From d2d8006037b891b30c141a008ce968f77193c224 Mon Sep 17 00:00:00 2001
From: Alexey Milovidov <milovidov@clickhouse.com>
Date: Mon, 17 Jun 2024 04:57:16 +0200
Subject: [PATCH] Fix error

---
 src/Parsers/TokenIterator.h | 14 +++++++++++++-
 src/Parsers/parseQuery.cpp  | 10 +++++++---
 2 files changed, 20 insertions(+), 4 deletions(-)

diff --git a/src/Parsers/TokenIterator.h b/src/Parsers/TokenIterator.h
index 207ddadb8bf..0d18ee5439e 100644
--- a/src/Parsers/TokenIterator.h
+++ b/src/Parsers/TokenIterator.h
@@ -21,6 +21,7 @@ class Tokens
 {
 private:
     std::vector<Token> data;
+    size_t max_pos = 0;
     Lexer lexer;
     bool skip_insignificant;
 
@@ -35,10 +36,16 @@ public:
         while (true)
         {
             if (index < data.size())
+            {
+                max_pos = std::max(max_pos, index);
                 return data[index];
+            }
 
             if (!data.empty() && data.back().isEnd())
+            {
+                max_pos = data.size() - 1;
                 return data.back();
+            }
 
             Token token = lexer.nextToken();
 
@@ -51,7 +58,12 @@ public:
     {
         if (data.empty())
             return (*this)[0];
-        return data.back();
+        return data[max_pos];
+    }
+
+    void reset()
+    {
+        max_pos = 0;
     }
 };
 
diff --git a/src/Parsers/parseQuery.cpp b/src/Parsers/parseQuery.cpp
index df9664060b3..a917722c92c 100644
--- a/src/Parsers/parseQuery.cpp
+++ b/src/Parsers/parseQuery.cpp
@@ -285,6 +285,8 @@ ASTPtr tryParseQuery(
         return nullptr;
     }
 
+    Expected expected;
+
     /** A shortcut - if Lexer found invalid tokens, fail early without full parsing.
       * But there are certain cases when invalid tokens are permitted:
       * 1. INSERT queries can have arbitrary data after the FORMAT clause, that is parsed by a different parser.
@@ -293,9 +295,9 @@ ASTPtr tryParseQuery(
       *
       * This shortcut is needed to avoid complex backtracking in case of obviously erroneous queries.
       */
-    IParser::Pos lookahead = token_iterator;
-    if (!ParserKeyword(Keyword::INSERT_INTO).ignore(lookahead))
+    if (!ParserKeyword(Keyword::INSERT_INTO).check(token_iterator, expected))
     {
+        IParser::Pos lookahead(token_iterator);
         while (lookahead->type != TokenType::Semicolon && lookahead->type != TokenType::EndOfStream)
         {
             if (lookahead->isError())
@@ -306,9 +308,11 @@ ASTPtr tryParseQuery(
 
             ++lookahead;
         }
+
+        /// We should not spoil the info about maximum parsed position in the original iterator.
+        tokens.reset();
     }
 
-    Expected expected;
     ASTPtr res;
     const bool parse_res = parser.parse(token_iterator, res, expected);
     const auto last_token = token_iterator.max();