Re: [PATCH 1/5] t7300: add testcase showing unnecessary traversal into ignored directory

[Elijah Newren <newren@gmail.com>]

On Fri, May 7, 2021 at 5:11 PM Eric Sunshine <sunshine@sunshineco.com> wrote:
>
> On Fri, May 7, 2021 at 8:04 PM Elijah Newren <newren@gmail.com> wrote:
> > I think I figured it out.  I now have the test simplified down to just:
> >
> > test_expect_success 'avoid traversing into ignored directories' '
> >     test_when_finished rm -f output error trace.* &&
> >     test_create_repo avoid-traversing-deep-hierarchy &&
> >     (
> >         mkdir -p untracked/subdir/with/a &&
> >         >untracked/subdir/with/a/random-file.txt &&
> >
> >         GIT_TRACE2_PERF="$TRASH_DIRECTORY/trace.output" \
> >         git clean -ffdxn -e untracked &&
> >
> >         grep data.*read_directo.*visited ../trace.output \
> >             | cut -d "|" -f 9 >../trace.relevant &&
> >         cat >../trace.expect <<-EOF &&
> >         directories-visited:1
> >         paths-visited:4
> >         EOF
> >         test_cmp ../trace.expect ../trace.relevant
> >     )
> > '
>
> I believe that you can close the subshell immediately after `git
> clean`, which would allow you to drop all the "../" prefixes on
> pathnames.

Ah, good point.  I'll make that fix.

> > This relies on a few extra changes to the code: (1) switching the
> > existing trace calls in dir.c over to using trace2 variants, and (2)
> > adding two new counters (visited_directories and visited_paths) that
> > are output using the trace2 framework.  I'm a little unsure if I
> > should check the paths-visited counter (will some platform have
> > additional files in every directory besides '.' and '..'?  Or not have
> > one of those?), but it is good to have it check that the code in this
> > case visits no directories other than the toplevel one (i.e. that
> > directories-visited is 1).
>
> I can't find the reference, but I recall a reply by jrneider (to some
> proposed patch) that not all platforms are guaranteed to have "." and
> ".." entries (but I'm not sure we need to worry about that presently).