Bug#24354 option "--extern" of mysql-test-run.pl does not work anymore

 - Better control of when to create/remove vardir


mysql-test/mysql-test-run.pl:
  Split the part the function cleanup_stale_files in two parts
    - one that removes any old var directories
    - one that setup var in te proper location
  
  If running against extern server and no vardir has been created in the specified
  location, run the latter function to create the vardir structure. Else print
  message saying the vardir already exists and continue.

mysql-test/mysql-test-run.pl

@@ -312,7 +312,8 @@ sub datadir_setup ();
 sub executable_setup ();
 sub environment_setup ();
 sub kill_running_servers ();
-sub cleanup_stale_files ();
+sub remove_stale_vardir ();
+sub setup_vardir ();
 sub check_ssl_support ($);
 sub check_running_as_root();
 sub check_ndbcluster_support ($);
@@ -1168,6 +1169,7 @@ sub command_line_setup () {
 
     # Setup master->[0] with the settings for the extern server
     $master->[0]->{'path_sock'}=  $opt_socket if $opt_socket;
+    mtr_report("Using extern server at '$master->[0]->{path_sock}'");
   }
   else
   {
@@ -1891,12 +1893,24 @@ sub kill_running_servers () {
    }
 }
 
-sub cleanup_stale_files () {
+sub created_by_mem_filename(){
+  return "$glob_mysql_test_dir/var/created_by_mem";
+}
+
 
-  my $created_by_mem_file= "$glob_mysql_test_dir/var/created_by_mem";
+#
+# Remove var and any directories in var/ created by previous
+# tests
+#
+sub remove_stale_vardir () {
 
   mtr_report("Removing Stale Files");
 
+  # Safety!
+  mtr_error("No, don't remove the vardir when running with --extern")
+    if $opt_extern;
+
+  mtr_verbose("opt_vardir: $opt_vardir");
   if ( $opt_vardir eq $default_vardir )
   {
     #
@@ -1905,29 +1919,37 @@ sub cleanup_stale_files () {
     if ( -l $opt_vardir)
     {
       # var is a symlink
-      if (-f $created_by_mem_file)
+      if (-f created_by_mem_filename() )
       {
 	# Remove the directory which the link points at
+	mtr_verbose("Removing " . readlink($opt_vardir));
 	rmtree(readlink($opt_vardir));
 	# Remove the entire "var" dir
+	mtr_verbose("Removing $opt_vardir/");
 	rmtree("$opt_vardir/");
 	# Remove the "var" symlink
+	mtr_verbose("unlink($opt_vardir)");
 	unlink($opt_vardir);
       }
       else
       {
 	# Some users creates a soft link in mysql-test/var to another area
-	# - allow it
+	# - allow it, but remove all files in it
+
 	mtr_report("WARNING: Using the 'mysql-test/var' symlink");
-	rmtree("$opt_vardir/log");
-	rmtree("$opt_vardir/ndbcluster-$opt_ndbcluster_port");
-	rmtree("$opt_vardir/run");
-	rmtree("$opt_vardir/tmp");
+
+	my $dir=       shift;
+	foreach my $bin ( glob("$opt_vardir/*") )
+	{
+	  mtr_verbose("Removing bin $bin");
+	  rmtree($bin);
+	}
       }
     }
     else
     {
       # Remove the entire "var" dir
+      mtr_verbose("Removing $opt_vardir/");
       rmtree("$opt_vardir/");
     }
   }
@@ -1939,21 +1961,33 @@ sub cleanup_stale_files () {
 
     # Remove the var/ dir in mysql-test dir if any
     # this could be an old symlink that shouldn't be there
+    mtr_verbose("Removing $default_vardir");
     rmtree($default_vardir);
 
     # Remove the "var" dir
+    mtr_verbose("Removing $opt_vardir/");
     rmtree("$opt_vardir/");
   }
+}
+
+#
+# Create var and the directories needed in var
+#
+sub setup_vardir() {
+  mtr_report("Creating Directories");
 
   if ( $opt_mem )
   {
     # Runinng with var as a link to some "memory" location, normally tmpfs
-    rmtree($opt_mem);
+    mtr_verbose("Creating $opt_mem");
     mkpath($opt_mem);
-    mtr_report("Creating symlink from $opt_vardir to $opt_mem");
+
+    mtr_report("Symlinking 'var' to '$opt_mem'");
     symlink($opt_mem, $opt_vardir);
+
     # Put a small file to recognize this dir was created by --mem
-    mtr_tofile($created_by_mem_file, $opt_mem);
+    mtr_verbose("Creating " . created_by_mem_filename());
+    mtr_tofile(created_by_mem_filename(), $opt_mem);
   }
 
   mkpath("$opt_vardir/log");
@@ -1961,10 +1995,9 @@ sub cleanup_stale_files () {
   mkpath("$opt_vardir/tmp");
   mkpath($opt_tmpdir) if $opt_tmpdir ne "$opt_vardir/tmp";
 
-  # Remove old and create new data dirs
+  # Create new data dirs
   foreach my $data_dir (@data_dir_lst)
   {
-    rmtree("$data_dir");
     mkpath("$data_dir/mysql");
     mkpath("$data_dir/test");
   }
@@ -2503,21 +2536,39 @@ sub initialize_servers () {
 
   datadir_setup();
 
-  if ( ! $opt_extern )
+  if ( $opt_extern )
+  {
+    # Running against an already started server, if the specified
+    # vardir does not already exist it should be created
+    if ( ! -d $opt_vardir )
+    {
+      mtr_report("Creating '$opt_vardir'");
+      setup_vardir();
+    }
+    else
+    {
+      mtr_report("No need to create '$opt_vardir' it already exists");
+    }
+  }
+  else
   {
     kill_running_servers();
 
     if ( ! $opt_start_dirty )
     {
-      cleanup_stale_files();
+      remove_stale_vardir();
+      setup_vardir();
+
       mysql_install_db();
       if ( $opt_force )
       {
+	# Save a snapshot of the freshly installed db
+	# to make it possible to restore to a known point in time
 	save_installed_db();
       }
     }
-    check_running_as_root();
   }
+  check_running_as_root();
 }
 
 sub mysql_install_db () {
@@ -4663,7 +4714,7 @@ Options that pass on options
 
 Options to run test on running server
 
-  extern                Use running server for tests FIXME DANGEROUS
+  extern                Use running server for tests
   ndb-connectstring=STR Use running cluster, and connect using STR
   ndb-connectstring-slave=STR Use running slave cluster, and connect using STR
   user=USER             User for connection to extern server