[PATCH 1/2] fast-import: Handle directories changing into symlinks

[Elijah Newren <newren@gmail.com>]

Signed-off-by: Elijah Newren <newren@gmail.com>
---
I hesitated a bit to put the testcase in t9350-fast-export.sh instead of
t9300-fast-import.sh.  However, this patch fixes a bug where
  fast-export <args> | fast-import
accidentally munges data, and t9300-fast-import.sh has no calls to
fast-export while t9350-fast-export.sh has calls to both fast-export and
fast-import.  If I should design a test for t9300-fast-import.sh instead
of (or in addition to) what I have here, let me know. 

 fast-import.c          |    5 +++++
 t/t9350-fast-export.sh |   24 ++++++++++++++++++++++++
 2 files changed, 29 insertions(+), 0 deletions(-)

diff --git a/fast-import.c b/fast-import.c
index 129a786..064348e 100644
--- a/fast-import.c
+++ b/fast-import.c
@@ -1528,6 +1528,11 @@ static int tree_content_remove(
 	for (i = 0; i < t->entry_count; i++) {
 		e = t->entries[i];
 		if (e->name->str_len == n && !strncmp(p, e->name->str_dat, n)) {
+			if (slash1 && S_ISLNK(e->versions[1].mode))
+				/* p was already removed by an earlier change
+				 * of a parent directory to a symlink.
+				 */
+				return 1;
 			if (!slash1 || !S_ISDIR(e->versions[1].mode))
 				goto del_entry;
 			if (!e->tree)
diff --git a/t/t9350-fast-export.sh b/t/t9350-fast-export.sh
index d43f37c..1ee1461 100755
--- a/t/t9350-fast-export.sh
+++ b/t/t9350-fast-export.sh
@@ -376,4 +376,28 @@ test_expect_success 'tree_tag-obj'    'git fast-export tree_tag-obj'
 test_expect_success 'tag-obj_tag'     'git fast-export tag-obj_tag'
 test_expect_success 'tag-obj_tag-obj' 'git fast-export tag-obj_tag-obj'
 
+test_expect_success 'directory becomes symlink'        '
+	git init dirtosymlink &&
+	git init result &&
+	(
+		cd dirtosymlink &&
+		mkdir foo &&
+		mkdir bar &&
+		echo hello > foo/world &&
+		echo hello > bar/world &&
+		git add foo/world bar/world &&
+		git commit -q -mone &&
+		git rm -r foo &&
+		ln -s bar foo &&
+		git add foo &&
+		git commit -q -mtwo
+	) &&
+	(
+		cd dirtosymlink &&
+		git fast-export master -- foo |
+		(cd ../result && git fast-import --quiet)
+	) &&
+	(cd result && git show master:foo)
+'
+
 test_done
-- 
1.6.6.1