SERVER-30084 Validate that at least one shard is present when running collectionless aggregations on mongos

1 files changed, 18 insertions, 0 deletions

diff --git a/jstests/aggregation/bugs/server30084.js b/jstests/aggregation/bugs/server30084.js
new file mode 100644
index 00000000000..926b032e229
--- /dev/null
+++ b/jstests/aggregation/bugs/server30084.js
@@ -0,0 +1,18 @@
+/**
+ * Test that running a $currentOp aggregation on a cluster with no shards returns an empty result
+ * set, and does not cause the mongoS floating point failure described in SERVER-30084.
+ */
+(function() {
+    const st = new ShardingTest({shards: 0, config: 1});
+
+    const adminDB = st.s.getDB("admin");
+
+    assert.commandWorked(
+        adminDB.runCommand({aggregate: 1, pipeline: [{$currentOp: {}}], cursor: {}}));
+    assert.commandWorked(adminDB.currentOp());
+
+    assert.eq(adminDB.aggregate([{$currentOp: {}}]).itcount(), 0);
+    assert.eq(adminDB.currentOp().inprog.length, 0);
+
+    st.stop();
+})();
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