Changes as requested by daniel in merge feedback:

- change to get_slave_lag
- if then else
- chop comments 80 char wide

bin/pt-online-schema-change

@@ -8105,25 +8105,27 @@ sub main {
          return;
       };
 
-      my $get_lag = sub {
+      my $get_lag;
-         my ($cxn) = @_;
+      # The plugin is able to override the slavelag check so tools like 
-         my $dbh = $cxn->dbh();
+      # pt-heartbeat or other replicators (Tungsten...) can be used to 
-         if ( !$dbh || !$dbh->ping() ) {
+      # measure replication lag
-            eval { $dbh = $cxn->connect() };  # connect or die trying
+      if ( $plugin && $plugin->can('get_slave_lag') ) {
-            if ( $EVAL_ERROR ) {
+         $get_lag = $plugin->get_slave_lag(oktorun => \$oktorun);
-               $oktorun = 0;  # flag for cleanup tasks
+      } else {      
-               chomp $EVAL_ERROR;
+         $get_lag = sub {
-               die "Lost connection to replica " . $cxn->name()
+            my ($cxn) = @_;
-                  . " while attempting to get its lag ($EVAL_ERROR)\n";
+            my $dbh = $cxn->dbh();
+            if ( !$dbh || !$dbh->ping() ) {
+               eval { $dbh = $cxn->connect() };  # connect or die trying
+               if ( $EVAL_ERROR ) {
+                  $oktorun = 0;  # flag for cleanup tasks
+                  chomp $EVAL_ERROR;
+                  die "Lost connection to replica " . $cxn->name()
+                     . " while attempting to get its lag ($EVAL_ERROR)\n";
+               }
             }
-         }
+            return $ms->get_slave_lag($dbh);
-         return $ms->get_slave_lag($dbh);
+         };
-      };
-
-      # The plugin is able to override the slavelag check so tools like pt-heartbeat
-      # or other replicators (Tungsten...) can be used to measure replication lag
-      if ( $plugin && $plugin->can('override_slavelag_check') ) {
-         $get_lag = $plugin->override_slavelag_check(oktorun => \$oktorun);
       }
       
       $replica_lag = new ReplicaLagWaiter(
@@ -11351,7 +11353,7 @@ These hooks, in this order, are called if defined:
    after_drop_old_table
    before_drop_triggers
    before_exit
-   override_slavelag_check
+   get_slave_lag
 
 Each hook is passed different arguments.  To see which arguments are passed
 to a hook, search for the hook's name in the tool's source code, like:

bin/pt-table-checksum

@@ -9579,27 +9579,29 @@ sub main {
          return;
       };
 
-      my $get_lag = sub {
+      my $get_lag;
-         my ($cxn) = @_;
+      # The plugin is able to override the slavelag check so tools like 
-         my $dbh = $cxn->dbh();
+      # pt-heartbeat or other replicators (Tungsten...) can be used to 
-         if ( !$dbh || !$dbh->ping() ) {
+      # measure replication lag
-            PTDEBUG && _d('Lost connection to slave', $cxn->name(),
+      if ( $plugin && $plugin->can('get_slave_lag') ) {
-               'while waiting for slave lag');
+         $get_lag = $plugin->get_slave_lag(oktorun => \$oktorun);
-            eval { $dbh = $cxn->connect() };  # connect or die trying
+      } else {
-            if ( $EVAL_ERROR ) {
+         $get_lag = sub {
-               $oktorun = 0;  # Fatal error
+            my ($cxn) = @_;
-               chomp $EVAL_ERROR;
+            my $dbh = $cxn->dbh();
-               die "Lost connection to replica " . $cxn->name()
+            if ( !$dbh || !$dbh->ping() ) {
-                  . " while attempting to get its lag ($EVAL_ERROR)";
+               PTDEBUG && _d('Lost connection to slave', $cxn->name(),
+                  'while waiting for slave lag');
+               eval { $dbh = $cxn->connect() };  # connect or die trying
+               if ( $EVAL_ERROR ) {
+                  $oktorun = 0;  # Fatal error
+                  chomp $EVAL_ERROR;
+                  die "Lost connection to replica " . $cxn->name()
+                     . " while attempting to get its lag ($EVAL_ERROR)";
+               }
             }
-         }
+            return $ms->get_slave_lag($dbh);
-         return $ms->get_slave_lag($dbh);
+         };
-      };
-
-      # The plugin is able to override the slavelag check so tools like pt-heartbeat
-      # or other replicators (Tungsten...) can be used to measure replication lag
-      if ( $plugin && $plugin->can('override_slavelag_check') ) {
-         $get_lag = $plugin->override_slavelag_check(oktorun => \$oktorun);
       }
       
       $replica_lag = new ReplicaLagWaiter(
@@ -12492,7 +12494,7 @@ These hooks, in this order, are called if defined:
    init
    before_replicate_check
    after_replicate_check
-   override_slavelag_check
+   get_slave_lag
    before_checksum_table
    after_checksum_table
 

t/pt-online-schema-change/plugin.t

@@ -56,7 +56,7 @@ my @called = $output =~ m/^PLUGIN \S+$/gm;
 is_deeply(
    \@called,
    [
-      'PLUGIN override_slavelag_check',
+      'PLUGIN get_slave_lag',
       'PLUGIN init',
       'PLUGIN before_create_new_table',
       'PLUGIN after_create_new_table',

t/pt-online-schema-change/samples/plugins/all_hooks.pm

@@ -96,9 +96,9 @@ sub before_exit {
    print "PLUGIN before_exit\n";
 }
 
-sub override_slavelag_check {
+sub get_slave_lag {
    my ($self, %args) = @_;
-   print "PLUGIN override_slavelag_check\n";
+   print "PLUGIN get_slave_lag\n";
 
    return sub { return 0; };
 }

t/pt-table-checksum/plugin.t

@@ -59,7 +59,7 @@ my @called = $output =~ m/^PLUGIN \S+$/gm;
 is_deeply(
    \@called,
    [
-      'PLUGIN override_slavelag_check',
+      'PLUGIN get_slave_lag',
       'PLUGIN init',
       'PLUGIN before_checksum_table',
       'PLUGIN after_checksum_table',

t/pt-table-checksum/samples/plugins/all_hooks.pm

@@ -26,9 +26,9 @@ sub after_replicate_check {
    print "PLUGIN after_replicate_check\n";
 }
  
-sub override_slavelag_check {
+sub get_slave_lag {
    my ($self, %args) = @_;
-   print "PLUGIN override_slavelag_check\n";
+   print "PLUGIN get_slave_lag\n";
    return sub { return 0; };
 }