Say a Windows user attaches a file called "5/4/06_test.txt" to an email, and sends it to JIRA (polling a POP/IMAP service) running on unix. JIRA creates an issue or comment with this attachment. However it prints a warning:

2006-07-07 11:31:23,038 WARN [jira.issue.managers.DefaultAttachmentManager] Creating attachment without a file.  Aborting

and in the attachments directory, one finds the file saved, but in an invalid/unusual format, with a subdirectory:

./10003_5/4/06_test.txt

The URL to the attachment will be something like:

http://localhost:8090/jira/secure/attachment/10003/5%2F4%2F06_test.txt

This URL works with Tomcat, but mod_proxy and mod_jk don't like it. One gets the error:

Not Found

The requested URL /jira/secure/attachment/10003/5/4/06_test.txt was not found on this server.
Apache/2.0.54 (Debian GNU/Linux) DAV/2 SVN/1.2.3 mod_python/3.1.3 Python/2.3.5 PHP/4.4.0-4 mod_perl/2.0.1 Perl/v5.8.7 Server at localhost Port 80

To fix this we need to check filenames for invalid characters ("/"), and if present, store the file on disk with the invalid characters stripped. Since the name the file is served as is stored in the database, it doesn't actually matter what the filename on the server is - it will be served to the user correctly.