Convert "blocks" table to utf8mb4 to accept 4 byte utf8 characters

[joshlory]

Also changed the "category" column from t.text -> t.string. Category should be a short string.

After migration:

mysql> show full columns from blocks;
+-------------+--------------+--------------------+------+-----+---------+----------------+---------------------------------+---------+
| Field       | Type         | Collation          | Null | Key | Default | Extra          | Privileges                      | Comment |
+-------------+--------------+--------------------+------+-----+---------+----------------+---------------------------------+---------+
| id          | int(11)      | NULL               | NO   | PRI | NULL    | auto_increment | select,insert,update,references |         |
| name        | varchar(255) | utf8mb4_unicode_ci | YES  |     | NULL    |                | select,insert,update,references |         |
| level_type  | varchar(255) | utf8mb4_unicode_ci | YES  |     | NULL    |                | select,insert,update,references |         |
| category    | varchar(255) | utf8mb4_unicode_ci | YES  |     | NULL    |                | select,insert,update,references |         |
| config      | text         | utf8mb4_unicode_ci | YES  |     | NULL    |                | select,insert,update,references |         |
| helper_code | text         | utf8mb4_unicode_ci | YES  |     | NULL    |                | select,insert,update,references |         |
| created_at  | datetime     | NULL               | NO   |     | NULL    |                | select,insert,update,references |         |
| updated_at  | datetime     | NULL               | NO   |     | NULL    |                | select,insert,update,references |         |
+-------------+--------------+--------------------+------+-----+---------+----------------+---------------------------------+---------+
8 rows in set (0.00 sec)

[joshlory]

Rails annotates the model as text(65355) but MySQL wants the value to be the actual number of characters stored. 65355 / 3 = 21845.

[joshlory]

Trying to add emoji to a block definition shouldn't break the deploy pipeline

[joshlory]

Intentional change. Category should be a short string.

[balderdash]

🐼!

[wjordan]

Migration looks good. I thought handling utf8mb4 queries would also require changes to our mysql2 adapter's client-connection charset/encoding settings as well. This migration should be safe either way, but might not be effective without further changes to the client. In any case, it would be good to test/verify that this migration actually fixes emoji input in block definitions as expected.

[joshlory]

@wjordan good call, I updated the default adaptor to also support utf8mb4 in commit 2ba71c4. Are there any downsides to this change?

When testing locally, tables that have utf8 encoding instead of utf8mb4 still get the Mysql2::Error: Incorrect string value error when trying to save 4-byte emoji, but saving these the "blocks" table now works.

[wjordan]

LGTM. I don't know any other details on whether the client-adapter encoding change poses other potential problems, but as long as the test suite passes (which it looks like it did), I wouldn't expect there to be any issues.