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

Junio C Hamano [off-list ref] 于2021年1月21日周四 上午5:26写道：

"ZheNing Hu via GitGitGadget" [off-list ref] writes:

quoted

@@ -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.

quoted

              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 :)

quoted

                      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.

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).

quoted

              }
              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.

quoted

              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...

quoted

+             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.

quoted

      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!