fix: prevent crash on KEYLOCK_ACQUIRED check for NO_KEY_TRANSACTIONAL commands

src/server/search/search_family_test.cc

@@ -2768,6 +2768,69 @@ TEST_F(SearchFamilyTest, JsonSetIndexesBug) {
   EXPECT_THAT(resp, IsUnordArrayWithSize(IsMap("text", "some text")));
 }
 
+TEST_F(SearchFamilyTest, SearchReindexWriteSearchRace) {
+  const std::string kIndexName = "myRaceIdx";
+  const int kWriterOps = 2000;    // Number of documents to write
+  const int kSearcherOps = 1500;  // Number of search operations
+  const int kReindexerOps = 25;   // Number of times to drop/recreate the index
+
+  // 1. Initial FT.CREATE for the index
+  // Schema from the issue: content TEXT SORTABLE, tags TAG SORTABLE, numeric_field NUMERIC SORTABLE
+  Run({"ft.create", kIndexName, "ON", "HASH", "PREFIX", "1", "doc:", "SCHEMA", "content", "TEXT",
+       "SORTABLE", "tags", "TAG", "SORTABLE", "numeric_field", "NUMERIC", "SORTABLE"});
+
+  // 2. writer_fiber
+  auto writer_fiber = pp_->at(0)->LaunchFiber([&] {
+    for (int i = 1; i <= kWriterOps; ++i) {
+      std::string doc_key = absl::StrCat("doc:", i);
+      std::string content = absl::StrCat("text data item ", i, " for race condition test");
+      std::string tags_val = absl::StrCat("tagA,tagB,", (i % 10));
+      std::string numeric_field_val = std::to_string(i);
+      Run({"hset", doc_key, "content", content, "tags", tags_val, "numeric_field",
+           numeric_field_val});
+      if (i % 100 == 0)
+        ThisFiber::SleepFor(std::chrono::microseconds(100));  // Brief yield
+    }
+  });
+
+  // 3. searcher_fiber
+  auto searcher_fiber = pp_->at(1)->LaunchFiber([&] {
+    for (int i = 1; i <= kSearcherOps; ++i) {
+      int random_val_content = 1 + (i % kWriterOps);
+      int random_tag_val = i % 10;
+      int random_val_numeric = 1 + (i % kWriterOps);
+
+      std::string query_content = absl::StrCat("@content:item", random_val_content);
+      std::string query_tags = absl::StrCat("@tags:{tagA|tagB|tag", random_tag_val, "}");
+      std::string query_numeric = absl::StrCat("@numeric_field:[", random_val_numeric, " ",
+                                               (random_val_numeric + 100), "]");
+      Run({"ft.search", kIndexName, query_content});
+      Run({"ft.search", kIndexName, query_tags});
+      Run({"ft.search", kIndexName, query_numeric});
+      if (i % 50 == 0)
+        ThisFiber::SleepFor(std::chrono::microseconds(200 * (1 + i % 2)));
+    }
+  });
+
+  // 4. reindexer_fiber
+  auto reindexer_fiber = pp_->at(2)->LaunchFiber([&] {
+    for (int i = 1; i <= kReindexerOps; ++i) {
+      Run({"ft.create", kIndexName, "ON", "HASH", "PREFIX", "1", "doc:", "SCHEMA", "content",
+           "TEXT", "SORTABLE", "tags", "TAG", "SORTABLE", "numeric_field", "NUMERIC", "SORTABLE"});
+      ThisFiber::SleepFor(std::chrono::milliseconds(10 + (i % 5 * 5)));
+      Run({"ft.dropindex", kIndexName});
+      ThisFiber::SleepFor(std::chrono::microseconds(500 * (1 + i % 2)));
+    }
+  });
+
+  // Join fibers
+  writer_fiber.Join();
+  searcher_fiber.Join();
+  reindexer_fiber.Join();
+
+  ASSERT_FALSE(service_->IsShardSetLocked());
+}
+
 TEST_F(SearchFamilyTest, IgnoredOptionsInFtCreate) {
   Run({"HSET", "doc:1", "title", "Test Document"});
 
@@ -2801,4 +2864,5 @@ TEST_F(SearchFamilyTest, IgnoredOptionsInFtCreate) {
   resp = Run({"FT.SEARCH", "idx", "*"});
   EXPECT_THAT(resp, AreDocIds("doc:1"));
 }
+
 }  // namespace dfly

src/server/transaction.cc

@@ -1245,9 +1245,16 @@ bool Transaction::CancelShardCb(EngineShard* shard) {
     shard->shard_lock()->Release(LockMode());
   } else {
     auto lock_args = GetLockArgs(shard->shard_id());
-    DCHECK(sd.local_mask & KEYLOCK_ACQUIRED);
-    DCHECK(!lock_args.fps.empty());
-    GetDbSlice(shard->shard_id()).Release(LockMode(), lock_args);
+
+    if (lock_args.fps.empty()) {
+      // For NO_KEY_TRANSACTIONAL commands, we don't need to release locks
+      // because we don't acquire locks for them.
+      DCHECK(cid_->opt_mask() & CO::NO_KEY_TRANSACTIONAL);
+    } else {
+      DCHECK(sd.local_mask & KEYLOCK_ACQUIRED);
+      GetDbSlice(shard->shard_id()).Release(LockMode(), lock_args);
+    }
+
     sd.local_mask &= ~KEYLOCK_ACQUIRED;
   }