Re: Git should preserve modification times at least on request

From: Peter Backes <rtc@helen.plasma.xg8.de>
Date: Feb 20, 2018, 22:48 UTC
Message-ID: <20180220224808.GA25678@helen.PLASMA.Xg8.DE>
In-Reply-To: <nycvar.QRO.7.76.6.1802202329540.31@ZVAVAG-6OXH6DA.rhebcr.pbec.zvpebfbsg.pbz>

On Tue, Feb 20, 2018 at 11:32:23PM +0100, Johannes Schindelin wrote:

Show 13 quoted lines

> Hi Peter,
> 
> On Tue, 20 Feb 2018, Peter Backes wrote:
> 
> > On Tue, Feb 20, 2018 at 11:46:38AM +0100, Johannes Schindelin wrote:
> > 
> > > I would probably invent a file format (`<mtime><TAB><path><LF>`)
> > 
> > I'm stuck there because of <path> being munged.
> 
> From which command do you want to get it? If you are looking at `git
> diff`, you may want to use the `-z --name-only` options to avoid munging
> the paths.

I plan to use "git diff-tree --name-only $w_tree HEAD" and subtract all lines from "git diff-index --name-only HEAD" to get the files for which the timestamp should be stored..

If I use "-z" I get the non-munged path, but I cannot safely store such paths in the proposed file format; they might contain newlines (sigh). So at one point I have to munge. Then the same question arises when I have to get the actual path from the munged path when restoring the timestamps.

If there's no ready-made functionality to munge and unmunge paths, I have to write some awk for this. At first I thought this might add one more dependency to git, but it seems that awk is already used in git-mergetool.sh, so I suppose it's okay to use in git-stash.sh etc, too.

Best wishes Peter

-- 
Peter Backes, rtc@helen.PLASMA.Xg8.DE