Fix for Bug#56817 - mysqlhotcopy tests fail when DBI and DBD-mysql perl modules are not found

Third updated patch - this version also includes copyright notice in added Perl script.
This patch implements a check for such modules at runtime. If modules are not found or unable to load, the test is skipped with 
the following message:
            
            [ skipped ]  Test needs Perl modules DBI and DBD::mysql
            
Checks are done via a helper Perl script which looks for the module in a runtime environment that is as similar to that of the 
mysqlhotcopy script as possible (thus not intended for Windows environments at this time).
The helper script tells mysql-test about the result by writing information to a temporary file that is later read by mysql-test.
See comments in added files (have_dbi_dbd-mysql.inc and checkDBI_DBD-mysql.pl) for details.
The patch also removes the mysqlhotcopy tests from the list of disabled tests.

1 files changed, 97 insertions, 0 deletions

diff --git a/mysql-test/std_data/checkDBI_DBD-mysql.pl b/mysql-test/std_data/checkDBI_DBD-mysql.pl
new file mode 100644
index 00000000000..f001e471081
--- /dev/null
+++ b/mysql-test/std_data/checkDBI_DBD-mysql.pl
@@ -0,0 +1,97 @@
+#!/usr/bin/perl
+
+# Copyright (c) 2011, 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 Library General Public
+# License as published by the Free Software Foundation; version 2
+# of the License.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+# Library General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+
+
+################################################################################
+#
+# This perl script checks for availability of the Perl modules DBI and
+# DBD::mysql using the "current" perl interpreter.
+#
+# Useful for test environment checking before testing executable perl scripts
+# in the MySQL Server distribution.
+#
+# NOTE: The "shebang" on the first line of this script should always point to
+#       /usr/bin/perl, so that we can use this script to check whether or not we
+#       support running perl scripts with such a shebang without specifying the
+#       perl interpreter on the command line. Such a script is mysqlhotcopy.
+#
+#       When run as "checkDBI_DBD-mysql.pl" the shebang line will be evaluated
+#       and used. When run as "perl checkDBI_DBD-mysql.pl" the shebang line is
+#       not used.
+#
+# NOTE: This script will create a temporary file in MTR's tmp dir.
+#       If modules are found, a mysql-test statement which sets a special
+#       variable is written to this file. If one of the modules is not found
+#       (or cannot be loaded), the file will remain empty.
+#       A test (or include file) which sources that file can then easily do
+#       an if-check on the special variable to determine success or failure.
+#
+#       Example:
+#
+#         --let $perlChecker= $MYSQLTEST_VARDIR/std_data/checkDBI_DBD-mysql.pl
+#         --let $resultFile= $MYSQL_TMP_DIR/dbidbd-mysql.txt
+#         --chmod 0755 $perlChecker
+#         --exec $perlChecker
+#         --source $resultFile
+#         if (!$dbidbd) {
+#             --skip Test needs Perl modules DBI and DBD::mysql
+#         } 
+#
+#       The calling script is also responsible for cleaning up after use:
+#
+#         --remove_file $resultFile
+#
+# Windows notes: 
+#   - shebangs may work differently - call this script with "perl " in front.
+#
+# See mysql-test/include/have_dbi_dbd-mysql.inc for example use of this script.
+# This script should be executable for the user running MTR.
+#
+################################################################################
+
+BEGIN {
+    # By using eval inside BEGIN we can suppress warnings and continue after.
+    # We need to catch "Can't locate" as well as "Can't load" errors.
+    eval{
+        $FOUND_DBI=0;
+        $FOUND_DBD_MYSQL=0;
+
+        # Check for DBI module:
+        $FOUND_DBI=1 if require DBI;
+
+        # Check for DBD::mysql module
+        $FOUND_DBD_MYSQL=1 if require DBD::mysql;
+    };
+};
+
+# Open a file to be used for transfer of result back to mysql-test.
+# The file must be created whether we write to it or not, otherwise mysql-test 
+# will complain if trying to source it. 
+# An empty file indicates failure to load modules.
+open(FILE, ">", $ENV{'MYSQL_TMP_DIR'}.'/dbidbd-mysql.txt');
+
+if ($FOUND_DBI && $FOUND_DBD_MYSQL) {
+    # write a mysql-test command setting a variable to indicate success
+    print(FILE 'let $dbidbd= FOUND_DBI_DBD-MYSQL;'."\n");
+}
+
+# close the file.
+close(FILE);
+
+1;
+