Re: Using clean/smudge filters with difftool

[John Keeping <john@keeping.me.uk>]

On Thu, Jun 18, 2015 at 03:51:25PM +0200, Florian Aspart wrote:
> 2015-06-18 15:26 GMT+02:00 John Keeping <john@keeping.me.uk>:
> > [Please don't top-post on this list.]
> >
> > On Thu, Jun 18, 2015 at 03:15:38PM +0200, Florian Aspart wrote:
> >> 2015-06-18 14:31 GMT+02:00 Michael J Gruber <git@drmicha.warpmail.net>:
> >> > Florian Aspart venit, vidit, dixit 16.06.2015 16:11:
> >> >> Hi everyone,
> >> >>
> >> >> I created a clean filter to apply on some files before commiting them.
> >> >> The filter works correctly when I commit the file and is also applied
> >> >> when I usethe iff command line tool.
> >> >> However, when using difftool with meld, the filter is not applied and
> >> >> the different versions of the files are compared without any
> >> >> filtering.
> >> >>
> >> >> Is there a way to apply the clean/smudge filters when comparing the
> >> >> working copy of a file to the HEAD version in a gui diff tool?
> >> >>
> >> >> I'm using git version 2.4.3 under Ubuntu.
> >> >>
> >> >> Best,
> >> >> Florian
> >> >
> >> > Are you saying that "difftool" compares an uncleaned working tree file
> >> > with a cleaned blob? That would be a bug in either difftool or the way
> >> > we feed difftool.
> >> >
> >> yes in this case "difftool" compares an uncleaned working tree file
> >> with a cleaned blob. I did not try the smudge filter to see if it
> >> applied in difftool.
> >>
> >> I think the problem comes from the way difftool is feeded, since I
> >> also had this problem when setting an external tool for the diff in
> >> the gitconfig file.
> >>
> >> However, I'm not sure if this is a bug or it is designed to be so.
> >> If the external tool changes a cleaned working tree file during the
> >> diff, then by saving this file the result of the cleaning filter would
> >> also be saved in the working tree.
> >
> > How is your filter configured?  Is it using a simple pattern (e.g.
> > "*.c") or is it using a file path?
> >
> > git-difftool uses `git checkout-index --all --prefix=$dir/` and I wonder
> > if the prefix means that the attribute specification does not match the
> > temporary file that difftool produces, so no filter is applied.
> 
> It is using a simple pattern:
> *.ipynb filter=clean_ipynb

I also realised that the code for file diff is very different from
directory diff do you see any difference between git-difftool acting on
files and with the `--dir-diff` option?