pull: drop confusing prefix parameter of die_on_unclean_work_tree()

In cmd_pull(), when verifying that there are no changes preventing a
rebasing pull, we diligently pass the prefix parameter to the
die_on_unclean_work_tree() function which in turn diligently passes it
to the has_unstaged_changes() and has_uncommitted_changes() functions.

The casual reader might now be curious (as this developer was) whether
that means that calling `git pull --rebase` in a subdirectory will
ignore unstaged changes in other parts of the working directory. And be
puzzled that `git pull --rebase` (correctly) complains about those
changes outside of the current directory.

The puzzle is easily resolved: while we take pains to pass around the
prefix and even pass it to init_revisions(), the fact that no paths are
passed to init_revisions() ensures that the prefix is simply ignored.

That, combined with the fact that we will *always* want a *full* working
directory check before running a rebasing pull, is reason enough to
simply do away with the actual prefix parameter and to pass NULL
instead, as if we were running this from the top-level working directory
anyway.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/pull.c

@@ -328,12 +328,12 @@ static int git_pull_config(const char *var, const char *value, void *cb)
 /**
  * Returns 1 if there are unstaged changes, 0 otherwise.
  */
-static int has_unstaged_changes(const char *prefix)
+static int has_unstaged_changes(void)
 {
 	struct rev_info rev_info;
 	int result;
 
-	init_revisions(&rev_info, prefix);
+	init_revisions(&rev_info, NULL);
 	DIFF_OPT_SET(&rev_info.diffopt, IGNORE_SUBMODULES);
 	DIFF_OPT_SET(&rev_info.diffopt, QUICK);
 	diff_setup_done(&rev_info.diffopt);
@@ -344,7 +344,7 @@ static int has_unstaged_changes(const char *prefix)
 /**
  * Returns 1 if there are uncommitted changes, 0 otherwise.
  */
-static int has_uncommitted_changes(const char *prefix)
+static int has_uncommitted_changes(void)
 {
 	struct rev_info rev_info;
 	int result;
@@ -352,7 +352,7 @@ static int has_uncommitted_changes(const char *prefix)
 	if (is_cache_unborn())
 		return 0;
 
-	init_revisions(&rev_info, prefix);
+	init_revisions(&rev_info, NULL);
 	DIFF_OPT_SET(&rev_info.diffopt, IGNORE_SUBMODULES);
 	DIFF_OPT_SET(&rev_info.diffopt, QUICK);
 	add_head_to_pending(&rev_info);
@@ -365,7 +365,7 @@ static int has_uncommitted_changes(const char *prefix)
  * If the work tree has unstaged or uncommitted changes, dies with the
  * appropriate message.
  */
-static void die_on_unclean_work_tree(const char *prefix)
+static void die_on_unclean_work_tree(void)
 {
 	struct lock_file *lock_file = xcalloc(1, sizeof(*lock_file));
 	int do_die = 0;
@@ -375,12 +375,12 @@ static void die_on_unclean_work_tree(const char *prefix)
 	update_index_if_able(&the_index, lock_file);
 	rollback_lock_file(lock_file);
 
-	if (has_unstaged_changes(prefix)) {
+	if (has_unstaged_changes()) {
 		error(_("Cannot pull with rebase: You have unstaged changes."));
 		do_die = 1;
 	}
 
-	if (has_uncommitted_changes(prefix)) {
+	if (has_uncommitted_changes()) {
 		if (do_die)
 			error(_("Additionally, your index contains uncommitted changes."));
 		else
@@ -875,7 +875,7 @@ int cmd_pull(int argc, const char **argv, const char *prefix)
 			die(_("Updating an unborn branch with changes added to the index."));
 
 		if (!autostash)
-			die_on_unclean_work_tree(prefix);
+			die_on_unclean_work_tree();
 
 		if (get_rebase_fork_point(rebase_fork_point, repo, *refspecs))
 			hashclr(rebase_fork_point);