On 05/25/2016 07:22 PM, Eli Zaretskii wrote:

> I think we can make an educated guess, see below.  My conclusion is
> that this does need to be VCS-specific.
>
>> So far, we've seem some pretty similar results with vc-diff using Git, Hg and RCS.
>
> Not quite.  They all fail, but in different ways.  More importantly,
> the solutions are most probably going to be different.

OK, that makes sense.

> Backend-specific, most probably.  Except that currently we only have a
> good idea about the Git backend, for which it is explicitly documented
> that the output will be in UTF-8 when content filters are used.
>
> ...

Taking a step back, I'm not sure it's really necessary to fix this. 
Because Uwe, the only person to complain about diffing UTF-16 files so 
far, can solve it much easier by switching the file to UTF-8.

And properly fixing it, across the board, is either impossible, or at 
least pretty hard.

>> We can always extract a new function when it's needed, though.
>
> True, but I think if we want to support UTF-16 files, the need is
> already here.  vc-diff and its derivatives are just the tip of the
> iceberg, we will need similar stuff for every command that includes
> both text from the versioned file(s) and some text output by the VCS
> program itself.

Here's a patch everybody is welcome to try.