Bug#15518 Reusing a stmt that has failed during prepare does not clear error

 - Always reset error when calling mysql_stmt_prepare a second time
 - Set stmt->state to MYSQL_STMT_INIT_DONE before closing prepared stmt in server.
 - Add test to mysql_client_test
 - Remove mysql_stmt_close in mysqltest after each query
 - Close all open statements in mysqltest if disable_ps_protocol is called. 


client/mysqltest.c:
  Don't close the statement after each query - reprepare it in next query.
  When "disable_ps_protocol" is issued make sure to close all open
  statements. Otherwise the test for @@max_prepared_statements fails. But we
  also get a test that the statements that are open can be closed and reopened
  in the middle of the tests.
libmysql/libmysql.c:
  Reset the last error every time mysql_stmt_prepare is called.
  Set state to MYSQL_STMT_INIT_DONE befoe closing it in the server. That way
  we will always have right status regardless of wheter close fails or not.
tests/mysql_client_test.c:
  Add testcase for bug15518, re-prepare a previously prepare statement that has failed
  to prepare. Test also when connection to server has been lost inbetween.
  Change all assert to DIE_UNLESS so we get printout of line and an error message
  if it fails.

client/mysqltest.c

@@ -719,6 +719,20 @@ void close_connections()
 }
 
 
+void close_statements()
+{
+  struct st_connection *con;
+  DBUG_ENTER("close_statements");
+  for (con= connections; con < next_con; con++)
+  {
+    if (con->stmt)
+      mysql_stmt_close(con->stmt);
+    con->stmt= 0;
+  }
+  DBUG_VOID_RETURN;
+}
+
+
 void close_files()
 {
   DBUG_ENTER("close_files");
@@ -2855,6 +2869,10 @@ void do_close_connection(struct st_command *command)
 	}
       }
 #endif
+      if (next_con->stmt)
+        mysql_stmt_close(next_con->stmt);
+      next_con->stmt= 0;
+
       mysql_close(&con->mysql);
       if (con->util_mysql)
 	mysql_close(con->util_mysql);
@@ -5050,10 +5068,7 @@ end:
   */
 
   var_set_errno(mysql_stmt_errno(stmt));
-#ifndef BUG15518_FIXED
-  mysql_stmt_close(stmt);
-  cur_con->stmt= NULL;
-#endif
+
   DBUG_VOID_RETURN;
 }
 
@@ -5838,6 +5853,8 @@ int main(int argc, char **argv)
 	break;
       case Q_DISABLE_PS_PROTOCOL:
         ps_protocol_enabled= 0;
+        /* Close any open statements */
+        close_statements();
         break;
       case Q_ENABLE_PS_PROTOCOL:
         ps_protocol_enabled= ps_protocol;

libmysql/libmysql.c

@@ -2038,6 +2038,13 @@ mysql_stmt_prepare(MYSQL_STMT *stmt, const char *query, ulong length)
     DBUG_RETURN(1);
   }
 
+  /*
+    Reset the last error in any case: that would clear the statement
+    if the previous prepare failed.
+  */
+  stmt->last_errno= 0;
+  stmt->last_error[0]= '\0';
+
   if ((int) stmt->state > (int) MYSQL_STMT_INIT_DONE)
   {
     /* This is second prepare with another statement */
@@ -2051,23 +2058,24 @@ mysql_stmt_prepare(MYSQL_STMT *stmt, const char *query, ulong length)
     */
     stmt->bind_param_done= stmt->bind_result_done= FALSE;
     stmt->param_count= stmt->field_count= 0;
-    stmt->last_errno= 0;
-    stmt->last_error[0]= '\0';
     free_root(&stmt->mem_root, MYF(MY_KEEP_PREALLOC));
 
     int4store(buff, stmt->stmt_id);
+
     /*
+      Close statement in server
+
       If there was a 'use' result from another statement, or from
       mysql_use_result it won't be freed in mysql_stmt_free_result and
       we should get 'Commands out of sync' here.
     */
+    stmt->state= MYSQL_STMT_INIT_DONE;
     if (stmt_command(mysql, COM_STMT_CLOSE, buff, 4, stmt))
     {
       set_stmt_errmsg(stmt, mysql->net.last_error, mysql->net.last_errno,
                       mysql->net.sqlstate);
       DBUG_RETURN(1);
     }
-    stmt->state= MYSQL_STMT_INIT_DONE;
   }
 
   if (stmt_command(mysql, COM_STMT_PREPARE, query, length, stmt))

tests/mysql_client_test.c

@@ -11014,7 +11014,7 @@ static void test_view()
     rc= mysql_stmt_execute(stmt);
     check_execute(stmt, rc);
     rc= my_process_stmt_result(stmt);
-    assert(1 == rc);
+    DIE_UNLESS(1 == rc);
   }
   mysql_stmt_close(stmt);
 
@@ -11057,7 +11057,7 @@ static void test_view_where()
     rc= mysql_stmt_execute(stmt);
     check_execute(stmt, rc);
     rc= my_process_stmt_result(stmt);
-    assert(4 == rc);
+    DIE_UNLESS(4 == rc);
   }
   mysql_stmt_close(stmt);
 
@@ -11140,7 +11140,7 @@ static void test_view_2where()
   rc= mysql_stmt_execute(stmt);
   check_execute(stmt, rc);
   rc= my_process_stmt_result(stmt);
-  assert(0 == rc);
+  DIE_UNLESS(0 == rc);
 
   mysql_stmt_close(stmt);
 
