Support multi-value column type modifiers for _mysql_data_types_cache

[jeroenpf]

Fixes: #122

This fix will skip over tokens until it finds the closing bracket of the type modifier ) instead of consuming exactly 3. This should account for data types that support more than one value as a modifier, such as: enum, float, decimal, double.

Additionally, I've added support for enums. There are plugins that use enum fields and it makes sense to convert those to text in SQLite.

Testing instructions

Confirm the tests pass

[katinthehatsite]

Thanks for adding the test - are there any other steps that I could manually run on my end to confirm that the issue is fixed?

[jeroenpf]

@katinthehatsite

The unit tests should cover this change but if you want to do it manually you could try:

Create a site in Studio, replace the sqlite database integration plugin with a clone of this repo and branch and then install a plugin that uses enum and/or decimal fields. The woocommerce plugin will add tables with decimals and the redirection plugin will create tables with enums.

After you installed those plugins, you can inspect the _mysql_data_types_cache table and ensure that the columns that have decimal or enum types are properly represented in that table.

After that you can try and run a query using $wpdb->query('SHOW CREATE table);` and see if it outputs a valid MySQL-compatible create statement.

[bgrgicak]

Thanks @jeroenpf! The PR looks good.