[PATCH 1/3] Fix sparse checkout not removing files from index

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

When unpack_trees() nearly completes, sparse pattern is applied and
will prevent any updates (CE_UPDATE, CE_WT_REMOVE, CE_REMOVE) outside
sparse checkout area by clearing these flags.

Unfortunately CE_REMOVE also instructs write_index() to remove files from
the index. By clearing this flag, index may keep unwanted files.

This patch turns CE_REMOVE in unpack-trees.c to CE_REMOVE|CE_WT_REMOVE
and only remove files from worktree if CE_WT_REMOVE is set. CE_REMOVE
is now only meaningful to index operations and CE_WT_REMOVE to
worktree ones.

This fault made the test suite itself faulty. With this fault fixed,
two other faults are revealed :(

Reported in http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=583699

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 cache.h                              |    3 +--
 t/t1011-read-tree-sparse-checkout.sh |    9 ++++++++-
 unpack-trees.c                       |   22 ++++++++++++----------
 3 files changed, 21 insertions(+), 13 deletions(-)

diff --git a/cache.h b/cache.h
index 0d101e4..4e7bb62 100644
--- a/cache.h
+++ b/cache.h
@@ -179,8 +179,7 @@ struct cache_entry {
 #define CE_UNHASHED  (0x200000)
 #define CE_CONFLICTED (0x800000)
 
-/* Only remove in work directory, not index */
-#define CE_WT_REMOVE (0x400000)
+#define CE_WT_REMOVE (0x400000) /* remove in work directory */
 
 #define CE_UNPACKED  (0x1000000)
 
diff --git a/t/t1011-read-tree-sparse-checkout.sh b/t/t1011-read-tree-sparse-checkout.sh
index 62246db..885578a 100755
--- a/t/t1011-read-tree-sparse-checkout.sh
+++ b/t/t1011-read-tree-sparse-checkout.sh
@@ -138,7 +138,7 @@ test_expect_success 'read-tree adds to worktree, absent case' '
 	test ! -f sub/added
 '
 
-test_expect_success 'read-tree adds to worktree, dirty case' '
+test_expect_failure 'read-tree adds to worktree, dirty case' '
 	echo init.t > .git/info/sparse-checkout &&
 	git checkout -f removed &&
 	mkdir sub &&
@@ -147,4 +147,11 @@ test_expect_success 'read-tree adds to worktree, dirty case' '
 	grep -q dirty sub/added
 '
 
+test_expect_success 'read-tree --reset removes outside worktree' '
+	echo init.t > .git/info/sparse-checkout &&
+	git checkout -f top &&
+	git reset --hard removed &&
+	test -z "$(git ls-files sub/added)"
+'
+
 test_done
diff --git a/unpack-trees.c b/unpack-trees.c
index e8f03f5..f2d148c 100644
--- a/unpack-trees.c
+++ b/unpack-trees.c
@@ -53,6 +53,9 @@ static void add_entry(struct unpack_trees_options *o, struct cache_entry *ce,
 
 	clear |= CE_HASHED | CE_UNHASHED;
 
+	if (set & CE_REMOVE)
+		set |= CE_WT_REMOVE;
+
 	memcpy(new, ce, size);
 	new->next = NULL;
 	new->ce_flags = (new->ce_flags & ~clear) | set;
@@ -84,7 +87,7 @@ static int check_updates(struct unpack_trees_options *o)
 	if (o->update && o->verbose_update) {
 		for (total = cnt = 0; cnt < index->cache_nr; cnt++) {
 			struct cache_entry *ce = index->cache[cnt];
-			if (ce->ce_flags & (CE_UPDATE | CE_REMOVE | CE_WT_REMOVE))
+			if (ce->ce_flags & (CE_UPDATE | CE_WT_REMOVE))
 				total++;
 		}
 
@@ -104,12 +107,6 @@ static int check_updates(struct unpack_trees_options *o)
 				unlink_entry(ce);
 			continue;
 		}
-
-		if (ce->ce_flags & CE_REMOVE) {
-			display_progress(progress, ++cnt);
-			if (o->update)
-				unlink_entry(ce);
-		}
 	}
 	remove_marked_cache_entries(&o->result);
 	remove_scheduled_dirs();
@@ -799,10 +796,15 @@ int unpack_trees(unsigned len, struct tree_desc *t, struct unpack_trees_options
 			/*
 			 * Merge strategies may set CE_UPDATE|CE_REMOVE outside checkout
 			 * area as a result of ce_skip_worktree() shortcuts in
-			 * verify_absent() and verify_uptodate(). Clear them.
+			 * verify_absent() and verify_uptodate().
+			 * Make sure they don't modify worktree.
 			 */
-			if (ce_skip_worktree(ce))
-				ce->ce_flags &= ~(CE_UPDATE | CE_REMOVE);
+			if (ce_skip_worktree(ce)) {
+				ce->ce_flags &= ~CE_UPDATE;
+
+				if (ce->ce_flags & CE_REMOVE)
+					ce->ce_flags &= ~CE_WT_REMOVE;
+			}
 			else
 				empty_worktree = 0;
 
-- 
1.7.1.rc1.69.g24c2f7