fix query errors processing (#6441)

Author: adameat

ydb/core/viewer/json_query.h

@@ -481,7 +481,7 @@ class TJsonQuery : public TViewerPipeClient<TJsonQuery> {
         NViewer::MakeErrorReply(jsonResponse, message, status);
 
         if (Span) {
-            Span.EndError("Error");
+            Span.EndError(message);
         }
     }
 

ydb/core/viewer/viewer.cpp

@@ -779,31 +779,34 @@ void MakeErrorReply(NJson::TJsonValue& jsonResponse, TString& message, const NYd
     NYql::IssuesToMessage(status.GetIssues(), &protoIssues);
 
     message.clear();
+
+    NJson::TJsonValue& jsonIssues = jsonResponse["issues"];
+    for (const auto& queryIssue : protoIssues) {
+        NJson::TJsonValue& issue = jsonIssues.AppendValue({});
+        NProtobufJson::Proto2Json(queryIssue, issue);
+    }
+
+    TString textStatus = TStringBuilder() << status.GetStatus();
+    jsonResponse["status"] = textStatus;
+
     // find first deepest error
     std::stable_sort(protoIssues.begin(), protoIssues.end(), [](const Ydb::Issue::IssueMessage& a, const Ydb::Issue::IssueMessage& b) -> bool {
         return a.severity() < b.severity();
     });
 
-    while (protoIssues.size() > 0 && protoIssues[0].issuesSize() > 0) {
-        protoIssues = protoIssues[0].issues();
+    const google::protobuf::RepeatedPtrField<Ydb::Issue::IssueMessage>* protoIssuesPtr = &protoIssues;
+    while (protoIssuesPtr->size() > 0 && protoIssuesPtr->at(0).issuesSize() > 0) {
+        protoIssuesPtr = &protoIssuesPtr->at(0).issues();
     }
 
-    if (protoIssues.size() > 0) {
-        const Ydb::Issue::IssueMessage& issue = protoIssues[0];
+    if (protoIssuesPtr->size() > 0) {
+        const Ydb::Issue::IssueMessage& issue = protoIssuesPtr->at(0);
         NProtobufJson::Proto2Json(issue, jsonResponse["error"]);
         message = issue.message();
+    } else {
+        jsonResponse["error"]["message"] = textStatus;
     }
 
-    NJson::TJsonValue& jsonIssues = jsonResponse["issues"];
-    for (const auto& queryIssue : protoIssues) {
-        NJson::TJsonValue& issue = jsonIssues.AppendValue({});
-        NProtobufJson::Proto2Json(queryIssue, issue);
-    }
-
-    TString textStatus = TStringBuilder() << status.GetStatus();
-
-    jsonResponse["status"] = textStatus;
-
     if (message.empty()) {
         message = textStatus;
     }