Fix distinct queries on fields with array values #70

bwaldvogel · Jun 10, 2019 · 7449324 · 7449324
1 parent 2424ba2
commit 7449324
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diff --git a/core/src/main/java/de/bwaldvogel/mongo/backend/AbstractMongoCollection.java b/core/src/main/java/de/bwaldvogel/mongo/backend/AbstractMongoCollection.java
@@ -345,7 +345,11 @@ public synchronized Document handleDistinct(Document query) {
         for (Document document : queryDocuments(filter, null, 0, 0)) {
             Object value = Utils.getSubdocumentValue(document, key);
             if (!(value instanceof Missing)) {
-                values.add(value);
+                if (value instanceof Collection) {
+                    values.addAll((Collection<?>) value);
+                } else {
+                    values.add(value);
+                }
             }
         }
 

diff --git a/test-common/src/main/java/de/bwaldvogel/mongo/backend/AbstractBackendTest.java b/test-common/src/main/java/de/bwaldvogel/mongo/backend/AbstractBackendTest.java
@@ -478,6 +478,18 @@ public void testDistinctUuids() throws Exception {
             );
     }
 
+    // https://github.com/bwaldvogel/mongo-java-server/issues/70
+    @Test
+    public void testDistinctArrayField() throws Exception {
+        collection.insertOne(json("_id: 1, n: null"));
+        collection.insertOne(json("_id: 2").append("n", Arrays.asList(1, 2, 3)));
+        collection.insertOne(json("_id: 3").append("n", Arrays.asList(3, 4, 5)));
+        collection.insertOne(json("_id: 4").append("n", 6));
+
+        assertThat(toArray(collection.distinct("n", Integer.class)))
+            .containsExactly(null, 1, 2, 3, 4, 5, 6);
+    }
+
     @Test
     public void testInsertQueryAndSortBinaryTypes() throws Exception {
         byte[] highBytes = new byte[16];