Re: [PATCH v2 2/2] t7063: mtime-mangling instead of delays in untracked cache testing

[Tao Klerks <tao@klerks.biz>]

On Tue, Mar 1, 2022 at 7:03 PM Junio C Hamano <gitster@pobox.com> wrote:
>
> "Tao Klerks via GitGitGadget" <gitgitgadget@gmail.com> writes:
>
> > +chmtime_worktree_root () {
> > +     # chmtime doesnt handle relative paths on windows, so need
> > +     # to "hardcode" a reference to the worktree folder name.
> > +     test-tool -C .. chmtime $1 worktree
> > +}
> > +
>
> Enclose $1 in a pair of double-quotes to help readers.  They do not
> have to wonder if the caller is interested in (or has to worry
> about) triggering word splitting at $IFS if you did so.

Absolutely, thx.

>
> >  avoid_racy() {
> >       sleep 1
> >  }
> > @@ -90,6 +96,9 @@ test_expect_success 'setup' '
> >       cd worktree &&
> >       mkdir done dtwo dthree &&
> >       touch one two three done/one dtwo/two dthree/three &&
> > +     test-tool chmtime =-300 one two three done/one dtwo/two dthree/three &&
> > +     test-tool chmtime =-300 done dtwo dthree &&
> > +     chmtime_worktree_root =-300 &&
>
> I am wondering if it is better to spelling it out like this:
>
>         test-tool -C.. chmtime =-300 worktree &&
>
> instead of hiding the fact that "../worktree" is being touched
> behind a one-line helper.  Being able to explicitly write "worktree"
> in the context that this particular code path uses the "worktree"
> directory is a big plus, but at the same time, bypassing the helper
> makes it unclear why we just don't chmtime "../worktree", and will
> strongly tempt future developers into breaking it, so, I dunno.
>
> What's the reason why utime() works only on a path in the current
> directory and cannot take "../worktree" again? If we cannot solve
> that, I guess an extra helper with a big comment, like we see in
> this patch, would be the least bad solution.
>

Heh. It didn't work, in my initial tests. Now it does. It turns out I was
initially getting the directory handle with
"FILE_WRITE_DATA | FILE_WRITE_ATTRIBUTES", and
everything worked except modifying the current folder via a relative
path expression, which yielded a "Permission denied" error. I
worked around it by explicitly changing the current directory...

Then I realized FILE_WRITE_DATA wasn't necessary (but didn't
connect the dots). Then you noted the "-C .." arg to test-tool
(and I still didn't connect the dots).

The problem was never relative paths, but rather trying to get a
writable handle to the current directory. The only reason "-C .."
worked was that I already stopped trying to get a writable handle.

I have no idea what it means to get a writable handle to a
directory, but apparently you can't do it for your current
directory. Now I know.

Thanks for the nudge, this is all clean now.