Add option to synchronize directory timestamp

[giorgiob]

unison provides the -times option, which synchronizes modification times for files. I would find it useful to synchronize modification times for folders as well. This is possible with other tools, e.g. rsync.

(I could try and implement the feature myself and submit a patch, but I would need some hints regarding the place in the code where modification time synchronization is implemented, since I am not familiar with unison's source code.)

[bcpierce00]

This would be a nontrivial change, unfortunately -- the places you'd have to touch are spread across the change detection (update.ml), reconciliation (recon.ml), and propagation (transport.ml) phases, and some of the code is pretty complex.

[li-ruijie]

an option is to run rsync after unison to sync dir times but you have to be careful of the exceptions in your unison profile.

[giorgiob]

I am currently using rsync to synchronize between different computers. It requires some discipline because I always have to check out the current state from a server before I start working and then push the modification before I shut down my computer.

I would like to use unison instead because it allows to choose interactively how to reconcile individual files and their properties (including the files' timestamps). Unfortunately I cannot reconcile folder timestamps in the same way and this means that after reconciling a folder from different computers, the folder timestamp will not be the time I last worked on that folder but the time I last reconciled it.

I have looked into the code and indeed it is quite complex and I am afraid that at the moment I cannot invest enough time to contribute something meaningful. If I get some more time to work on this I will give it another try.

[HaleTom]

Workaround: afterwards, run:

rsync -r --times --size-only --existing

[protist]

The problem with using vanilla rsync is that it won't sync bidirectionally, which is the main strength of unison.