When uploading a file with a filename that already exist, nothing happens (no error message nor is the file updated)
In Document Library Portlet..
1) Upload a file called "test.txt" with contents "testing 1.2.3"
2) Upload a different file called "test.txt" with different contents.. "test.. 4.5.6" (using the java upload tool)
3) There will be a "All uploads complete" message, but if you look at the existing "test.txt" file.. it has not been updated.. nor has any new file been added.. nor is there an error message displayed to the user to indicate that there was an error.