1 files changed, 37 insertions, 0 deletions
diff --git a/jstests/core/index_type_change.js b/jstests/core/index_type_change.js
new file mode 100644
index 00000000000..0c95828ae57
--- /dev/null
+++ b/jstests/core/index_type_change.js
@@ -0,0 +1,37 @@
+/**
+ * Tests that replacing a document with an equivalent document with different types for the fields
+ * will update the index entries associated with that document.
+ */
+
+load("jstests/libs/analyze_plan.js");  // For 'isIndexOnly'.
+
+(function() {
+    "use strict";
+
+    var coll = db.index_type_change;
+    coll.drop();
+    assert.commandWorked(coll.ensureIndex({a: 1}));
+
+    assert.writeOK(coll.insert({a: 2}));
+    assert.eq(1, coll.find({a: {$type: "double"}}).itcount());
+
+    var newVal = new NumberLong(2);
+    var res = coll.update({}, {a: newVal});  // Replacement update.
+    assert.writeOK(res);
+    assert.eq(res.nMatched, 1);
+    if (coll.getMongo().writeMode() == "commands")
+        assert.eq(res.nModified, 1);
+
+    // Make sure it actually changed the type.
+    assert.eq(1, coll.find({a: {$type: "long"}}).itcount());
+
+    // Now use a covered query to ensure the index entry has been updated.
+
+    // First make sure it's actually using a covered index scan.
+    var explain = coll.explain().find({a: 2}, {_id: 0, a: 1});
+    assert(isIndexOnly(explain));
+
+    var updated = coll.findOne({a: 2}, {_id: 0, a: 1});
+
+    assert(updated.a instanceof NumberLong, "Index entry did not change type");
+})();