BUG#23383: mysql_affected_rows() returns different values than

mysql_stmt_affected_rows()

The problem was that affected_rows for prepared statement wasn't updated
in the client library on the error.  The solution is to always update
affected_rows, which will be equal to -1 on the error.


libmysql/libmysql.c:
  Update status variables even in the case of an error.  Some variables
  have a defined value on the error (like affected_rows is -1), others are
  undefined, so updating them won't harm.
libmysqld/lib_sql.cc:
  Update status variables even in the case of an error.  Some variables
  have a defined value on the error (like affected_rows is -1), others are
  undefined, so updating them won't harm.
tests/mysql_client_test.c:
  Add test for bug#23383: mysql_affected_rows() returns different values
  than mysql_stmt_affected_rows().

libmysql/libmysql.c

@@ -2496,6 +2496,8 @@ static my_bool execute(MYSQL_STMT *stmt, char *packet, ulong length)
   NET	*net= &mysql->net;
   char buff[4 /* size of stmt id */ +
             5 /* execution flags */];
+  my_bool res;
+
   DBUG_ENTER("execute");
   DBUG_PRINT("enter",("packet: %s, length :%d",packet ? packet :" ", length));
 
@@ -2503,15 +2505,17 @@ static my_bool execute(MYSQL_STMT *stmt, char *packet, ulong length)
   int4store(buff, stmt->stmt_id);		/* Send stmt id to server */
   buff[4]= (char) 0;                            /* no flags */
   int4store(buff+5, 1);                         /* iteration count */
-  if (cli_advanced_command(mysql, COM_EXECUTE, buff, sizeof(buff),
-                           packet, length, 1, NULL) ||
-      (*mysql->methods->read_query_result)(mysql))
+
+  res= test(cli_advanced_command(mysql, COM_EXECUTE, buff, sizeof(buff),
+                                 packet, length, 1, NULL) ||
+            (*mysql->methods->read_query_result)(mysql));
+  stmt->affected_rows= mysql->affected_rows;
+  stmt->insert_id= mysql->insert_id;
+  if (res)
   {
     set_stmt_errmsg(stmt, net->last_error, net->last_errno, net->sqlstate);
     DBUG_RETURN(1);
   }
-  stmt->affected_rows= mysql->affected_rows;
-  stmt->insert_id= mysql->insert_id;
   DBUG_RETURN(0);
 }
 

libmysqld/lib_sql.cc

@@ -224,20 +224,24 @@ static int emb_stmt_execute(MYSQL_STMT *stmt)
 {
   DBUG_ENTER("emb_stmt_execute");
   char header[4];
+  my_bool res;
+
   int4store(header, stmt->stmt_id);
   THD *thd= (THD*)stmt->mysql->thd;
   thd->client_param_count= stmt->param_count;
   thd->client_params= stmt->params;
-  if (emb_advanced_command(stmt->mysql, COM_EXECUTE,0,0,
-                           header, sizeof(header), 1, stmt) ||
-      emb_mysql_read_query_result(stmt->mysql))
+
+  res= test(emb_advanced_command(stmt->mysql, COM_EXECUTE,0,0,
+                                 header, sizeof(header), 1, stmt) ||
+            emb_mysql_read_query_result(stmt->mysql));
+  stmt->affected_rows= stmt->mysql->affected_rows;
+  stmt->insert_id= stmt->mysql->insert_id;
+  if (res)
   {
     NET *net= &stmt->mysql->net;
     set_stmt_errmsg(stmt, net->last_error, net->last_errno, net->sqlstate);
     DBUG_RETURN(1);
   }
-  stmt->affected_rows= stmt->mysql->affected_rows;
-  stmt->insert_id= stmt->mysql->insert_id;
   DBUG_RETURN(0);
 }
 

tests/mysql_client_test.c

@@ -11949,6 +11949,83 @@ static void test_bug21726()
 }
 
 
+/*
+  BUG#23383: mysql_affected_rows() returns different values than
+  mysql_stmt_affected_rows()
+
+  Test that both mysql_affected_rows() and mysql_stmt_affected_rows()
+  return -1 on error, 0 when no rows were affected, and (positive) row
+  count when some rows were affected.
+*/
+static void test_bug23383()
+{
+  const char *insert_query= "INSERT INTO t1 VALUES (1), (2)";
+  const char *update_query= "UPDATE t1 SET i= 4 WHERE i = 3";
+  MYSQL_STMT *stmt;
+  my_ulonglong row_count;
+  int rc;
+
+  DBUG_ENTER("test_bug23383");
+  myheader("test_bug23383");
+
+  rc= mysql_query(mysql, "DROP TABLE IF EXISTS t1");
+  myquery(rc);
+
+  rc= mysql_query(mysql, "CREATE TABLE t1 (i INT UNIQUE)");
+  myquery(rc);
+
+  rc= mysql_query(mysql, insert_query);
+  myquery(rc);
+  row_count= mysql_affected_rows(mysql);
+  DIE_UNLESS(row_count == 2);
+
+  rc= mysql_query(mysql, insert_query);
+  DIE_UNLESS(rc != 0);
+  row_count= mysql_affected_rows(mysql);
+  DIE_UNLESS(row_count == (my_ulonglong)-1);
+
+  rc= mysql_query(mysql, update_query);
+  myquery(rc);
+  row_count= mysql_affected_rows(mysql);
+  DIE_UNLESS(row_count == 0);
+
+  rc= mysql_query(mysql, "DELETE FROM t1");
+  myquery(rc);
+
+  stmt= mysql_stmt_init(mysql);
+  DIE_UNLESS(stmt != 0);
+
+  rc= mysql_stmt_prepare(stmt, insert_query, strlen(insert_query));
+  check_execute(stmt, rc);
+
+  rc= mysql_stmt_execute(stmt);
+  check_execute(stmt, rc);
+  row_count= mysql_stmt_affected_rows(stmt);
+  DIE_UNLESS(row_count == 2);
+
+  rc= mysql_stmt_execute(stmt);
+  DIE_UNLESS(rc != 0);
+  row_count= mysql_stmt_affected_rows(stmt);
+  DIE_UNLESS(row_count == (my_ulonglong)-1);
+
+  rc= mysql_stmt_prepare(stmt, update_query, strlen(update_query));
+  check_execute(stmt, rc);
+
+  rc= mysql_stmt_execute(stmt);
+  check_execute(stmt, rc);
+  row_count= mysql_stmt_affected_rows(stmt);
+  DIE_UNLESS(row_count == 0);
+
+  rc= mysql_stmt_close(stmt);
+  check_execute(stmt, rc);
+
+  rc= mysql_query(mysql, "DROP TABLE t1");
+  myquery(rc);
+
+  DBUG_VOID_RETURN;
+}
+
+
 /*
   Read and parse arguments and MySQL options from my.cnf
 */
@@ -12176,6 +12253,7 @@ static struct my_tests_st my_tests[]= {
   { "test_bug15613", test_bug15613 },
   { "test_bug20152", test_bug20152 },
   { "test_bug21726", test_bug21726 },
+  { "test_bug23383", test_bug23383 },
   { 0, 0 }
 };