1 files changed, 46 insertions, 0 deletions
diff --git a/jstests/repl/slave_sync_decimal.js b/jstests/repl/slave_sync_decimal.js
new file mode 100644
index 00000000000..dba3792cf1a
--- /dev/null
+++ b/jstests/repl/slave_sync_decimal.js
@@ -0,0 +1,46 @@
+/**
+ * Tests that we can initial sync decimal128 data to a slave, even when the cluster is in 3.2
+ * feature compatibility mode.
+ */
+(function() {
+    "use strict";
+
+    var replTest = new ReplTest("slave_sync_decimal");
+
+    var master = replTest.start(true);
+    var masterDB = master.getDB("test");
+    var masterColl = masterDB.slave_sync_decimal;
+
+    // Since the master started fresh, it should be in 3.4 feature compatibility mode.
+    var fcv = assert.commandWorked(
+        masterDB.adminCommand({getParameter: 1, featureCompatibilityVersion: 1}));
+    assert.eq(fcv.featureCompatibilityVersion, "3.4");
+
+    // Make sure we can insert decimal data in 3.4 mode.
+    assert.writeOK(masterColl.insert({a: 1, b: NumberDecimal(1)}));
+
+    // Set 3.2 feature compatibility mode.
+    assert.commandWorked(masterDB.adminCommand({setFeatureCompatibilityVersion: "3.2"}));
+    fcv = assert.commandWorked(
+        masterDB.adminCommand({getParameter: 1, featureCompatibilityVersion: 1}));
+    assert.eq(fcv.featureCompatibilityVersion, "3.2");
+
+    // We shouldn't be able to insert decimal data in 3.2 mode.
+    assert.writeError(masterColl.insert({a: 1, b: NumberDecimal(1)}));
+
+    var slave = replTest.start(false);
+    var slaveDB = slave.getDB("test");
+    var slaveColl = slaveDB.slave_sync_decimal;
+
+    fcv = assert.commandWorked(
+        slaveDB.adminCommand({getParameter: 1, featureCompatibilityVersion: 1}));
+    assert.eq(fcv.featureCompatibilityVersion, "3.2");
+
+    slave.setSlaveOk(true);
+
+    assert.soon(function() {
+        return slaveColl.find({b: NumberDecimal(1)}).itcount() === 1;
+    }, 5 * 60 * 1000, "Slave failed to sync document containing NumberDecimal");
+
+    replTest.stop();
+})();