LP #1730168: pt-online-schema-change is stuck when the table that is being altered is filtered out in the slave

**Reported in Launchpad by Jaime Sicam last update 05-01-2018 12:22:27

pt-online-schema-change --execute --alter="engine=innodb" --no-check-replication-filters h=127.0.0.1,P=20594,u=root,p=msandbox,D=employees,t=titles --skip-check-slave-lag=h=127.0.0.1,P=20595,u=root,p=msandbox
Found 2 slaves:
kits-desktop -> SBslave1:20595
kits-desktop -> SBslave2:20596
Will check slave lag on:
kits-desktop -> SBslave1:20595
kits-desktop -> SBslave2:20596
Operation, tries, wait:
analyze_table, 10, 1
copy_rows, 10, 0.25
create_triggers, 10, 1
drop_triggers, 10, 1
swap_tables, 10, 1
update_foreign_keys, 10, 1
Altering `employees`.`titles`...
Creating new table...
Created new table employees._titles_new OK.
Waiting forever for new table `employees`.`_titles_new` to replicate to kits-desktop...
Waiting for kits-desktop: 0% 00:00 remain
Waiting for kits-desktop: 0% 00:00 remain
Waiting for kits-desktop: 0% 00:00 remain
Waiting for kits-desktop: 0% 00:00 remain
Waiting for kits-desktop: 0% 00:00 remain
Waiting for kits-desktop: 0% 00:00 remain
Waiting for kits-desktop: 0% 00:00 remain
Waiting for kits-desktop: 0% 00:00 remain
Waiting for kits-desktop: 0% 00:00 remain

To reproduce, add a filter on the database of the slave's my.cnf config and restart:
replicate-wild-ignore-table=employees.%

Then try running pt-online-schema-change on a table of the filtered database on the master:
pt-online-schema-change --execute --alter="engine=innodb" --no-check-replication-filters h=127.0.0.1,P=20594,u=root,p=msandbox,D=employees,t=titles