Sorry for being unclear here. I don't think (honestly I don't remember,
it's been almost a month) that I meant to you should use the skipList.

Looking at that code again we use object_on_skiplist() to do an early
punt in report(), but also fsck_blob(), presumably you never want the
latter, and that early punting wouldn't be needed if your report()
function intercepted the modules blob id for stashing it away / later
reporting / whatever.

So yeah, I'm 99% sure now that's not what I meant :)

What I meant with:

    Or if we want to keep the "print <list> | process"[...]

Is that we have an existing ad-hoc IPC model for these commands in
passing along the skipList, which is made more complex because sometimes
the initial process reads the file, sometimes it passes it along as-is
to the child.

And then there's this patch that passes OIDs too, but through a
different mechanism.

I was suggesting that perhaps it made more sense to refactor both so
they could use the same mechanism, because we're potentially passing two
lists of OIDs between the two. Just one goes via line-at-a-time in the
output, the other via a config option on the command-line.

Thanks for your explanation. I still think that they are quite different
- skiplist is a user-written file containing a list of OIDs that will
likely never change, whereas my list of dangling .gitmodules is a list
of OIDs dynamically generated (and thus, always different) whenever a
fetch is done. So I think it's quite reasonable to pass skiplist as a
file name, and my list should be passed line-by-line.