Hello,
 Don't know if it's a bug or an evolution, but after migrating my xwiki to
 1.2.2, when I attach a new file to a page, all spaces characters are trimmed
 from the name. I didn't found anything about that in Jira.
 For example "My Doc Attached.doc" gets renamed to
"MyDocAttached.doc". 
http://jira.xwiki.org/jira/browse/XWIKI-2090
http://jira.xwiki.org/jira/browse/XWIKI-2087
The use of the clearName method for attachment names is a temporary
fix until the resolution of all our encoding issues.
  I see at least one issue coming from this : if you
attach the same file it's
 not considered the same because it's renamed. Your existing links also link
 to the previous version, and it's not easy to find by end-user.
 And anyway you don't want the file to be renamed when attached … 
Yes this is a drawback of this fix.
JV.