Core does not restrict the maximum size of extension-names (names of themes and modules) in any way; though it is actually (with inconsistent numbers) restricted in various database tables of core modules.
Restrict the number of characters extension-names can have.
[✓] Write a patch that restricts the module/theme size by throwing an exception; also add a testcase for this
[✓] Change the table columns containing the module/theme names and add upgrade paths for the existing tables
[✓] Add an upgrade path test
[✓] Document possible issues during the upgrade of an existing site and how to resolve them (Change record) See #115
[✓] Add a link to the documentation page when checking the upgrade requirements to this patch See #116
[✓] Add a validation handler for throwing a form error when a theme or module with a too long name is tried to be enabled
[✓] core gates docs minimal requirements review
[✓] Manual testing. See #124-129
[✓] Add test that will fail for enabling module with too long name in the UI. See #139.
[✓] Review the most current patch; If everything is fine: RTBC!
User interface changes
Extensions (themes and modules) won't be able to use shortnames longer than 50 characters.
There are no such long names in (contrib) modules/themes known on drupal.org, though this might be an issue for custom modules, such as features.
Original report by chx
I think 64 is enough. Anyone ever saw a longer one?
drupal.org record is http://drupal.org/project/db_export_edit_mysql_row_as_text_and_import at 43 characters.
PASSED: [[SimpleTest]]: [MySQL] 57,670 pass(es).
FAILED: [[SimpleTest]]: [MySQL] 57,855 pass(es), 1 fail(s), and 0 exception(s).
FAILED: [[SimpleTest]]: [MySQL] 57,707 pass(es), 1 fail(s), and 0 exception(s).