initenv with non-utf8 mysql database should give a more helpful error

[Ethan Jucovy <ethan.jucovy@…>]

If I create a MySQL database for a new Trac environment but forget to create the database with the UTF8 character set, then trac-admin /path/to/env initenv projectname mysql://connectionstring fails with a mysterious error:

Creating and Initializing Project
Initenv for '/path/to/env' failed. 
Failed to create environment.
unsupported operand type(s) for /: 'int' and 'NoneType'
Traceback (most recent call last):
  File "trac/trac/admin/console.py", line 455, in do_initenv
    options=options)
  File "trac/trac/core.py", line 124, in __call__
    self.__init__(*args, **kwargs)
  File "trac/trac/env.py", line 281, in __init__
    self.create(options)
  File "trac/trac/env.py", line 584, in create
    DatabaseManager(self).init_db()
  File "trac/trac/db/api.py", line 249, in init_db
    connector.init_db(**args)
  File "trac/trac/db/mysql_backend.py", line 119, in init_db
    for stmt in self.to_sql(table, utf8_size=utf8_size):
  File "trac/trac/db/mysql_backend.py", line 168, in to_sql
    utf8_size=utf8_size))
  File "trac/trac/db/mysql_backend.py", line 132, in _collist
    limit_col = 767 / utf8_size
TypeError: unsupported operand type(s) for /: 'int' and 'NoneType'

This is not a very Google-friendly error. It would be nice if Trac could detect the problem before this TypeError occurs, and raise an error message that explains what the user did wrong.

[Ethan Jucovy <ethan.jucovy@…>]

patch to raise a more user-friendly error if mysql db is not using utf8 charset

[Christian Boos]

Good idea!

However, no need to put the link in full in the error message.

Try something like:

mysql_utf8 = tag.a(_("How to set up MySQL correctly...", 
                   href='http://trac.edgewall.org/wiki/...')
tag_("... See %(mysql_utf8)s ...", mysql_utf8=mysql_utf8)

(see e.g. source:tags/trac-0.12/trac/versioncontrol/web_ui/util.py@:64-71#L64​)

[Jun Omae]

Related to comment:16:ticket:8089 and T8089 MySQL charset collation check on create DB.patch.

I think the message of TracError should be plain text. Because initenv command normally is executed from user's terminal.

[Jun Omae]

After [12148], Trac verifies the charset and collation. See #10993.

Trac [/var/trac/1.0-test]> initenv title mysql://tracuser:password@localhost/trac
Creating and Initializing Project
Initenv for '/var/trac/1.0-test' failed.
Failed to create environment.
The charset and collation of database are 'latin1' and 'latin1_swedish_ci'. The database must be created with one of (('utf8', 'utf8_bin'), ('utf8mb4', 'utf8mb4_bin')).
Traceback (most recent call last):
  File "trac/admin/console.py", line 456, in do_initenv
    options=options)
...