Creating a Review Request for a source file with a long file path results 
in error.

What's the URL of the page containing the problem?
JSON API for creating a new reviewrequest.
https://reviewboard/api/json/reviewrequests/2016/diff/new/

What steps will reproduce the problem?
1. Edit or Add a source file with a really long path:
$> p4 add foo.test
//depot/project/foo/foo/foo/foo/foo/foo/foo/foo/foo/foo/this_is_one_really_
long_directory_in_which_im_using_to_try_and_reproduce_a_reviewboard_memcach
e_bug/foo/foo/foo/foo/foo/foo/foo/foo/foo/foo/foo/this_is_one_really_long_d
irectory_in_which_im_using_to_try_and_reproduce_a_reviewboard_memcache_bug/
foo/foo/foo/foo/foo.test#1 - opened for add

2. Now submit the file to reviewboard using JSON api (ie post-review or 
whatever tool you are using.)

You get this error:

Error: server request failed...
        uri=https://reviewboard/api/json/reviewrequests/2016/diff/new/
        stat=fail
        code=105
        msg=One or more fields had errors
Full server response:
{
  "fields" : {
    "path" : [
      "Data truncated for column 'source_file' at row 1"
    ]
  },
  "err" : {
    "msg" : "One or more fields had errors",
    "code" : 105
  },
  "stat" : "fail"
}



What is the expected output? What do you see instead?
ReviewBoard should be able to handle cases with really long paths. I do 
not know what the exact limit is, but we are reaching it. 

I found this problem trying to repro another issue with the memcache 
throwing and error that the cache key is too big (> 250 in length). i 
suspect that too is related to either the path or filename being too long 
for reviewboard/django/memcache to handle (I will post that bug once i 
track down further.)  

What operating system are you using? What browser?
CentOS 5.2

Please provide any additional information below.