1 files changed, 38 insertions, 0 deletions
diff --git a/jstests/aggregation/bugs/server66418.js b/jstests/aggregation/bugs/server66418.js
new file mode 100644
index 00000000000..9b8c960282a
--- /dev/null
+++ b/jstests/aggregation/bugs/server66418.js
@@ -0,0 +1,38 @@
+// SERVER-66418
+// Bad projection created during dependency analysis due to string order assumption
+(function() {
+"use strict";
+
+const coll = db[jsTest.name()];
+coll.drop();
+
+coll.save({
+    _id: 1,
+    type: 'PRODUCT',
+    status: 'VALID',
+    locale: {
+        en: 'INSTRUMENT PANEL',
+        es: 'INSTRUMENTOS DEL CUADRO',
+        fr: 'INSTRUMENT TABLEAU DE BORD',
+    }
+});
+
+// before SERVER-66418, this incorrectly threw a PathCollision error
+coll.aggregate([
+    {"$match": {"_id": 1}},
+    {"$sort": {"_id": 1}},
+    {
+        "$project": {
+            "designation": {
+                "$switch": {
+                    "branches": [{
+                        "case": {"$eq": ["$type", "PRODUCT"]},
+                        "then": {"$ifNull": ["$locale.en-GB.name", "$locale.en.name"]}
+                    }],
+                    "default": {"$ifNull": ["$locale.en-GB", "$locale.en"]}
+                }
+            }
+        }
+    }
+]);
+})();