Re: [PATCH] Teach "git apply" to prepend a prefix with "--root=<root>"

> Johannes Schindelin <Johannes.Schindelin@gmx.de> writes:
> 
> > With "git apply --root=<root>", all file names in the patch are prepended
> > with <root>.  If a "-p" value was given, the paths are stripped _before_
> > prepending <root>.
> 
> > @@ -182,6 +182,10 @@ behavior:
> >  	by inspecting the patch (e.g. after editing the patch without
> >  	adjusting the hunk headers appropriately).
> >  
> > +--root=<root>::
> > +	Prepend <root> to all filenames.  If a "-p" argument was passed, too,
> > +	it is applied before prepending the new root.
> > +
> 
> I looked for precedence of this concept outside git but did not find
> anything that exactly matched.
> 
> The -p<num> came from patch where it is also called --strip=num.  This 
> new option --root is about the reverse operation and it is about 
> inserting at the beginning --- it is rerooting, in other words, but then 
> --root is good enough and shorter.  mkisofs uses the word "graft" when 
> it allows tree shifting (enabled with --graft-points), but the word 
> "graft" means a totally different thing to us, so we would not want to 
> use that word.
> 
> I am not complaining (--root is fine by me), but just thinking aloud, 
> hoping somebody's brainwave is provoked while reading this babbling and 
> comes up with a better wording ;-).

> > diff --git a/builtin-apply.c b/builtin-apply.c
> > index 9fcfe39..d56d913 100644
> > --- a/builtin-apply.c
> > +++ b/builtin-apply.c
> > @@ -58,6 +58,8 @@ static int whitespace_error;
> > @@ -3240,6 +3252,18 @@ int cmd_apply(int argc, const char **argv, const char *unused_prefix)
> >  			options |= RECOUNT;
> >  			continue;
> >  		}
> > +		if (!strncmp(arg, "--root=", strlen("--root="))) {
> 
> prefixcmp()?

> > +			arg += strlen("--root=");
> > +			root_len = strlen(arg);
> > +			if (root_len && arg[root_len + 1] != '/') {
> 
> Ah, being nice not to force trailing slash on users --- how unlike you 
> ;-)