[PATCH/RFC] sane_execvp(): ignore non-directory on PATH

From: Junio C Hamano <gitster@pobox.com>
Date: Jul 31, 2012, 19:46 UTC
Message-ID: <7vobmviuii.fsf@alter.siamese.dyndns.org>

When you have a non-directory on your PATH, a funny thing happens:

	$ PATH=$PATH:/bin/sh git foo
	fatal: cannot exec 'git-foo': Not a directory?

Worse yet, as real commands always take precedence over aliases, this behaviour interacts rather badly with them:

	$ PATH=$PATH:/bin/sh git -c alias.foo=show git foo -s
	fatal: cannot exec 'git-foo': Not a directory?

This is because an ENOTDIR error from the underlying execvp(2) is reported back to the caller of our sane_execvp() wrapper as-is. By translating it to ENOENT, just like the case where we _might_ have the command in an unreadable directory, fixes it. Without an alias, we would get

	git: 'foo' is not a git command. See 'git --help'.

and we use the 'foo' alias when it is available.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
---

 * We can view this as a follow-up to 38f865c (run-command: treat
   inaccessible directories as ENOENT, 2012-03-30).

 run-command.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/run-command.c b/run-command.c
index 805d41f..f9b7db2 100644
--- a/run-command.c
+++ b/run-command.c
@@ -77,6 +77,8 @@ int sane_execvp(const char *file, char * const argv[])
 	 */
 	if (errno == EACCES && !strchr(file, '/'))
 		errno = exists_in_PATH(file) ? EACCES : ENOENT;
+	else if (errno == ENOTDIR && !strchr(file, '/'))
+		errno = ENOENT;
 	return -1;
 }