fast-export: Fix output order of D/F changes

The fast-import stream format requires incremental changes which take place
immediately, meaning that for D->F conversions all files below the relevant
directory must be deleted before the resulting file of the same name is
created.  Reversing the order can result in fast-import silently deleting
the file right after creating it, resulting in the file missing from the
resulting repository.

We correct this by first sorting the diff_queue_struct in depth-first
order.

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/builtin/fast-export.c b/builtin/fast-export.c
index c6dd71a..965e90e 100644 (file)
--- a/builtin/fast-export.c
+++ b/builtin/fast-export.c
@@ -147,10 +147,39 @@ static void handle_object(const unsigned char *sha1)
        free(buf);
 }
 
+static int depth_first(const void *a_, const void *b_)
+{
+       const struct diff_filepair *a = *((const struct diff_filepair **)a_);
+       const struct diff_filepair *b = *((const struct diff_filepair **)b_);
+       const char *name_a, *name_b;
+       int len_a, len_b, len;
+       int cmp;
+
+       name_a = a->one ? a->one->path : a->two->path;
+       name_b = b->one ? b->one->path : b->two->path;
+
+       len_a = strlen(name_a);
+       len_b = strlen(name_b);
+       len = (len_a < len_b) ? len_a : len_b;
+
+       /* strcmp will sort 'd' before 'd/e', we want 'd/e' before 'd' */
+       cmp = memcmp(name_a, name_b, len);
+       if (cmp)
+               return cmp;
+       return (len_b - len_a);
+}
+
 static void show_filemodify(struct diff_queue_struct *q,
                            struct diff_options *options, void *data)
 {
        int i;
+
+       /*
+        * Handle files below a directory first, in case they are all deleted
+        * and the directory changes to a file or symlink.
+        */
+       qsort(q->queue, q->nr, sizeof(q->queue[0]), depth_first);
+
        for (i = 0; i < q->nr; i++) {
                struct diff_filespec *ospec = q->queue[i]->one;
                struct diff_filespec *spec = q->queue[i]->two;

diff --git a/t/t9350-fast-export.sh b/t/t9350-fast-export.sh
index 69179c6..1ee1461 100755 (executable)
--- a/t/t9350-fast-export.sh
+++ b/t/t9350-fast-export.sh
@@ -376,7 +376,7 @@ 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_failure 'directory becomes symlink'        '
+test_expect_success 'directory becomes symlink'        '
        git init dirtosymlink &&
        git init result &&
        (