Re: [PATCH v5 3/3] ls-files.c: add --deduplicate option

From: 胡哲宁 <adlternative@gmail.com>
Date: Jan 21, 2021, 11:00 UTC
Message-ID: <CAOLTT8R=fF00WCVBSTDKHG_3p5RcZaxM2AU-cUj1sNWvy=mhCQ@mail.gmail.com>
In-Reply-To: <xmqq7do7fggn.fsf@gitster.c.googlers.com>

Junio C Hamano <gitster@pobox.com> 于2021年1月21日周四 上午5:26写道：

Show 12 quoted lines

>
> "ZheNing Hu via GitGitGadget" <gitgitgadget@gmail.com> writes:
>
> > @@ -321,30 +324,46 @@ static void show_files(struct repository *repo, struct dir_struct *dir)
> >
> >               construct_fullname(&fullname, repo, ce);
> >
> > +             if (skipping_duplicates && last_shown_ce &&
> > +                     !strcmp(last_shown_ce->name,ce->name))
> > +                             continue;
>
> Style.  Missing SP after comma.

Get it.

Show 16 quoted lines

>
> >               if ((dir->flags & DIR_SHOW_IGNORED) &&
> >                       !ce_excluded(dir, repo->index, fullname.buf, ce))
> >                       continue;
> >               if (ce->ce_flags & CE_UPDATE)
> >                       continue;
> >               if (show_cached || show_stage) {
> > +                     if (skipping_duplicates && last_shown_ce &&
> > +                             !strcmp(last_shown_ce->name,ce->name))
> > +                                     continue;
>
> OK.  When show_stage is set, skipping_duplicates is automatically
> turned off (and show_unmerged is automatically covered as it turns
> show_stage on automatically).  So this feature has really become
> "are we showing only names, and if so, did we show an entry of the
> same name before?".

Yeah,showing only names,so I yesterday ask such question :)

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>
> >                       if (!show_unmerged || ce_stage(ce))
> >                               show_ce(repo, dir, ce, fullname.buf,
> >                                       ce_stage(ce) ? tag_unmerged :
> >                                       (ce_skip_worktree(ce) ? tag_skip_worktree :
> >                                               tag_cached));
> > +                     if (show_cached && skipping_duplicates)
> > +                             last_shown_ce = ce;
>
> The code that calls show_ce() belonging to a totally separate if()
> statement makes my stomach hurt---how are we going to guarantee that
> "last shown" really will keep track of what was shown last?
>
> Shouldn't the above be more like this?
>
> -                       if (!show_unmerged || ce_stage(ce))
> +                       if (!show_unmerged || ce_stage(ce)) {
>                                 show_ce(repo, dir, ce, fullname.buf,
>                                         ce_stage(ce) ? tag_unmerged :
>                                         (ce_skip_worktree(ce) ? tag_skip_worktree :
>                                                 tag_cached));
> +                               last_shown_ce = ce;
> +                       }
>

well,I am also thinking about this question :"last_shown_ce" is not true
last shown ce,but may be If "last_shown_ce" truly seen every last shown
ce ,We may need more cumbersome logic to make the program correct.
I have tried the processing method of your above code before, but found
 that some errors may have occurred.

Show 42 quoted lines

> It does maintain last_shown_ce even when skipping_duplicates is not
> set, but I think that is overall win.  Assigning unconditionally
> would be cheaper than making a conditional jump on the variable and
> make assignment (or not).
>
> >               }
> >               if (ce_skip_worktree(ce))
> >                       continue;
> > +             if (skipping_duplicates && last_shown_ce &&
> > +                     !strcmp(last_shown_ce->name,ce->name))
> > +                             continue;
>
> Style.  Missing SP after comma.
>
> OK, if we've shown an entry of the same name under skip-duplicates
> mode, and the code that follows will show the same entry (if they
> decide to show it), so we can go to the next entry early.
>
> >               err = lstat(fullname.buf, &st);
> >               if (err) {
> > -                     if (errno != ENOENT && errno != ENOTDIR)
> > -                             error_errno("cannot lstat '%s'", fullname.buf);
> > -                     if (show_deleted)
> > +                     if (skipping_duplicates && show_deleted && show_modified)
> >                               show_ce(repo, dir, ce, fullname.buf, tag_removed);
> > -                     if (show_modified)
> > -                             show_ce(repo, dir, ce, fullname.buf, tag_modified);
> > +                     else {
> > +                             if (errno != ENOENT && errno != ENOTDIR)
> > +                                     error_errno("cannot lstat '%s'", fullname.buf);
> > +                             if (show_deleted)
> > +                                     show_ce(repo, dir, ce, fullname.buf, tag_removed);
> > +                             if (show_modified)
> > +                                     show_ce(repo, dir, ce, fullname.buf, tag_modified);
> > +                     }
> >               } else if (show_modified && ie_modified(repo->index, ce, &st, 0))
> >                       show_ce(repo, dir, ce, fullname.buf, tag_modified);
>
> This part will change shape quite a bit when we follow the
> suggestion I made on 1/3, so I won't analyze how correct this
> version is.
>

Fine...

Show 26 quoted lines

> > +             last_shown_ce = ce;
> >       }
> >
> >       strbuf_release(&fullname);
> > @@ -571,6 +590,7 @@ int cmd_ls_files(int argc, const char **argv, const char *cmd_prefix)
> >                       N_("pretend that paths removed since <tree-ish> are still present")),
> >               OPT__ABBREV(&abbrev),
> >               OPT_BOOL(0, "debug", &debug_mode, N_("show debugging data")),
> > +             OPT_BOOL(0,"deduplicate",&skipping_duplicates,N_("suppress duplicate entries")),
> >               OPT_END()
> >       };
> >
> > @@ -610,6 +630,8 @@ int cmd_ls_files(int argc, const char **argv, const char *cmd_prefix)
> >                * you also show the stage information.
> >                */
> >               show_stage = 1;
> > +     if (show_tag || show_stage)
> > +             skipping_duplicates = 0;
>
> OK.
>
> >       if (dir.exclude_per_dir)
> >               exc_given = 1;
> >
>
> Thanks.

Thanks,Junio,I find my PR in gitgitgadget have been accepted. By the way, I found the problem "leftoverbit" and "good first issue" on gitgitgadget It may not have been updated for a long time, and most of the above may have been resolved.

Should it do an update? Then we can happily be a "bounty hunter" in the git community, haha!