BUG#27448061: MYSQLD--DEFAULTS-FILE TEST FAILS FOR NDB RELEASES

              PREVIOUS TO MYSQL 8.0

Description :
-------------
The mysqld--defaults-file test fails when the test suite is run from a
non-canonical path, which happens when the current working directory
when mysql-test-run.pl is started contains a symbolic link.

The problem is that this test case uses --replace-result with
$MYSQL_TEST_DIR. This variable is a potentially non-canonical path
based on the current working directory when mtr is started. However,
the path in the expected error message from mysqld contains a
canonical path. This means it does not contain $MYSQL_TEST_DIR if
mtr's working directory is not the canonical path of the working
directory.

Because other tests produce output that may contain non-canonical
paths, making $MYSQL_TEST_DIR always canonical is not a fix.

Fix :
-----
Introduced a new environment variable '$ABS_MYSQL_TEST_DIR' which will
contin the canonical path to the test directory and replaced
$MYSQL_TEST_DIR with the new variable in main.mysqld--defaults-file
test file.

This is a back-port of BUG#24579973.

Change-Id: I3b8df6f2d7ce2b04e188a896d76250cc1addbbc1

mysql-test/mysql-test-run.pl

 #!/usr/bin/perl
 # -*- cperl -*-
 
-# Copyright (c) 2004, 2017, Oracle and/or its affiliates. All rights reserved.
+# Copyright (c) 2004, 2018, Oracle and/or its affiliates. All rights reserved.
 #
 # This program is free software; you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
@@ -2344,6 +2344,7 @@ sub environment_setup {
   $ENV{'DEFAULT_MASTER_PORT'}= $mysqld_variables{'port'};
   $ENV{'MYSQL_TMP_DIR'}=      $opt_tmpdir;
   $ENV{'MYSQLTEST_VARDIR'}=   $opt_vardir;
+  $ENV{'MYSQL_TEST_DIR_ABS'}= getcwd();
   $ENV{'MYSQL_BINDIR'}=       "$bindir";
   $ENV{'MYSQL_SHAREDIR'}=     $path_language;
   $ENV{'MYSQL_CHARSETSDIR'}=  $path_charsetsdir;

mysql-test/t/mysqld--defaults-file.test

@@ -13,19 +13,21 @@ exec $MYSQLD --defaults-file=/path/with/no/extension --print-defaults 2>&1;
 --error 1
 exec $MYSQLD --defaults-file=/path/with.ext --print-defaults 2>&1;
 
---replace_result $MYSQL_TEST_DIR MYSQL_TEST_DIR
+# Using $MYSQL_TEST_DIR_ABS which contains canonical path to the
+# test directory since --print-default prints the absolute path.
+--replace_result $MYSQL_TEST_DIR_ABS MYSQL_TEST_DIR
 --error 1
 exec $MYSQLD --defaults-file=relative/path/with.ext --print-defaults 2>&1;
 
---replace_result $MYSQL_TEST_DIR MYSQL_TEST_DIR
+--replace_result $MYSQL_TEST_DIR_ABS MYSQL_TEST_DIR
 --error 1
 exec $MYSQLD --defaults-file=relative/path/without/extension --print-defaults 2>&1;
 
---replace_result $MYSQL_TEST_DIR MYSQL_TEST_DIR
+--replace_result $MYSQL_TEST_DIR_ABS MYSQL_TEST_DIR
 --error 1
 exec $MYSQLD --defaults-file=with.ext --print-defaults 2>&1;
 
---replace_result $MYSQL_TEST_DIR MYSQL_TEST_DIR
+--replace_result $MYSQL_TEST_DIR_ABS MYSQL_TEST_DIR
 --error 1
 exec $MYSQLD --defaults-file=no_extension --print-defaults 2>&1;