SERVER-5972 Allow `system.js` to be dropped

3 files changed, 42 insertions, 1 deletions

diff --git a/jstests/core/system_js_drop.js b/jstests/core/system_js_drop.js
new file mode 100644
index 00000000000..49a59c14ed5
--- /dev/null
+++ b/jstests/core/system_js_drop.js
@@ -0,0 +1,37 @@
+/**
+ * Tests dropping the system.js collection.
+ *
+ * @tags: [
+ *   assumes_read_preference_unchanged,
+ *   assumes_unsharded_collection,
+ *   requires_fcv_62,
+ *   requires_non_retryable_writes,
+ * ]
+ */
+(function() {
+'use strict';
+
+const testDB = db.getSiblingDB(jsTestName());
+assert.commandWorked(testDB.dropDatabase());
+
+const coll = testDB.coll;
+const systemJs = testDB.system.js;
+
+assert.commandWorked(coll.insert([{name: 'Alice', age: 20}, {name: 'Bob', age: 18}]));
+
+assert.commandWorked(systemJs.insert({
+    _id: "isTeenager",
+    value: function(age) {
+        return age >= 13 && age <= 19;
+    },
+}));
+
+assert.commandWorked(
+    testDB.runCommand({find: coll.getName(), filter: {$where: "isTeenager(this.age)"}}));
+
+assert(systemJs.drop());
+
+assert.commandFailedWithCode(
+    testDB.runCommand({find: coll.getName(), filter: {$where: "isTeenager(this.age)"}}),
+    ErrorCodes.JSInterpreterFailure);
+})();
diff --git a/src/mongo/db/catalog/database_impl.cpp b/src/mongo/db/catalog/database_impl.cpp
index dfa0d846762..28c3fa2e8cb 100644
--- a/src/mongo/db/catalog/database_impl.cpp
+++ b/src/mongo/db/catalog/database_impl.cpp
@@ -423,7 +423,8 @@ Status DatabaseImpl::dropCollection(OperationContext* opCtx,
             nss == NamespaceString::kKeysCollectionNamespace ||
             nss.isTemporaryReshardingCollection() || nss.isTimeseriesBucketsCollection() ||
             nss.isChangeStreamPreImagesCollection() ||
-            nss == NamespaceString::kConfigsvrRestoreNamespace || nss.isChangeCollection();
+            nss == NamespaceString::kConfigsvrRestoreNamespace || nss.isChangeCollection() ||
+            nss.isSystemDotJavascript();
     };
 
     if (nss.isSystem()) {
diff --git a/src/mongo/db/op_observer/op_observer_impl.cpp b/src/mongo/db/op_observer/op_observer_impl.cpp
index 00f0ddc253d..7350a487db8 100644
--- a/src/mongo/db/op_observer/op_observer_impl.cpp
+++ b/src/mongo/db/op_observer/op_observer_impl.cpp
@@ -1357,6 +1357,9 @@ repl::OpTime OpObserverImpl::onDropCollection(OperationContext* opCtx,
         ReadWriteConcernDefaults::get(opCtx).invalidate();
     } else if (collectionName.isTimeseriesBucketsCollection()) {
         BucketCatalog::get(opCtx).clear(collectionName.getTimeseriesViewNamespace());
+    } else if (collectionName.isSystemDotJavascript()) {
+        // Inform the JavaScript engine of the change to system.js.
+        Scope::storedFuncMod(opCtx);
     }
 
     return {};