1 files changed, 41 insertions, 0 deletions
diff --git a/jstests/aggregation/sources/lookup/lookup_random.js b/jstests/aggregation/sources/lookup/lookup_random.js
new file mode 100644
index 00000000000..3558e1d6061
--- /dev/null
+++ b/jstests/aggregation/sources/lookup/lookup_random.js
@@ -0,0 +1,41 @@
+// Operators that use a random generator ($sample and $rand) are not allowed to be cached
+// as part of a non-correlated prefix.
+// @tags: [assumes_unsharded_collection]
+(function() {
+"use strict";
+
+const coll = db.getCollection('lookup_random');
+coll.drop();
+assert.commandWorked(coll.insert(Array.from({length: 200}, (_, i) => ({_id: i}))));
+
+// $sample in the inner pipeline should be rerun per outer document.
+let result = coll.aggregate([
+    {$lookup: {
+        from: coll.getName(),
+        as: 'docs',
+        pipeline: [
+            {$sample: {size: 1}},
+        ],
+    }},
+    {$unwind: "$docs"},
+    {$group: {_id: null, sampled: {$addToSet: "$docs._id"}}},
+]).toArray();
+assert.eq(result.length, 1, result);
+assert.gt(result[0].sampled.length, 1, result);
+
+// $rand in the inner pipeline should be rerun per outer document.
+result = coll.aggregate([
+    {$lookup: {
+        from: coll.getName(),
+        as: 'docs',
+        pipeline: [
+            {$limit: 1},
+            {$set: {r: {$rand: {}}}},
+        ],
+    }},
+    {$unwind: "$docs"},
+    {$group: {_id: null, randomValues: {$addToSet: "$docs.r"}}},
+]).toArray();
+assert.eq(result.length, 1, result);
+assert.gt(result[0].randomValues.length, 1, result);
+})();