@@ -11193,7 +11193,7 @@ static void test_view_star()
     rc= mysql_stmt_execute(stmt);
     check_execute(stmt, rc);
     rc= my_process_stmt_result(stmt);
-    assert(0 == rc);
+    DIE_UNLESS(0 == rc);
   }
 
   mysql_stmt_close(stmt);
@@ -11256,7 +11256,7 @@ static void test_view_insert()
     rc= mysql_stmt_execute(select_stmt);
     check_execute(select_stmt, rc);
     rowcount= (int)my_process_stmt_result(select_stmt);
-    assert((i+1) == rowcount);
+    DIE_UNLESS((i+1) == rowcount);
   }
   mysql_stmt_close(insert_stmt);
   mysql_stmt_close(select_stmt);
@@ -11297,7 +11297,7 @@ static void test_left_join_view()
     rc= mysql_stmt_execute(stmt);
     check_execute(stmt, rc);
     rc= my_process_stmt_result(stmt);
-    assert(3 == rc);
+    DIE_UNLESS(3 == rc);
   }
   mysql_stmt_close(stmt);
 
@@ -11373,7 +11373,7 @@ static void test_view_insert_fields()
   rc= mysql_stmt_execute(stmt);
   check_execute(stmt, rc);
   rc= my_process_stmt_result(stmt);
-  assert(1 == rc);
+  DIE_UNLESS(1 == rc);
 
   mysql_stmt_close(stmt);
   rc= mysql_query(mysql, "DROP VIEW v1");
@@ -12851,6 +12851,82 @@ static void test_bug7990()
   DIE_UNLESS(!mysql_errno(mysql));
 }
 
+/*
+  Bug #15518 - Reusing a stmt that has failed during prepare
+  does not clear error
+*/
+
+static void test_bug15518()
+{
+  MYSQL_STMT *stmt;
+  MYSQL* mysql1;
+  int rc;
+  myheader("test_bug15518");
+
+  mysql1= mysql_init(NULL);
+
+  if (!mysql_real_connect(mysql1, opt_host, opt_user, opt_password,
+                          opt_db ? opt_db : "test", opt_port, opt_unix_socket,
+                          CLIENT_MULTI_STATEMENTS))
+  {
+    fprintf(stderr, "Failed to connect to the database\n");
+    DIE_UNLESS(0);
+  }
+
+  stmt= mysql_stmt_init(mysql1);
+
+  /*
+    The prepare of foo should fail with errno 1064 since
+    it's not a valid query
+  */
+  rc= mysql_stmt_prepare(stmt, "foo", 3);
+  if (!opt_silent)
+    fprintf(stdout, "rc: %d, mysql_stmt_errno: %d, mysql_errno: %d\n",
+            rc, mysql_stmt_errno(stmt), mysql_errno(mysql1));
+  DIE_UNLESS(rc && mysql_stmt_errno(stmt) && mysql_errno(mysql1));
+
+  /*
+    Use the same stmt and reprepare with another query that
+    suceeds
+  */
+  rc= mysql_stmt_prepare(stmt, "SHOW STATUS", 12);
+  if (!opt_silent)
+    fprintf(stdout, "rc: %d, mysql_stmt_errno: %d, mysql_errno: %d\n",
+            rc, mysql_stmt_errno(stmt), mysql_errno(mysql1));
+  DIE_UNLESS(!rc || mysql_stmt_errno(stmt) || mysql_errno(mysql1));
+
+  mysql_stmt_close(stmt);
+  DIE_UNLESS(!mysql_errno(mysql1));
+
+  /*
+    part2, when connection to server has been closed
+    after first prepare
+  */
+  stmt= mysql_stmt_init(mysql1);
+  rc= mysql_stmt_prepare(stmt, "foo", 3);
+  if (!opt_silent)
+    fprintf(stdout, "rc: %d, mysql_stmt_errno: %d, mysql_errno: %d\n",
+            rc, mysql_stmt_errno(stmt), mysql_errno(mysql1));
+  DIE_UNLESS(rc && mysql_stmt_errno(stmt) && mysql_errno(mysql1));
+
+  /* Close connection to server */
+  mysql_close(mysql1);
+
+  /*
+    Use the same stmt and reprepare with another query that
+    suceeds. The prepare should fail with error 2013 since
+    connection to server has been closed.
+  */
+  rc= mysql_stmt_prepare(stmt, "SHOW STATUS", 12);
+  if (!opt_silent)
+    fprintf(stdout, "rc: %d, mysql_stmt_errno: %d\n",
+            rc, mysql_stmt_errno(stmt));
+  DIE_UNLESS(rc && mysql_stmt_errno(stmt));
+
+  mysql_stmt_close(stmt);
+  DIE_UNLESS(mysql_errno(mysql1));
+}
+
 
 static void test_view_sp_list_fields()
 {
@@ -15009,7 +15085,7 @@ static void test_bug17667()
     }
     else
     {
-      assert(0==1);
+      DIE_UNLESS(0==1);
     }
   }
 
@@ -15588,6 +15664,7 @@ static struct my_tests_st my_tests[]= {
   { "test_bug15752", test_bug15752 },
   { "test_bug21206", test_bug21206 },
   { "test_bug21726", test_bug21726 },
+  { "test_bug15518", test_bug15518 },
   { 0, 0 }
 };