Do not default to --no-index when given two directories.

git-diff -- a/ b/ always defaulted to --no-index, primarily
because the function is_in_index() was implemented quite
incorrectly.

Noticed by Patrick Maaß and Simon Schubert independently,
initial patch was provided by Patrick but I fixed it
differently.

Signed-off-by: Junio C Hamano <junkio@cox.net>

diff --git a/diff-lib.c b/diff-lib.c
index 5c5b05bfe32bc90484b5bd6a9c171e0f9b04fbd6..7531e20c784c44c0b5d3ecb2057638874a09ce6c 100644 (file)
--- a/diff-lib.c
+++ b/diff-lib.c
@@ -142,18 +142,34 @@ static int queue_diff(struct diff_options *o,
        }
 }
 
+/*
+ * Does the path name a blob in the working tree, or a directory
+ * in the working tree?
+ */
 static int is_in_index(const char *path)
 {
-       int len = strlen(path);
-       int pos = cache_name_pos(path, len);
-       char c;
-
-       if (pos < 0)
-               return 0;
-       if (strncmp(active_cache[pos]->name, path, len))
-               return 0;
-       c = active_cache[pos]->name[len];
-       return c == '\0' || c == '/';
+       int len, pos;
+       struct cache_entry *ce;
+
+       len = strlen(path);
+       while (path[len-1] == '/')
+               len--;
+       if (!len)
+               return 1; /* "." */
+       pos = cache_name_pos(path, len);
+       if (0 <= pos)
+               return 1;
+       pos = -1 - pos;
+       while (pos < active_nr) {
+               ce = active_cache[pos++];
+               if (ce_namelen(ce) <= len ||
+                   strncmp(ce->name, path, len) ||
+                   (ce->name[len] > '/'))
+                       break; /* path cannot be a prefix */
+               if (ce->name[len] == '/')
+                       return 1;
+       }
+       return 0;
 }
 
 static int handle_diff_files_args(struct rev_info *revs,