Re: [PATCH v2 6/7] add: warn when pathspec only matches SKIP_WORKTREE entries

[Matheus Tavares <matheus.bernardino@usp.br>]

On Wed, Feb 24, 2021 at 3:50 AM Elijah Newren <newren@gmail.com> wrote:
>
> On Tue, Feb 23, 2021 at 8:05 PM Matheus Tavares
> <matheus.bernardino@usp.br> wrote:
> >
> > +void advise_on_updating_sparse_paths(struct string_list *pathspec_list)
> > +{
> > +       struct string_list_item *item;
> > +
> > +       if (!pathspec_list->nr)
> > +               return;
> > +
> > +       fprintf(stderr, _("The following pathspecs only matched index entries outside the current\n"
> > +                         "sparse checkout:\n"));
> > +       for_each_string_list_item(item, pathspec_list)
> > +               fprintf(stderr, "%s\n", item->string);
>
> Was the use of fprintf(stderr, ...) because of the fact that you want
> to do multiple print statements?  I'm just curious if that was the
> reason for avoiding the warning() function, or if there was another
> consideration at play as well.

Yes, that was one of the reasons. The other was to use the same style as
the ignored files message, which doesn't print the "warning:" prefix.
But I don't have any strong preference here, I'd be OK with using
warning() too.

> > -static void refresh(int verbose, const struct pathspec *pathspec)
> > +static int refresh(int verbose, const struct pathspec *pathspec)
> >  {
> >         char *seen;
> > -       int i;
> > +       int i, ret = 0;
> > +       char *skip_worktree_seen = NULL;
> > +       struct string_list only_match_skip_worktree = STRING_LIST_INIT_NODUP;
> > +       int flags = REFRESH_DONT_MARK_SPARSE_MATCHES |
> > +                   (verbose ? REFRESH_IN_PORCELAIN : REFRESH_QUIET);
> >
> >         seen = xcalloc(pathspec->nr, 1);
> > -       refresh_index(&the_index, verbose ? REFRESH_IN_PORCELAIN : REFRESH_QUIET,
> > -                     pathspec, seen, _("Unstaged changes after refreshing the index:"));
> > +       refresh_index(&the_index, flags, pathspec, seen,
> > +                     _("Unstaged changes after refreshing the index:"));
> >         for (i = 0; i < pathspec->nr; i++) {
> > -               if (!seen[i])
> > -                       die(_("pathspec '%s' did not match any files"),
> > -                           pathspec->items[i].original);
> > +               if (!seen[i]) {
> > +                       if (matches_skip_worktree(pathspec, i, &skip_worktree_seen)) {
> > +                               string_list_append(&only_match_skip_worktree,
> > +                                                  pathspec->items[i].original);
> > +                       } else {
> > +                               die(_("pathspec '%s' did not match any files"),
> > +                                   pathspec->items[i].original);
> > +                       }
> > +               }
> > +       }
> > +
> > +       if (only_match_skip_worktree.nr) {
> > +               advise_on_updating_sparse_paths(&only_match_skip_worktree);
> > +               ret = 1;
> >         }
>
> On first reading, I missed that the code die()s if there are any
> non-SKIP_WORKTREE entries matched, and that is the reason you know
> that only SKIP_WORKTREE entries could have been matched for this last
> if-statement.

Hmm, I may be misinterpreting your explanation, but I think the
reasoning is slightly different. The code die()s if there are _no_
matches either among sparse or dense entries. The reason why we know
that only sparse entries matched the pathspecs in this last if-statement
is because the `only_match_skip_worktree` list is only appended when a
pathspec is not marked on seen[] (dense entries only), but it is marked
on skip_worktree_seen[] (sparse entries only).

> Hmm...here's an interesting command sequence:
>
> git init lame
> cd lame
> mkdir baz
> touch baz/tracked
> git add baz/tracked
> git update-index --skip-worktree baz/tracked
> rm baz/tracked.  # But leave the empty directory!
> echo baz >.gitignore
> git add --ignore-missing --dry-run baz
>
>
> Reports the following:
> """
> The following pathspecs only matched index entries outside the current
> sparse checkout:
> baz
> hint: Disable or modify the sparsity rules if you intend to update such entries.
> hint: Disable this message with "git config advice.updateSparsePath false"
> The following paths are ignored by one of your .gitignore files:
> baz
> hint: Use -f if you really want to add them.
> hint: Turn this message off by running
> hint: "git config advice.addIgnoredFile false"
> """

That's interesting. You can also trigger this behavior with a plain add
(i.e. without "--ignore-missing --dry-run").

Since we only get the list of ignored paths from fill_directory(), we
can't really tell whether a specific pathspec item had matches among
ignored files or not. If we had this information, we could conditionally
skip the sparse warning.

I.e. something like this (WARNING: hacky and just briefly tested):

diff --git a/builtin/add.c b/builtin/add.c
index fde6462850..90614e7e76 100644
--- a/builtin/add.c
+++ b/builtin/add.c
@@ -597,3 +597,3 @@ int cmd_add(int argc, const char **argv, const char *prefix)
 		int i;
-		char *skip_worktree_seen = NULL;
+		char *skip_worktree_seen = NULL, *ignored_seen = NULL;
 		struct string_list only_match_skip_worktree = STRING_LIST_INIT_NODUP;
@@ -621,3 +621,14 @@ int cmd_add(int argc, const char **argv, const char *prefix)

-			if (matches_skip_worktree(&pathspec, i, &skip_worktree_seen)) {
+			if (dir.ignored_nr) {
+				int j, prefix_len = common_prefix_len(&pathspec);
+				ignored_seen = xcalloc(pathspec.nr, 1);
+				for (j = 0; j < dir.ignored_nr; j++) {
+					dir_path_match(&the_index, dir.ignored[j],
+						       &pathspec, prefix_len,
+						       ignored_seen);
+				}
+			}
+
+			if (ignored_seen && !ignored_seen[i] &&
+			    matches_skip_worktree(&pathspec, i, &skip_worktree_seen)) {
 				string_list_append(&only_match_skip_worktree,
diff --git a/dir.c b/dir.c
index d153a63bbd..a19bc7aa0b 100644
--- a/dir.c
+++ b/dir.c
@@ -136,3 +136,3 @@ static int fnmatch_icase_mem(const char *pattern, int patternlen,

-static size_t common_prefix_len(const struct pathspec *pathspec)
+size_t common_prefix_len(const struct pathspec *pathspec)
 {
diff --git a/dir.h b/dir.h
index facfae4740..aa2d4aa71b 100644
--- a/dir.h
+++ b/dir.h
@@ -355,2 +355,3 @@ int simple_length(const char *match);
 int no_wildcard(const char *string);
+size_t common_prefix_len(const struct pathspec *pathspec);
 char *common_prefix(const struct pathspec *pathspec);


Now `git add baz` would only produce:

The following paths are ignored by one of your .gitignore files:
baz
hint: Use -f if you really want to add them.
hint: Turn this message off by running
hint: "git config advice.addIgnoredFile false"