get_cwd_relative(): do not misinterpret root path

Commit 490544b (get_cwd_relative(): do not misinterpret suffix as
subdirectory) handles case where:

dir = "/path/work";
cwd = "/path/work-xyz";

When it comes to the end of get_cwd_relative(), dir is at '\0' and cwd
is at '-'. The rest of cwd, "-xyz", clearly cannot be the relative
path from dir to cwd. However there is another case where:

dir = "/";          /* or even "c:/" */
cwd = "/path/to/here";

In this special case, while *cwd == 'p', which is not a path
separator, the rest of cwd, "path/to/here", can be returned as a
relative path from dir to cwd.

Handle this case and make t1509 pass again.

Reported-by: Albert Strasheim <fullung@gmail.com>
Reported-by: Matthijs Kooijman <matthijs@stdin.nl>
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/dir.c b/dir.c
index 7f912c76f268e2f27857a67d565e77be0e43660d..ee9299db0536e14a6fdb78f3f5a25ea62aaf6075 100644 (file)
--- a/dir.c
+++ b/dir.c
@@ -964,6 +964,12 @@ char *get_relative_cwd(char *buffer, int size, const char *dir)
        case '/':
                return cwd + 1;
        default:
+               /*
+                * dir can end with a path separator when it's root
+                * directory. Return proper prefix in that case.
+                */
+               if (dir[-1] == '/')
+                       return cwd;
                return NULL;
        }
 }