SERVER-68477 TTL monitor skips indexes with NaN expireAfterSeconds

(cherry-picked from commit 14c07b53186ee88497abd0ba492d2d9157891718)

(cherry picked from commit 7d76329f8915ec80ba07c07e4a0adbc7fd187107)
(cherry picked from commit 0f56fdb4c92f6728a8560469e66f4432fabc468d)

2 files changed, 50 insertions, 2 deletions

diff --git a/jstests/noPassthrough/ttl_expire_nan.js b/jstests/noPassthrough/ttl_expire_nan.js
new file mode 100644
index 00000000000..5d26b214487
--- /dev/null
+++ b/jstests/noPassthrough/ttl_expire_nan.js
@@ -0,0 +1,45 @@
+/**
+ * Tests TTL indexes with NaN for 'expireAfterSeconds'.
+ *
+ * Existing TTL indexes from older versions of the server may contain a NaN for the duration.
+ * Newer server versions (5.0+) normalize the TTL duration to 0.
+ *
+ * @tags: [
+ *     requires_replication,
+ * ]
+ */
+(function() {
+'use strict';
+
+const rst = new ReplSetTest({
+    nodes: [{}, {rsConfig: {votes: 0, priority: 0}}],
+    nodeOptions: {setParameter: {ttlMonitorSleepSecs: 5}},
+});
+rst.startSet();
+rst.initiate();
+
+let primary = rst.getPrimary();
+const db = primary.getDB('test');
+const coll = db.t;
+
+assert.commandWorked(coll.createIndex({t: 1}, {expireAfterSeconds: NaN}));
+assert.commandWorked(coll.insert({_id: 0, t: ISODate()}));
+
+// Wait for "TTL indexes require the expire field to be numeric, skipping TTL job" log message.
+checkLog.containsJson(primary, 22542, {ns: coll.getFullName()});
+
+// TTL index should be replicated to the secondary with a NaN 'expireAfterSeconds'.
+const secondary = rst.getSecondary();
+checkLog.containsJson(secondary, 20384, {
+    namespace: coll.getFullName(),
+    properties: (spec) => {
+        jsTestLog('TTL index on secondary: ' + tojson(spec));
+        return isNaN(spec.expireAfterSeconds);
+    }
+});
+
+assert.eq(
+    coll.countDocuments({}), 1, 'ttl index with NaN duration should not remove any documents.');
+
+rst.stopSet();
+})();
diff --git a/src/mongo/db/ttl.cpp b/src/mongo/db/ttl.cpp
index c682282100f..7e02d6816d0 100644
--- a/src/mongo/db/ttl.cpp
+++ b/src/mongo/db/ttl.cpp
@@ -376,9 +376,12 @@ private:
         }
 
         BSONElement secondsExpireElt = spec[IndexDescriptor::kExpireAfterSecondsFieldName];
-        if (!secondsExpireElt.isNumber()) {
+        if (!secondsExpireElt.isNumber() || secondsExpireElt.isNaN()) {
             LOGV2_ERROR(22542,
-                        "TTL indexes require the expire field to be numeric, skipping TTL job",
+                        "TTL indexes require the expire field to be numeric and not a NaN, "
+                        "skipping TTL job",
+                        "ns"_attr = collection->ns(),
+                        "uuid"_attr = collection->uuid(),
                         "field"_attr = IndexDescriptor::kExpireAfterSecondsFieldName,
                         "type"_attr = typeName(secondsExpireElt.type()),
                         "index"_attr = spec);