Bug#102300: unison: unison does not detect changes if time stamp didn't change

[Mark J. Nelson <mjn@anadrome.org>]

(Triaging old bugs.)

The current version of the manual clarifies that this is intended
default behavior, though it can be changed through a preference:

"When running with the fastcheck preference set to true—the default on
Unix systems—Unison uses file modtimes for a quick first pass to tell
which files have definitely not changed; then, for each file that might
have changed, it computes a fingerprint of the file's contents and
compares it against the last-synchronized contents."

Users who have programs that routinely update files without updating the
modtime probably need to set fastcheck to false, which will avoid
accidentally missing such files, at the expense of slower
synchronization. I believe that's uncommon on Unix, which is the reason
for the default.

-- 
Mark J. Nelson
Anadrome Research
http://www.kmjn.org