mrkgnao: What MaGog does is get the file information on every single file. If two files have exactly the same file name AND exactly the same modification time (down to the second) AND exactly the same size, MaGog considers them the same and reports them once.
This logic is used both to identify identical extras and to identify multilingual installers (i.e. the same installer listed under several languages).
ATimson: That makes perfect sense. Thanks!
Oops. Sorry. My mistake.
What I described above was the original algorithm.
However, because GOG blocks my IP if I access my library too many times in a given period of time and because the original algorithm required two accesses for each file (one to get the file name and one to get the date/time and size), I changed the algorithm in order to reduce the number of acceses, so that it now compares only file names (i.e. two accesses for the first copy, one access for each duplicate), not all three parameters.
At the time of the change, the two algorithms yielded the same results (i.e. GOG did not have two files that had the same name but differed in date/time or size), but it is theoretically possible such a thing may occur and MaGog will miss it (although I expect at some point some human will notice the bug and draw my attention to it).
It's a compromise, but with the limitations GOG imposes on me, I felt it necessary. I will restore the original algorithm when GOG whitelists MaGog's IP or when hell freezes over, whichever comes first. Or when someone identifies a pair of identically-named, yet different, files.
Sorry for the confusion. My memory isn't what it used to be (if I correctly remember what it used to be).
