SERVER-30665 Only accept nonexistent UUIDs for UUID upgrade collMods

2 files changed, 67 insertions, 14 deletions

diff --git a/jstests/noPassthrough/coll_mod_apply_ops.js b/jstests/noPassthrough/coll_mod_apply_ops.js
new file mode 100644
index 00000000000..5755e1ddf30
--- /dev/null
+++ b/jstests/noPassthrough/coll_mod_apply_ops.js
@@ -0,0 +1,43 @@
+// SERVER-30665 Ensure that a non-empty collMod with a nonexistent UUID is not applied
+// in applyOps.
+
+(function() {
+    "use strict";
+    const conn = MongoRunner.runMongod();
+    assert.neq(null, conn, "mongod was unable to start up with empty options");
+
+    let dbCollModName = "db_coll_mod";
+    const dbCollMod = conn.getDB(dbCollModName);
+    dbCollMod.dropDatabase();
+    let collName = "collModTest";
+    let coll = dbCollMod[collName];
+
+    // Generate a random UUID that is distinct from collModTest's UUID.
+    const randomUUID = UUID();
+    assert.neq(randomUUID, coll.uuid);
+
+    // Perform a collMod to initialize validationLevel to "off".
+    assert.commandWorked(dbCollMod.createCollection(collName));
+    let cmd = {"collMod": collName, "validationLevel": "off"};
+    let res = dbCollMod.runCommand(cmd);
+    assert.commandWorked(res, 'could not run ' + tojson(cmd));
+    let collectionInfosOriginal = dbCollMod.getCollectionInfos()[0];
+    assert.eq(collectionInfosOriginal.options.validationLevel, "off");
+
+    // Perform an applyOps command with a nonexistent UUID and the same name as an existing
+    // collection. applyOps should succeed because of idempotency but a NamespaceNotFound
+    // uassert should be thrown during collMod application.
+    let collModApplyOpsEntry = {
+        "v": 2,
+        "op": "c",
+        "ns": dbCollModName + ".$cmd",
+        "ui": randomUUID,
+        "o2": {"collectionOptions_old": {"uuid": randomUUID}},
+        "o": {"collMod": collName, "validationLevel": "moderate"}
+    };
+    assert.commandWorked(dbCollMod.adminCommand({"applyOps": [collModApplyOpsEntry]}));
+
+    // Ensure the collection options of the existing collection were not affected.
+    assert.eq(dbCollMod.getCollectionInfos()[0].name, collName);
+    assert.eq(dbCollMod.getCollectionInfos()[0].options.validationLevel, "off");
+}());
diff --git a/src/mongo/db/repl/oplog.cpp b/src/mongo/db/repl/oplog.cpp
index e7e6de49b11..d8877504c04 100644
--- a/src/mongo/db/repl/oplog.cpp
+++ b/src/mongo/db/repl/oplog.cpp
@@ -624,6 +624,29 @@ NamespaceString parseNs(const string& ns, const BSONObj& cmdObj) {
     return NamespaceString(NamespaceString(ns).db().toString(), coll);
 }
 
+std::pair<OptionalCollectionUUID, NamespaceString> parseCollModUUIDAndNss(OperationContext* opCtx,
+                                                                          const BSONElement& ui,
+                                                                          const char* ns,
+                                                                          BSONObj& cmd) {
+    if (ui.eoo()) {
+        return std::pair<OptionalCollectionUUID, NamespaceString>(boost::none, parseNs(ns, cmd));
+    }
+    CollectionUUID uuid = uassertStatusOK(UUID::parse(ui));
+    auto& catalog = UUIDCatalog::get(opCtx);
+    if (catalog.lookupCollectionByUUID(uuid)) {
+        return std::pair<OptionalCollectionUUID, NamespaceString>(uuid,
+                                                                  catalog.lookupNSSByUUID(uuid));
+    } else {
+        uassert(ErrorCodes::NamespaceNotFound,
+                str::stream() << "Failed to apply operation due to missing collection (" << uuid
+                              << "): "
+                              << redact(cmd.toString()),
+                cmd.nFields() == 1);
+        // If cmd is an empty collMod, i.e., nFields is 1, this is a UUID upgrade collMod.
+        return std::pair<OptionalCollectionUUID, NamespaceString>(uuid, parseNs(ns, cmd));
+    }
+}
+
 NamespaceString parseUUID(OperationContext* opCtx, const BSONElement& ui) {
     auto statusWithUUID = UUID::parse(ui);
     uassertStatusOK(statusWithUUID);
@@ -715,22 +738,9 @@ std::map<std::string, ApplyOpMetadata> opsMap = {
          const BSONElement& ui,
          BSONObj& cmd,
          const OpTime& opTime) -> Status {
-          // Get UUID from cmd, if it exists.
           OptionalCollectionUUID uuid;
           NamespaceString nss;
-          if (ui.eoo()) {
-              uuid = boost::none;
-              nss = parseNs(ns, cmd);
-          } else {
-              uuid = uassertStatusOK(UUID::parse(ui));
-              // We need to see whether a collection with UUID ui exists before attempting to do
-              // a collMod on it. This is because we add UUIDs during upgrade to
-              // featureCompatibilityVersion 3.6 with a collMod command, so the collection will
-              // not have a UUID at the time we attempt to look it up by UUID.
-              auto& catalog = UUIDCatalog::get(opCtx);
-              nss = catalog.lookupCollectionByUUID(uuid.get()) ? catalog.lookupNSSByUUID(uuid.get())
-                                                               : parseNs(ns, cmd);
-          }
+          std::tie(uuid, nss) = parseCollModUUIDAndNss(opCtx, ui, ns, cmd);
           return collModForUUIDUpgrade(opCtx, nss, cmd, uuid);
       },
       {ErrorCodes::IndexNotFound, ErrorCodes::NamespaceNotFound}}},