[PATCH] get_relative_cwd(): clarify why it handles dir == NULL
The comment did not make a good case why it makes sense. It does so now.
Pointed out by Junio Hamano.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
---
dir.c | 11 ++++++++++-
1 files changed, 10 insertions(+), 1 deletions(-)
diff --git a/dir.c b/dir.c
index b3329f4..791c566 100644
--- a/dir.c
+++ b/dir.c
@@ -646,7 +646,16 @@ file_exists(const char *f)
/*
* get_relative_cwd() gets the prefix of the current working directory
* relative to 'dir'. If we are not inside 'dir', it returns NULL.
- * As a convenience, it also returns NULL if 'dir' is already NULL.
+ *
+ * As a convenience, it also returns NULL if 'dir' is already NULL. The
+ * reason for this behaviour is that it is natural for functions returning
+ * directory names to return NULL to say "this directory does not exist"
+ * or "this directory is invalid". These cases are usually handled the
+ * same as if the cwd is not inside 'dir' at all, so get_relative_cwd()
+ * returns NULL for both of them.
+ *
+ * Most notably, get_relative_cwd(buffer, size, get_git_work_tree())
+ * unifies the handling of "outside work tree" with "no work tree at all".
*/
char *get_relative_cwd(char *buffer, int size, const char *dir)
{
--
1.5.3.rc3.112.gf60b6
Johannes Schindelin <johannes.schindelin@gmx.de>