[debian-mysql] Bug#799790: mysql-server-5.6: warns "No directory, logging in with HOME=/" on daemon start

[Julian Gilbey]

Package: mysql-server-5.6
Version: 5.6.25-4
Severity: normal

Though there is a HOME=/etc/mysql/ line in /etc/init.d/mysql, running
/etc/init.d/mysql start still warns: "No directory, logging in with
HOME=/".  I presume this is because the invocation

            # Start MySQL!
            su - mysql -s /bin/sh -c "/usr/bin/mysqld_safe > /dev/null 2>&1 &"
                        
Then if /etc/login.defs has DEFAULT_HOME set to no (the default),
mysql will fail to start.

A plausible solution is to remove the "-" from the invocation, so that
the environment is not reset, and the exported setting of HOME is
preserved.

   Julian

-- System Information:
Debian Release: stretch/sid
  APT prefers testing
  APT policy: (500, 'testing'), (500, 'stable')
Architecture: amd64 (x86_64)
Foreign Architectures: i386

Kernel: Linux 4.1.0-1-amd64 (SMP w/4 CPU cores)
Locale: LANG=en_GB.UTF-8, LC_CTYPE=en_GB.UTF-8 (charmap=UTF-8) (ignored: LC_ALL set to en_GB.UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: sysvinit (via /sbin/init)

Versions of packages mysql-server-5.6 depends on:
ii  adduser                3.113+nmu3
ii  debconf [debconf-2.0]  1.5.57
ii  init-system-helpers    1.23
ii  initscripts            2.88dsf-59.2
ii  libaio1                0.3.110-1
ii  libc6                  2.19-20
ii  libdbi-perl            1.633-1
ii  libgcc1                1:5.2.1-17
ii  libstdc++6             5.2.1-17
ii  libwrap0               7.6.q-25
ii  lsb-base               9.20150826
ii  mysql-client-5.6       5.6.25-4
ii  mysql-common           5.6.25-4
ii  mysql-server-core-5.6  5.6.25-4
ii  passwd                 1:4.2-3
ii  perl                   5.20.2-6
ii  psmisc                 22.21-2.1
ii  zlib1g                 1:1.2.8.dfsg-2+b1

Versions of packages mysql-server-5.6 recommends:
ii  libhtml-template-perl  2.95-2

Versions of packages mysql-server-5.6 suggests:
ii  bsd-mailx [mailx]  8.1.2-0.20150408cvs-1
pn  tinyca             <none>

-- debconf information:
  mysql-server/no_upgrade_when_using_ndb:
  mysql-server-5.6/postrm_remove_databases: false
  mysql-server/error_setting_password:
  mysql-server/password_mismatch:
  mysql-server-5.6/really_downgrade: false
  mysql-server-5.6/start_on_boot: true
  mysql-server-5.6/nis_warning: