1 files changed, 25 insertions, 2 deletions

diff --git a/editors/diff.c b/editors/diff.c
index 07594e8d8..a3ca2b660 100644
--- a/editors/diff.c
+++ b/editors/diff.c
@@ -121,6 +121,7 @@ typedef struct FILE_and_pos_t {
 struct globals {
         smallint exit_status;
         int opt_U_context;
+        const char *other_dir;
         char *label[2];
         struct stat stb[2];
 };
@@ -760,9 +761,11 @@ static int FAST_FUNC add_to_dirlist(const char *filename,
                 void *userdata, int depth UNUSED_PARAM)
 {
         struct dlist *const l = userdata;
+        const char *file = filename + l->len;
+        while (*file == '/')
+                file++;
         l->dl = xrealloc_vector(l->dl, 6, l->e);
-        /* + 1 skips "/" after dirname */
-        l->dl[l->e] = xstrdup(filename + l->len + 1);
+        l->dl[l->e] = xstrdup(file);
         l->e++;
         return TRUE;
 }
@@ -778,6 +781,25 @@ static int FAST_FUNC skip_dir(const char *filename,
                 add_to_dirlist(filename, sb, userdata, depth);
                 return SKIP;
         }
+        if (!(option_mask32 & FLAG(N))) {
+                /* -r without -N: no need to recurse into dirs
+                 * which do not exist on the "other side".
+                 * Testcase: diff -r /tmp /
+                 * (it would recurse deep into /proc without this code) */
+                struct dlist *const l = userdata;
+                filename += l->len;
+                if (filename[0]) {
+                        struct stat osb;
+                        char *othername = concat_path_file(G.other_dir, filename);
+                        int r = stat(othername, &osb);
+                        free(othername);
+                        if (r != 0 || !S_ISDIR(osb.st_mode)) {
+                                /* other dir doesn't have similarly named
+                                 * directory, don't recurse */
+                                return SKIP;
+                        }
+                }
+        }
         return TRUE;
 }
 
@@ -791,6 +813,7 @@ static void diffdir(char *p[2], const char *s_start)
                 /*list[i].s = list[i].e = 0; - memset did it */
                 /*list[i].dl = NULL; */
 
+                G.other_dir = p[1 - i];
                 /* We need to trim root directory prefix.
                  * Using list.len to specify its length,
                  * add_to_dirlist will remove it. */