[PATCH] builtin-apply: check for empty files when detecting creation patch

[Imre Deak <imre.deak@gmail.com>]

When we can only guess if we have a creation patch, we do
this by treating the patch as such if there weren't any old
lines. Zero length files can be patched without old lines
though, so do an extra check for file size.

Signed-off-by: Imre Deak <imre.deak@gmail.com>
---
 builtin-apply.c |   34 +++++++++++++++++++++++++++++++++-
 1 files changed, 33 insertions(+), 1 deletions(-)

diff --git a/builtin-apply.c b/builtin-apply.c
index caa3f2a..80d0779 100644
--- a/builtin-apply.c
+++ b/builtin-apply.c
@@ -1096,6 +1096,33 @@ static int parse_fragment(char *line, unsigned long size,
 	return offset;
 }
 
+static size_t existing_file_size(const char *file)
+{
+	size_t st_size = -1;
+
+	if (file == NULL)
+		return -1;
+
+	if (cached) {
+		struct cache_entry *ce;
+		int pos;
+
+		pos = cache_name_pos(file, strlen(file));
+		if (pos < 0)
+			return -1;
+		ce = active_cache[pos];
+		st_size = ntohl(ce->ce_size);
+	} else {
+		struct stat st;
+
+		if (lstat(file, &st) < 0)
+			return -1;
+		st_size = st.st_size;
+	}
+
+	return st_size;
+}
+
 static int parse_single_patch(char *line, unsigned long size, struct patch *patch)
 {
 	unsigned long offset = 0;
@@ -1143,13 +1170,18 @@ static int parse_single_patch(char *line, unsigned long size, struct patch *patc
 	if (patch->is_delete < 0 &&
 	    (newlines || (patch->fragments && patch->fragments->next)))
 		patch->is_delete = 0;
+	/* FIXME: How can be there context if it's a creation / deletion? */
 	if (!unidiff_zero || context) {
 		/* If the user says the patch is not generated with
 		 * --unified=0, or if we have seen context lines,
 		 * then not having oldlines means the patch is creation,
 		 * and not having newlines means the patch is deletion.
+		 *
+		 * It's also possible that a zero length file is added
+		 * to.
 		 */
-		if (patch->is_new < 0 && !oldlines) {
+		if (patch->is_new < 0 && !oldlines &&
+		    existing_file_size(patch->old_name) != 0) {
 			patch->is_new = 1;
 			patch->old_name = NULL;
 		}
-- 
1.5.4.2.dirty