1 files changed, 67 insertions, 9 deletions
diff --git a/jstests/multiVersion/internal_transactions_index_setFCV.js b/jstests/multiVersion/internal_transactions_index_setFCV.js
index 712e8249a54..a3ce2ead44a 100644
--- a/jstests/multiVersion/internal_transactions_index_setFCV.js
+++ b/jstests/multiVersion/internal_transactions_index_setFCV.js
@@ -41,7 +41,8 @@ function assertPartialIndexDoesNotExist(node) {
  * Verifies the partial index is dropped/created on FCV transitions and retryable writes work in all
  * FCVs.
  */
-function runTest(setFCVConn, modifyIndexConns, verifyIndexConns, rst) {
+function runTest(
+    setFCVConn, modifyIndexConns, verifyIndexConns, rst, alwaysCreateFeatureFlagEnabled) {
     // Start at latest FCV which should have the index.
     assert.commandWorked(setFCVConn.adminCommand({setFeatureCompatibilityVersion: latestFCV}));
     verifyIndexConns.forEach(conn => {
@@ -54,8 +55,12 @@ function runTest(setFCVConn, modifyIndexConns, verifyIndexConns, rst) {
         assertPartialIndexDoesNotExist(conn);
     });
 
+    assert.commandWorked(setFCVConn.getDB("foo").runCommand(
+        {insert: "bar", documents: [{x: 1}], lsid: {id: UUID()}, txnNumber: NumberLong(11)}));
+
     if (rst) {
-        // On step up to primary the index should not be created.
+        // On step up to primary the index should not be created. Note this tests the empty
+        // collection case when alwaysCreateFeatureFlagEnabled is true.
 
         let primary = rst.getPrimary();
         // Clear the collection so we'd try to create the index.
@@ -69,8 +74,21 @@ function runTest(setFCVConn, modifyIndexConns, verifyIndexConns, rst) {
         rst.awaitReplication();
         verifyIndexConns.forEach(conn => {
             reconnect(conn);
-            assertPartialIndexDoesNotExist(conn);
+            if (alwaysCreateFeatureFlagEnabled) {
+                assertPartialIndexExists(conn);
+            } else {
+                assertPartialIndexDoesNotExist(conn);
+            }
         });
+
+        if (alwaysCreateFeatureFlagEnabled) {
+            // The test expects no index after this block, so remove it.
+            modifyIndexConns.forEach(conn => {
+                assert.commandWorked(
+                    conn.getCollection("config.transactions").dropIndex("parent_lsid"));
+            });
+        }
+        rst.awaitReplication();
     }
 
     assert.commandWorked(setFCVConn.getDB("foo").runCommand(
@@ -93,11 +111,15 @@ function runTest(setFCVConn, modifyIndexConns, verifyIndexConns, rst) {
     });
 
     if (rst) {
-        // On step up to primary the index should not be created.
+        // On step up to primary the index should not be created. Note this tests the non-empty
+        // collection case when alwaysCreateFeatureFlagEnabled is true.
 
         let primary = rst.getPrimary();
-        // Clear the collection so we'd try to create the index.
-        assert.commandWorked(primary.getDB("config").transactions.remove({}));
+        // Clear the collection so we'd try to create the index. Skip if the always create index
+        // feature flag is on because we'd try to create the index anyway.
+        if (!alwaysCreateFeatureFlagEnabled) {
+            assert.commandWorked(primary.getDB("config").transactions.remove({}));
+        }
         assert.commandWorked(
             primary.adminCommand({replSetStepDown: ReplSetTest.kForeverSecs, force: true}));
         assert.commandWorked(primary.adminCommand({replSetFreeze: 0}));
@@ -107,8 +129,21 @@ function runTest(setFCVConn, modifyIndexConns, verifyIndexConns, rst) {
         rst.awaitReplication();
         verifyIndexConns.forEach(conn => {
             reconnect(conn);
-            assertPartialIndexDoesNotExist(conn);
+            if (alwaysCreateFeatureFlagEnabled) {
+                assertPartialIndexExists(conn);
+            } else {
+                assertPartialIndexDoesNotExist(conn);
+            }
         });
+
+        if (alwaysCreateFeatureFlagEnabled) {
+            // The test expects no index after this block, so remove it.
+            modifyIndexConns.forEach(conn => {
+                assert.commandWorked(
+                    conn.getCollection("config.transactions").dropIndex("parent_lsid"));
+            });
+        }
+        rst.awaitReplication();
     }
 
     assert.commandWorked(setFCVConn.getDB("foo").runCommand(
@@ -124,8 +159,11 @@ function runTest(setFCVConn, modifyIndexConns, verifyIndexConns, rst) {
         // On step up to primary the index should be created.
 
         let primary = rst.getPrimary();
-        // Clear the collection so we'll try to create the index.
-        assert.commandWorked(primary.getDB("config").transactions.remove({}));
+        // Clear the collection so we'd try to create the index. Skip if the always create index
+        // feature flag is on because we'd try to create the index anyway.
+        if (!alwaysCreateFeatureFlagEnabled) {
+            assert.commandWorked(primary.getDB("config").transactions.remove({}));
+        }
         assert.commandWorked(
             primary.adminCommand({replSetStepDown: ReplSetTest.kForeverSecs, force: true}));
         assert.commandWorked(primary.adminCommand({replSetFreeze: 0}));
@@ -193,6 +231,26 @@ function runTest(setFCVConn, modifyIndexConns, verifyIndexConns, rst) {
 }
 
 {
+    // Enabling featureFlagAlwaysCreateConfigTransactionsPartialIndexOnStepUp should not lead to
+    // creating the index if the internal transactions feature flag is not enabled.
+    const featureFlagRst = new ReplSetTest({
+        nodes: 2,
+        nodeOptions:
+            {setParameter: "featureFlagAlwaysCreateConfigTransactionsPartialIndexOnStepUp=true"}
+    });
+    featureFlagRst.startSet();
+    featureFlagRst.initiate();
+    // Note setFCV always waits for majority write concern so in a two node cluster secondaries will
+    // always have replicated the setFCV writes.
+    runTest(featureFlagRst.getPrimary(),
+            [featureFlagRst.getPrimary()],
+            [featureFlagRst.getPrimary(), featureFlagRst.getSecondary()],
+            featureFlagRst,
+            true /* alwaysCreateFeatureFlagEnabled */);
+    featureFlagRst.stopSet();
+}
+
+{
     const conn = MongoRunner.runMongod();
 
     const configTxnsCollection = conn.getCollection("config.transactions");