clickhouse-client: add echoOn/echoOff hints

programs/client/Client.cpp

@@ -1110,8 +1110,7 @@ private:
 
             // Echo all queries if asked; makes for a more readable reference
             // file.
-            if (test_hint.echoQueries())
-                echo_queries_ = true;
+            echo_queries_ = test_hint.echoQueries().value_or(echo_queries_);
 
             try
             {

programs/client/TestHint.h

@@ -59,13 +59,13 @@ public:
 
     int serverError() const { return server_error; }
     int clientError() const { return client_error; }
-    bool echoQueries() const { return echo; }
+    std::optional<bool> echoQueries() const { return echo; }
 
 private:
     const String & query;
     int server_error = 0;
     int client_error = 0;
-    bool echo = false;
+    std::optional<bool> echo;
 
     void parse(const String & hint, bool is_leading_hint)
     {
@@ -88,7 +88,11 @@ private:
             }
 
             if (item == "echo")
-                echo = true;
+                echo.emplace(true);
+            if (item == "echoOn")
+                echo.emplace(true);
+            if (item == "echoOff")
+                echo.emplace(false);
         }
     }
 

tests/queries/0_stateless/01891_echo.reference

@@ -2,3 +2,7 @@
 -- { echo }
 select 1;
 1
+2
+-- { echoOn }
+select 2;
+2

tests/queries/0_stateless/01891_echo.sql

@@ -1,3 +1,7 @@
 select 1;
 -- { echo }
 select 1;
+-- { echoOff }
+select 2;
+-- { echoOn }
+select 2;