From: "Omar Polo" <op@omarpolo.com>
Subject: Re: got diff vs file names with whitespaces
To: Stefan Sperling <stsp@stsp.name>
Cc: gameoftrees@openbsd.org
Date: Fri, 06 Nov 2026 15:51:29 +0100

Stefan Sperling <stsp@stsp.name> wrote:
> On Fri, Nov 06, 2026 at 01:00:51PM +0100, Omar Polo wrote:
> > Stefan Sperling <stsp@stsp.name> wrote:
> > > On Thu, Nov 05, 2026 at 09:56:20PM +0100, Omar Polo wrote:
> > > > @@ -252,8 +253,9 @@ output_unidiff_chunk(struct diff_output_info *outinfo,
> > > >  	}
> > > >  
> > > >  	if (print_header && !(state->header_printed)) {
> > > > -		rc = fprintf(dest, "--- %s\n",
> > > > -		    diff_output_get_label_left(info));
> > > > +		label = diff_output_get_label_left(info);
> > > > +		rc = fprintf(dest, "--- %s%s\n", label,
> > > > +		    strchr(label, ' ') != NULL ? "\t" : "");
> > > 
> > > 'svn diff' always writes a tab here, no matter what the pathname contains.
> > > I suspect we could do the same?
> > 
> > done =)
> 
> Hmm, I got a bit mixed up here because "label" refers to different
> things between implementations.
> 
> In 'svn diff' the label is something like "(working copy)" or
> "(revision 123)", which is extra information following the path,
> separated from the path by a tab.
> 
> So the format used by 'svn diff' is: --- path\t(working copy)"
> And because 'svn diff' always adds a label, it always prints a tab
> after printing the path.

diff(1) is the same, only it prints the date (mtime i think) of the
file.

> Now, 'got diff' never showed an extra label, only the path (which our diff
> implementations calls "label" so this is where things get confusing). And
> since we only print a path there was so far no reason to print a tab, right?

nope :)

> Is Larry patch trying to detect cases like "--- path (working copy)" (no \t)
> and then tries to cleverly strip everything to leave just the "path" part?
> Such that paths are truncated if they contain spaces without a trailing tab?

bingo

our patch doesn't care, and just splits on tab, which i think it's fine.

git diff does what i was doing in my first diff, i.e. add the trailing
tab only when the file name contains a space.

i don't mind adding it always, especially after the pain of fixing all
the regress :P

> If that is the case I still think we should print the trailing tab since it
> helps patch commands do the right thing with the path name.
> 
> Or am I misunderstanding the problem?
> 
> > what i was very close to forget is that we need to commit the diff part
> > before in diff.git and then sync it, right?
> 
> Ideally, yes. But we can also sync the other way around.

if okay i'll do the commit on diff.git first, then sync and add the
regress at the same time.