Obsolete:Diff hell
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We've had these intermittently for ages, but reporting has gone way up the last few days. Diffs with mysteriously repeating lines, like this:
To help track it down, I added some debug comments, then did a batch test hitting and re-hitting a bad diff that was reported in IRC...
Testing
Did 1000 purge hits to this diff.
8 of these hits gave the bogus, extra-long renderings:
diff-144:<!-- diff generator: wikidiff2 srv141 2008-04-25 23:13:49 --> diff-149:<!-- diff generator: wikidiff2 srv99 2008-04-25 23:13:52 --> diff-214:<!-- diff generator: wikidiff2 srv98 2008-04-25 23:14:38 --> diff-326:<!-- diff generator: wikidiff2 srv129 2008-04-25 23:15:57 --> diff-484:<!-- diff generator: wikidiff2 srv132 2008-04-25 23:17:50 --> diff-755:<!-- diff generator: wikidiff2 srv88 2008-04-25 23:20:59 --> diff-774:<!-- diff generator: wikidiff2 srv119 2008-04-25 23:21:13 --> diff-946:<!-- diff generator: wikidiff2 srv83 2008-04-25 23:23:12 -->
Spot checks confirm that the same server will render perfectly correct ones as well:
$ ls -l `grep -l srv83 diff*` -rw-r--r-- 1 brion staff 20833 Apr 25 16:14 diff-224 -rw-r--r-- 1 brion staff 20833 Apr 25 16:19 diff-609 -rw-r--r-- 1 brion staff 20833 Apr 25 16:20 diff-723 -rw-r--r-- 1 brion staff 20833 Apr 25 16:21 diff-792 -rw-r--r-- 1 brion staff 20833 Apr 25 16:23 diff-936 -rw-r--r-- 1 brion staff 23284 Apr 25 16:23 diff-946
Notes:
- The exact number of repeated lines was variable mostly 5x, some 2x
- all bad hits were Fedora machines (8 of 515 hits; the other 485 were to Ubuntu machines srv150-189)
- all hits reported wikidiff2
- a further test running the diff directly in a command-line script on srv83 25,000 times in one process had encountered no failures.