git add: rework the logic to warn "git add <pathspec>..." default change

The earlier logic to warn against "git add subdir" that is run
without "-A" or "--no-all" was only to check any <pathspec> given
exactly spells a directory name that (still) exists on the
filesystem.  This had number of problems:

* "git add '*dir'" (note that the wildcard is hidden from the
shell) would not trigger the warning.

* "git add '*.py'" would behave differently between the current
version of Git and Git 2.0 for the same reason as "subdir", but
would not trigger the warning.

* "git add dir" for a submodule "dir" would just update the index
entry for the submodule "dir" without ever recursing into it, and
use of "-A" or "--no-all" would matter.  But the logic only
checks the directory-ness of "dir" and gives an unnecessary
warning.

Rework the logic to detect the case where the behaviour will be
different in Git 2.0, and issue a warning only when it matters.
Even with the code before this warning, "git add subdir" will have
to traverse the directory in order to find _new_ files the index
does not know about _anyway_, so we can do this check without adding
an extra pass to find if <pathspec> matches any removed file.

This essentially updates the "add_files_to_cache()" public API to
"update_files_in_cache()" API that is internal to "git add", because
with the "--all" option, the function is no longer about "adding"
paths to the cache, but is also used to remove them.

There are other callers of the former from "checkout" (used when
"checkout -m" prepares the temporary tree that represents the local
modifications to be merged) and "commit" ("commit --include" that
picks up local changes in addition to what is in the index).  Since
ADD_CACHE_IGNORE_ERRORS (aka "--no-all") is not used by either of
them, once dust settles after Git 2.0 and the warning becomes
unnecessary, we may want to unify these two functions again.

Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/builtin/add.c b/builtin/add.c
index f8f6c9ed34541a3ed3426c0922dfc70704efff65..4242bce6d8c4aa075c7523c970ed2442788f5ae3 100644 (file)
--- a/builtin/add.c
+++ b/builtin/add.c
@@ -26,6 +26,9 @@ static int take_worktree_changes;
 struct update_callback_data {
        int flags;
        int add_errors;
+
+       /* only needed for 2.0 transition preparation */
+       int warn_add_would_remove;
 };
 
 static int fix_unmerged_status(struct diff_filepair *p,
@@ -49,6 +52,17 @@ static int fix_unmerged_status(struct diff_filepair *p,
                return DIFF_STATUS_MODIFIED;
 }
 
+static void warn_add_would_remove(const char *path)
+{
+       warning(_("In Git 2.0, 'git add <pathspec>...' will also update the\n"
+                 "index for paths removed from the working tree that match\n"
+                 "the given pathspec. If you want to 'add' only changed\n"
+                 "or newly created paths, say 'git add --no-all <pathspec>...'"
+                 " instead.\n\n"
+                 "'%s' would be removed from the index without --no-all."),
+               path);
+}
+
 static void update_callback(struct diff_queue_struct *q,
                            struct diff_options *opt, void *cbdata)
 {
@@ -70,6 +84,10 @@ static void update_callback(struct diff_queue_struct *q,
                        }
                        break;
                case DIFF_STATUS_DELETED:
+                       if (data->warn_add_would_remove) {
+                               warn_add_would_remove(path);
+                               data->warn_add_would_remove = 0;
+                       }
                        if (data->flags & ADD_CACHE_IGNORE_REMOVAL)
                                break;
                        if (!(data->flags & ADD_CACHE_PRETEND))
@@ -81,20 +99,27 @@ static void update_callback(struct diff_queue_struct *q,
        }
 }
 
-int add_files_to_cache(const char *prefix, const char **pathspec, int flags)
+static void update_files_in_cache(const char *prefix, const char **pathspec,
+                                 struct update_callback_data *data)
 {
-       struct update_callback_data data;
        struct rev_info rev;
        init_revisions(&rev, prefix);
        setup_revisions(0, NULL, &rev, NULL);
        init_pathspec(&rev.prune_data, pathspec);
        rev.diffopt.output_format = DIFF_FORMAT_CALLBACK;
        rev.diffopt.format_callback = update_callback;
-       data.flags = flags;
-       data.add_errors = 0;
-       rev.diffopt.format_callback_data = &data;
+       rev.diffopt.format_callback_data = data;
        rev.max_count = 0; /* do not compare unmerged paths with stage #2 */
        run_diff_files(&rev, DIFF_RACY_IS_MODIFIED);
+}
+
+int add_files_to_cache(const char *prefix, const char **pathspec, int flags)
+{
+       struct update_callback_data data;
+
+       memset(&data, 0, sizeof(data));
+       data.flags = flags;
+       update_files_in_cache(prefix, pathspec, &data);
        return !!data.add_errors;
 }
 
@@ -354,18 +379,6 @@ static void warn_pathless_add(const char *option_name, const char *short_name) {
                option_name, short_name);
 }
 
-static int directory_given(int argc, const char **argv)
-{
-       struct stat st;
-
-       while (argc--) {
-               if (!lstat(*argv, &st) && S_ISDIR(st.st_mode))
-                       return 1;
-               argv++;
-       }
-       return 0;
-}
-
 int cmd_add(int argc, const char **argv, const char *prefix)
 {
        int exit_status = 0;
@@ -378,6 +391,7 @@ int cmd_add(int argc, const char **argv, const char *prefix)
        char *seen = NULL;
        const char *option_with_implicit_dot = NULL;
        const char *short_option_with_implicit_dot = NULL;
+       struct update_callback_data update_data;
 
        git_config(add_config, NULL);
 
@@ -403,15 +417,11 @@ int cmd_add(int argc, const char **argv, const char *prefix)
 
        /*
         * Warn when "git add pathspec..." was given without "-u" or "-A"
-        * and pathspec... contains a directory name.
+        * and pathspec... covers a removed path.
         */
-       if (!take_worktree_changes && addremove_explicit < 0 &&
-           directory_given(argc, argv))
-               warning(_("In Git 2.0, 'git add <pathspec>...' will also update the\n"
-                         "index for paths removed from the working tree that match\n"
-                         "the given pathspec. If you want to 'add' only changed\n"
-                         "or newly created paths, say 'git add --no-all <pathspec>...'"
-                         " instead."));
+       memset(&update_data, 0, sizeof(update_data));
+       if (!take_worktree_changes && addremove_explicit < 0)
+               update_data.warn_add_would_remove = 1;
 
        if (!take_worktree_changes && addremove_explicit < 0 && argc)
                /*
@@ -508,8 +518,10 @@ int cmd_add(int argc, const char **argv, const char *prefix)
 
        plug_bulk_checkin();
 
-       exit_status |= add_files_to_cache(prefix, pathspec, flags);
+       update_data.flags = flags;
+       update_files_in_cache(prefix, pathspec, &update_data);
 
+       exit_status |= !!update_data.add_errors;
        if (add_new_files)
                exit_status |= add_files(&dir, flags);