SERVER-74270 Allow changeStreamPreAndPostImages collection option on config server nodes

1 files changed, 41 insertions, 0 deletions

diff --git a/jstests/multiVersion/targetedTestsLastLtsFeatures/cannot_downgrade_config_server_with_change_streams_images_collection_option.js b/jstests/multiVersion/targetedTestsLastLtsFeatures/cannot_downgrade_config_server_with_change_streams_images_collection_option.js
new file mode 100644
index 00000000000..4c7e3fda8a9
--- /dev/null
+++ b/jstests/multiVersion/targetedTestsLastLtsFeatures/cannot_downgrade_config_server_with_change_streams_images_collection_option.js
@@ -0,0 +1,41 @@
+/**
+ * Verifies a config server cannot downgrade with a collection with changeStreamPreAndPostImages
+ * enabled.
+ *
+ * @tags: [featureFlagCatalogShard]
+ */
+(function() {
+"use strict";
+
+const st = new ShardingTest({config: 1, shards: 1});
+
+// A collection on a shard with changeStreamPreAndPostImages shouldn't impact downgrade.
+const validShardNS = "foo.bar";
+assert.commandWorked(st.s.getCollection(validShardNS).insert({x: 1}));
+assert.commandWorked(
+    st.s.getDB("foo").runCommand({collMod: "bar", changeStreamPreAndPostImages: {enabled: true}}));
+
+// A collection on the config server with changeStreamPreAndPostImages should prevent downgrade. The
+// config server can only downgrade when in dedicated mode and in this mode the only user
+// accessible collections on it are in the config and admin databases, which never allow this
+// option, so we have to create a collection on a separate db via direct connection.
+const directConfigNS = "directDB.onConfig";
+assert.commandWorked(st.configRS.getPrimary().getCollection(directConfigNS).insert({x: 1}));
+assert.commandWorked(st.configRS.getPrimary().getDB("directDB").runCommand({
+    collMod: "onConfig",
+    changeStreamPreAndPostImages: {enabled: true}
+}));
+
+assert.commandFailedWithCode(st.s.adminCommand({setFeatureCompatibilityVersion: lastLTSFCV}),
+                             ErrorCodes.CannotDowngrade);
+
+// Unset the option on the config server collection and now the config server can downgrade.
+assert.commandWorked(st.configRS.getPrimary().getDB("directDB").runCommand({
+    collMod: "onConfig",
+    changeStreamPreAndPostImages: {enabled: false}
+}));
+
+assert.commandWorked(st.s.adminCommand({setFeatureCompatibilityVersion: lastLTSFCV}));
+
+st.stop();
+})();