1 files changed, 99 insertions, 0 deletions
diff --git a/jstests/core/query/distinct/distinct_array1.js b/jstests/core/query/distinct/distinct_array1.js
new file mode 100644
index 00000000000..cb82c25bbff
--- /dev/null
+++ b/jstests/core/query/distinct/distinct_array1.js
@@ -0,0 +1,99 @@
+t = db.distinct_array1;
+t.drop();
+
+t.save({a: [1, 2, 3]});
+t.save({a: [2, 3, 4]});
+t.save({a: [3, 4, 5]});
+t.save({a: 9});
+
+// Without index.
+res = t.distinct("a").sort();
+assert.eq("1,2,3,4,5,9", res.toString());
+
+// Array element 0 without index.
+res = t.distinct("a.0").sort();
+assert.eq("1,2,3", res.toString());
+
+// Array element 1 without index.
+res = t.distinct("a.1").sort();
+assert.eq("2,3,4", res.toString());
+
+// With index.
+t.createIndex({a: 1});
+res = t.distinct("a").sort();
+assert.eq("1,2,3,4,5,9", res.toString());
+
+// Array element 0 with index.
+res = t.distinct("a.0").sort();
+assert.eq("1,2,3", res.toString());
+
+// Array element 1 with index.
+res = t.distinct("a.1").sort();
+assert.eq("2,3,4", res.toString());
+
+t.save({a: [{b: "a"}, {b: "d"}], c: 12});
+t.save({a: [{b: "b"}, {b: "d"}], c: 12});
+t.save({a: [{b: "c"}, {b: "e"}], c: 12});
+t.save({a: [{b: "c"}, {b: "f"}], c: 12});
+t.save({a: [], c: 12});
+t.save({a: {b: "z"}, c: 12});
+
+// Without index.
+res = t.distinct("a.b").sort();
+assert.eq("a,b,c,d,e,f,z", res.toString());
+
+// Array element 0 without index
+res = t.distinct("a.0.b").sort();
+assert.eq("a,b,c", res.toString());
+
+// Array element 1 without index
+res = t.distinct("a.1.b").sort();
+assert.eq("d,e,f", res.toString());
+
+// With index.
+t.createIndex({"a.b": 1});
+res = t.distinct("a.b");
+res.sort();
+// TODO SERVER-14832 The presence of an index may change results, but only if the index is not
+// multikey.
+// In a sharded scenario, an unlucky distribution of data will cause all the arrays to go to one
+// shard, and one shard be left with only non-multikey documents, including one with {a: 9}, which
+// will generate a null result.
+if (res.includes(null)) {
+    // The default sorting of an array is by string, so null will appear in an odd position.
+    assert.eq(res, ["a", "b", "c", "d", "e", "f", null, "z"]);
+} else {
+    assert.eq("a,b,c,d,e,f,z", res.toString());
+}
+
+// _id as an document containing an array
+t.save({_id: {a: [1, 2, 3]}});
+t.save({_id: {a: [2, 3, 4]}});
+t.save({_id: {a: [3, 4, 5]}});
+t.save({_id: {a: 9}});
+
+// Without index.
+res = t.distinct("_id.a").sort();
+assert.eq("1,2,3,4,5,9", res.toString());
+
+// Array element 0 without index.
+res = t.distinct("_id.a.0").sort();
+assert.eq("1,2,3", res.toString());
+
+// Array element 1 without index.
+res = t.distinct("_id.a.1").sort();
+assert.eq("2,3,4", res.toString());
+
+// With index.
+t.createIndex({"_id.a": 1});
+res = t.distinct("_id.a").sort();
+// TODO SERVER-14832: distinct() may incorrectly return null in presence of index.
+assert.eq([1, 2, 3, 4, 5, 9, null], res);
+
+// Array element 0 with index.
+res = t.distinct("_id.a.0").sort();
+assert.eq("1,2,3", res.toString());
+
+// Array element 1 with index.
+res = t.distinct("_id.a.1").sort();
+assert.eq("2,3,4", res.toString());