Make git-rev-list and git-rev-parse argument parsing stricter

[Linus Torvalds <torvalds@osdl.org>]

If you pass it a filename without the "--" marker to separate it from
revision information and flags, we now require that the file in question
actually exists. This makes mis-typed revision information not be silently
just considered a strange filename.

With the "--" marker, you can continue to pass in filenames that do not
actually exists - useful for querying what happened to a file that you
no longer have in the repository.

[ All scripts should use the "--" format regardless, to make things
  unambiguous. So this change should not affect any existing tools ]

Signed-off-by: Linus Torvalds <torvalds@osdl.org>
----

I hit this the hard way when I was showing off git at Linux.Conf.Au 
yesterday, and I asked for

	git log v2.6.14..v2.6.16

which silently did nothing at all. The reason? I don't actually have a 
v2.6.16, the most recent version is 2.6.16-rc1. So it thought 
v2.6.14..v2.6.16 was a _filename_.

Now, normally, if you use the "proper" format (with the -- delimeter to 
mark where filenames start), you'd never have this ambiguity. But without 
the "--", the way I decided that we should disambiguate things is to 
verify that any filename given with the ambiguous shorthand version 
actually exists.

Comments?

diff --git a/rev-list.c b/rev-list.c
index d060966..e00e6fc 100644
--- a/rev-list.c
+++ b/rev-list.c
@@ -844,8 +844,12 @@ int main(int argc, const char **argv)
 			arg++;
 			limited = 1;
 		}
-		if (get_sha1(arg, sha1) < 0)
+		if (get_sha1(arg, sha1) < 0) {
+			struct stat st;
+			if (lstat(arg, &st) < 0)
+				die("'%s': %s", arg, strerror(errno));
 			break;
+		}
 		commit = get_commit_reference(arg, sha1, flags);
 		handle_one_commit(commit, &list);
 	}
diff --git a/rev-parse.c b/rev-parse.c
index 0c951af..7abad35 100644
--- a/rev-parse.c
+++ b/rev-parse.c
@@ -154,6 +154,7 @@ int main(int argc, char **argv)
 	const char *prefix = setup_git_directory();
 	
 	for (i = 1; i < argc; i++) {
+		struct stat st;
 		char *arg = argv[i];
 		char *dotdot;
 	
@@ -293,6 +294,8 @@ int main(int argc, char **argv)
 		}
 		if (verify)
 			die("Needed a single revision");
+		if (lstat(arg, &st) < 0)
+			die("'%s': %s", arg, strerror(errno));
 		as_is = 1;
 		show_file(arg);
 	}