[PATCH 1.8.0] add: make "add -u" update full tree without pathspec

["Nguyễn Thái Ngọc Duy" <pclouds@gmail.com>]

When -u was introduced in dfdac5d (git-add -u: match the index with
working tree., 2007-04-20), "add -u" (without pathspec) added
everything. Shortly after, 2ed2c22 (git-add -u paths... now works from
subdirectory, 2007-08-16) broke it while fixing something related.

This makes -u (and -A) inconsistent with some other options, namely -p.
It's been four years since the unintentional breakage and people are
probably used to "git add -u" updating only current directory. Perhaps
it's time to bring the original behavior back? Current behavior can
always be achieved with "git add -u ."

Migration plan:

I'm bad at this. Can we start with a patch that warns users to do "git
add -u ." when they do "git add -u"? Hopefully they would have their
fingers retraied by the time the behavior is changed in 1.8.0.

PS. What about -A?

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 2011/2/7 Sebastian Pipping <webmaster@hartwork.org>:
 >> git add -u was tree-wide when it was introduced in dfdac5d (git-add
 >> -u: match the index with working tree., 2007-04-20), but 2ed2c22
 >> (git-add -u paths... now works from subdirectory, 2007-08-16) broke it
 >> while fixing something related.
 >
 > So my memory didn't fool me.  Thanks for digging this out.
 >
 > Can we have tree-wide "git add -u" back, please?

 Yup yup I like it too (and wanted the original behavior sometimes, even
 though I didn't know it was original behavior).

 Pulling Junio in for -A. It seems closely related to -u. In fact I revert
 one line from 1e5f764 (builtin-add.c: optimize -A option and "git add ."
 - 2008-07-22) but not fully understand why it was changed.

 builtin/add.c         |    7 +++++--
 t/t2200-add-update.sh |   13 +++++++------
 2 files changed, 12 insertions(+), 8 deletions(-)

diff --git a/builtin/add.c b/builtin/add.c
index 12b964e..f1f8b5a 100644
--- a/builtin/add.c
+++ b/builtin/add.c
@@ -389,7 +389,7 @@ int cmd_add(int argc, const char **argv, const char *prefix)
 		die("-A and -u are mutually incompatible");
 	if (!show_only && ignore_missing)
 		die("Option --ignore-missing can only be used together with --dry-run");
-	if ((addremove || take_worktree_changes) && !argc) {
+	if (addremove && !argc) {
 		static const char *here[2] = { ".", NULL };
 		argc = 1;
 		argv = here;
@@ -412,7 +412,10 @@ int cmd_add(int argc, const char **argv, const char *prefix)
 		fprintf(stderr, "Maybe you wanted to say 'git add .'?\n");
 		return 0;
 	}
-	pathspec = validate_pathspec(argc, argv, prefix);
+	if (take_worktree_changes && !argc)
+		pathspec = NULL;
+	else
+		pathspec = validate_pathspec(argc, argv, prefix);
 
 	if (read_cache() < 0)
 		die("index file corrupt");
diff --git a/t/t2200-add-update.sh b/t/t2200-add-update.sh
index 0692427..2201242 100755
--- a/t/t2200-add-update.sh
+++ b/t/t2200-add-update.sh
@@ -69,15 +69,16 @@ test_expect_success 'cache tree has not been corrupted' '
 test_expect_success 'update from a subdirectory' '
 	(
 		cd dir1 &&
-		echo more >sub2 &&
+		echo more >>sub2 &&
 		git add -u sub2
-	)
-'
-
-test_expect_success 'change gets noticed' '
-
+	) &&
 	test "$(git diff-files --name-status dir1)" = ""
+'
 
+test_expect_success 'update without args from subdir' '
+	echo more >>top &&
+	( cd dir1 && git add -u ) &&
+	test "$(git diff-files --name-status top)" = ""
 '
 
 test_expect_success SYMLINKS 'replace a file with a symlink' '
-- 
1.7.3.4.878.g439c7