On Mon, Oct 23, 2023 at 02:58:42PM -0400, Jeff King wrote:

On Mon, Oct 23, 2023 at 11:19:13AM +0200, Patrick Steinhardt wrote:

quoted

quoted

+	case SOURCE_INCORE:
+		assert(source->read <= source->size);

Is there any guideline around when to use `assert()` vs `BUG()`? I think
that this assertion here is quite critical, because when it does not
hold we can end up performing out-of-bounds reads and writes. But as
asserts are typically missing in non-debug builds, this safeguard would
not do anything for our end users, right?

I don't think we have a written guideline. My philosophy is: always use
BUG(), because you will never be surprised that the assertion was not
compiled in (and I think compiling without assertions is almost
certainly premature optimization, especially given the way we tend to
use them).

-Peff

I'm inclined to agree with your philosophy. Makes me wonder whether we
should write a Coccinelle rule to catch this. But a quick-and-dirty grep
in our codebase shows that such a rule would cause quite a lot of churn:

$ git grep BUG\( | wc -l
677
$ git grep assert\( | wc -l
549

Probably not worth it.

Patrick