diff --git a/src/indexer.cc b/src/indexer.cc
index e10f7dcd..3254759e 100644
--- a/src/indexer.cc
+++ b/src/indexer.cc
@@ -1220,15 +1220,18 @@ std::vector<std::unique_ptr<IndexFile>>
 Index(CompletionManager *completion, WorkingFiles *wfiles, VFS *vfs,
       const std::string &opt_wdir, const std::string &file,
       const std::vector<const char *> &args,
-      const std::vector<std::pair<std::string, std::string>> &remapped) {
+      const std::vector<std::pair<std::string, std::string>> &remapped, bool &ok) {
+  ok = true;
   if (!g_config->index.enabled)
     return {};
 
   auto PCH = std::make_shared<PCHContainerOperations>();
   llvm::IntrusiveRefCntPtr<vfs::FileSystem> FS = vfs::getRealFileSystem();
   std::shared_ptr<CompilerInvocation> CI = BuildCompilerInvocation(args, FS);
+  // e.g. .s
   if (!CI)
     return {};
+  ok = false;
   // -fparse-all-comments enables documentation in the indexer and in
   // code completion.
   CI->getLangOpts()->CommentOpts.ParseAllComments =
@@ -1288,7 +1291,6 @@ Index(CompletionManager *completion, WorkingFiles *wfiles, VFS *vfs,
   std::unique_ptr<FrontendAction> Action = createIndexingAction(
       DataConsumer, IndexOpts, std::make_unique<IndexFrontendAction>(param));
 
-  bool ok = false;
   {
     llvm::CrashRecoveryContext CRC;
     auto parse = [&]() {
diff --git a/src/indexer.h b/src/indexer.h
index 11c2b58b..b9056114 100644
--- a/src/indexer.h
+++ b/src/indexer.h
@@ -292,5 +292,6 @@ std::vector<std::unique_ptr<IndexFile>>
 Index(CompletionManager *complete, WorkingFiles *wfiles, VFS *vfs,
       const std::string &opt_wdir, const std::string &file,
       const std::vector<const char *> &args,
-      const std::vector<std::pair<std::string, std::string>> &remapped);
-}
+      const std::vector<std::pair<std::string, std::string>> &remapped,
+      bool &ok);
+} // namespace ccls::idx
diff --git a/src/pipeline.cc b/src/pipeline.cc
index f5d763ac..f31eb03d 100644
--- a/src/pipeline.cc
+++ b/src/pipeline.cc
@@ -266,10 +266,11 @@ bool Indexer_Parse(CompletionManager *completion, WorkingFiles *wfiles,
     if (content.size())
       remapped.emplace_back(path_to_index, content);
   }
+  bool ok;
   auto indexes = idx::Index(completion, wfiles, vfs, entry.directory,
-                            path_to_index, entry.args, remapped);
+                            path_to_index, entry.args, remapped, ok);
 
-  if (indexes.empty()) {
+  if (!ok) {
     if (g_config->index.enabled && request.id.Valid()) {
       Out_Error out;
       out.id = request.id;
diff --git a/src/test.cc b/src/test.cc
index d60a3bb5..7eed1af0 100644
--- a/src/test.cc
+++ b/src/test.cc
@@ -305,7 +305,8 @@ bool RunIndexTests(const std::string &filter_path, bool enable_update) {
         std::vector<const char *> cargs;
         for (auto &arg : flags)
           cargs.push_back(arg.c_str());
-        auto dbs = ccls::idx::Index(&completion, &wfiles, &vfs, "", path, cargs, {});
+        bool ok;
+        auto dbs = ccls::idx::Index(&completion, &wfiles, &vfs, "", path, cargs, {}, ok);
 
         for (const auto &entry : all_expected_output) {
           const std::string &expected_path = entry.first;