1 files changed, 58 insertions, 0 deletions
diff --git a/jstests/core/index/wildcard/wildcard_index_return_key.js b/jstests/core/index/wildcard/wildcard_index_return_key.js
new file mode 100644
index 00000000000..53f7da8c09c
--- /dev/null
+++ b/jstests/core/index/wildcard/wildcard_index_return_key.js
@@ -0,0 +1,58 @@
+/**
+ * Tests that $** indexes works with returnKey option.
+ */
+(function() {
+'use strict';
+
+load("jstests/aggregation/extras/utils.js");
+
+const coll = db.wildcard_return_key;
+coll.drop();
+
+const assertArrayEq = (l, r) => assert(arrayEq(l, r), tojson(l) + " != " + tojson(r));
+const assertArrayNotEq = (l, r) => assert(!arrayEq(l, r), tojson(l) + " == " + tojson(r));
+
+assert.commandWorked(coll.createIndex({"$**": 1}));
+
+assert.commandWorked(coll.insert({a: 1, b: 2, c: {d: 2, e: 1}}));
+assert.commandWorked(coll.insert({a: 2, b: 2, c: {d: 1, e: 2}}));
+assert.commandWorked(coll.insert({a: 2, b: 1, c: {d: 2, e: 2}}));
+assert.commandWorked(coll.insert({a: 1, b: 1, c: {e: 2}}));
+
+// $** index return key with one field argument.
+assertArrayEq(coll.find({a: 1}).returnKey().toArray(),
+              [{"$_path": "a", a: 1}, {"$_path": "a", a: 1}]);
+
+// $** index return key with dot path argument.
+assertArrayEq(coll.find({"c.e": 1}).returnKey().toArray(), [{"$_path": "c.e", "c.e": 1}]);
+
+assert.commandWorked(coll.createIndex({"a": 1}));
+
+// $** index return key with competing regular index.
+assertArrayEq(coll.find({a: 1}).hint({"$**": 1}).returnKey().toArray(),
+              [{"$_path": "a", a: 1}, {"$_path": "a", a: 1}]);
+
+assert.commandWorked(coll.createIndex({"a": 1, "b": 1}));
+
+// $** index return key with competing compound index.
+assertArrayNotEq(coll.find({a: 1, b: 1}).hint({"$**": 1}).returnKey().toArray(), [{a: 1, b: 1}]);
+
+assert.commandWorked(coll.insert({a: 2, b: 2, c: {e: 2}, f: [1, 2, 3]}));
+assert.commandWorked(coll.insert({a: 2, b: 2, c: {e: 2}, g: [{h: 1}, {i: 2}]}));
+
+// Multikey path $** index return key.
+assertArrayEq(coll.find({f: 1}).returnKey().toArray(), [{"$_path": "f", f: 1}]);
+
+// Multikey subobject $** index return key.
+assertArrayEq(coll.find({"g.h": 1}).returnKey().toArray(), [{"$_path": "g.h", "g.h": 1}]);
+
+assert.commandWorked(coll.dropIndexes());
+assert.commandWorked(coll.createIndex({"c.$**": 1}));
+
+// Path specified $** index return key.
+assertArrayEq(coll.find({"c.d": 1}).returnKey().toArray(), [{"$_path": "c.d", "c.d": 1}]);
+
+// Path specified $** index return key with irrelevant query. We expect this query to be
+// answered with a COLLSCAN, in which case returnKey is expected to return empty objects.
+assertArrayEq(coll.find({a: 1, b: 1}).returnKey().toArray(), [{}]);
+})();
+\ No newline at end of file