling of piped edges (#294)

lib/src/memory/datastore.rs

@@ -157,10 +157,11 @@ impl<'a> Transaction<'a> for MemoryTransaction<'a> {
                 }));
                 Ok(Some(Box::new(iter.map(|e| Ok(e.clone())))))
             } else {
-                Ok(None)
+                let iter = Vec::default().into_iter();
+                Ok(Some(Box::new(iter)))
             }
         } else {
-            Err(Error::NotIndexed)
+            Ok(None)
         }
     }
 

lib/src/tests/edge.rs

@@ -2,8 +2,8 @@ use std::collections::HashSet;
 
 use super::util;
 use crate::{
-    ijson, models, AllEdgeQuery, Database, Datastore, Edge, EdgeDirection, Error, QueryExt, SpecificEdgeQuery,
-    SpecificVertexQuery,
+    ijson, models, AllEdgeQuery, Database, Datastore, Edge, EdgeDirection, EdgeWithPropertyValueQuery, Error,
+    Identifier, QueryExt, SpecificEdgeQuery, SpecificVertexQuery,
 };
 
 use uuid::Uuid;
@@ -221,6 +221,14 @@ pub fn should_get_edges_piped<D: Datastore>(db: &Database<D>) -> Result<(), Erro
     Ok(())
 }
 
+/// Test for a regression, see
+/// https://github.com/indradb/indradb/issues/278#issuecomment-1515797381
+pub fn should_delete_indexed_edge_with_property_value<D: Datastore>(db: &Database<D>) -> Result<(), Error> {
+    db.index_property(Identifier::new("k")?)?;
+    db.delete(EdgeWithPropertyValueQuery::new(Identifier::new("k")?, ijson!(null)))?;
+    Ok(())
+}
+
 fn check_edge_range(range: &[models::Edge], expected_outbound_id: Uuid, expected_length: usize) -> Result<(), Error> {
     assert_eq!(range.len(), expected_length);
     let mut covered_ids: HashSet<Uuid> = HashSet::new();

lib/src/tests/macros.rs

@@ -67,6 +67,7 @@ macro_rules! full_test_impl {
         define_test!(should_get_edge_range, $code);
         define_test!(should_get_edges, $code);
         define_test!(should_get_edges_piped, $code);
+        define_test!(should_delete_indexed_edge_with_property_value, $code);
 
         // Include queries
         define_test!(should_get_nested_include_query, $code);