DatabaseSchema_mysql::fieldExists() does not escape the column name

Thanks for reporting and working on this.

These methods (tableExists() and fieldExists()) were removed from MySQL module Schema class in D10 some time ago, see: #2797141: Remove the methods tableExists() and fieldExists() from Drupal\Core\Database\Driver\mysql\Schema → .

It is true that D7 still claims that it supports MySQL 5.0.15+ (see: https://www.drupal.org/docs/7/system-requirements/database-server → ), but we should consider also a second option - to follow D10 and drop these MySQL specific methods, as I doubt that there is significant amount of up-to-date sites using MySQL < 5.0.77 (where it should be already fixed #2797141-24: Remove the methods tableExists() and fieldExists() from Drupal\Core\Database\Driver\mysql\Schema → ). Just for info, MySQL 5.0 was EOL on January 9, 2012.

We will discuss which approach will be better.

I have created a second MR (!5229) with alternative approach mentioned in #3 (removing the methods). Seems like the test are green after this change.