Here's the use case: I have a commercial software package that installs a large library (50+ GB, many thousands of files). I use this package on two machines: a desktop and a laptop. I would like to verify from time to time that the library installations match each other, so that when I move a project from one machine to the other it will behave in exactly the same way on both machines.
Right now I can't do that with SyncToy. The reason is that I must install library updates on each machine separately, because doing so updates other parts of the software outside the library. There is no way to install these updates at exactly the same time. As a result, the libraries on the two machines wind up with files that are identical but have different update times.
If I run SyncToy with such files, it decides that it can't figure out what to do with them, so it copies the files both ways and puts a ".1" suffix in one of the copies. The result is to duplicate many files in my library.
The best solution I've been able to figure out for this problem so far would be a new option in SyncToy that might be called "Consolidate identical files with different dates." The idea would be:
1) If two files have different lengths, they are different. This is an easy determination to make. 2) If two files have the same length and date, and the "Compare contents" option is not set, they are considered to be the same. 3) If two files have the same length and date, and the "Compare contents" option is set, then the files' status is the result of comparing their contents. 4) If two files have the same length and different dates, and the "Consolidate identical files" option is not set, they are considered to be different. 5) If two files have the same length and different dates, and the "Consolidate identical files" option is set, then the files' contents are compared. If the contents are different, the files are considered to be different (obviously). If the contents are the same, then a new "Transfer date" action is created for the files.
I think that the "Transfer date" operation should probably transfer the newer date to the older one. However, it might conceivably be useful sometimes to go the other way, in which case that could also be an option.
