This error was generated while trying to add a new 'interest' tag to a user's profile. The tag was deliberately entered as a float (to see what would happen).

ERROR: invalid input syntax for integer: " 4.2"

SELECT name FROM mdl_tag WHERE id = ' 4.2'

    * line 684 of lib/dmllib.php: call to debugging()
    * line 481 of lib/dmllib.php: call to get_recordset_sql()
    * line 421 of lib/dmllib.php: call to get_record_sql()
    * line 179 of tag/lib.php: call to get_record()
    * line 323 of tag/lib.php: call to tag_name()
    * line 457 of tag/lib.php: call to tag_name_from_string()
    * line 58 of user/editlib.php: call to update_item_tags()
    * line 111 of user/edit.php: call to useredit_update_interests()

This error is trivial in as much as the tag is not stored, and clicking on the continue button is available and works.

I expect that it is not possible to have tag names that are integers or floats, because the use of $tag_names_or_ids_cvs (a tag named with a number will be mistaken for an id passed here).

May I suggest a bit of javascript on the input fields for any tag entry that would inform the user that they has entered an illegal tag name, or a help button that explains the situation.