Re: BUG: wildmatches like foo/**/**/bar don't match properly due to internal optimizations

> On Wed, Apr 26, 2017 at 2:13 AM, Ævar Arnfjörð Bjarmason
> <avarab@gmail.com> wrote:
> > Thought I'd just start another thread for this rather than tack it
> > onto the pathalogical case thread.
> >
> > In commit 4c251e5cb5 ("wildmatch: make /**/ match zero or more
> > directories", 2012-10-15) Duy added support for ** in globs.
> >
> > One test-case for this is:
> >
> >     match 1 0 'foo/baz/bar' 'foo/**/**/bar'
> >
> > I.e. foo/**/**/bar matches foo/baz/bar. However due to some
> > pre-pruning we do in pathspec/ls-tree we can't ever match it, because
> > the first thing we do is peel the first part of the path/pattern off,
> > i.e. foo/, and then match baz/bar against **/**/bar.
> 
> Yeah. I think the prefix compare trick predated wildmatch. When I
> introduced positional wildcards "**/" I failed to spot this. Good
> catch.
> 
> Ideally this sort of optimization should be contained within wildmatch
> (or whatever matching engine we'll be using). It also opens up more
> opportunity (like precompile pattern mentioned elsewhere in this
> thread).
> 
> You need to be careful though, when we do case-insensitive matching,
> sometimes we want to match the prefix case _sensitively_ instead. So
> we need to pass the "prefix" info in some cases to the matching
> engine.
> 
> I guess time is now ripe (i.e. somebody volunteers to work on this ;-)
> to improve wildmatch. "improve" can also be "rewriting to pcre" if we
> really want that route, which I have no opinion because I don't know
> pcre availability on other (some obscure) platforms.