Eric Sunshine [off-list ref] writes:
I had the same concern that it didn't necessarily make sense to allow
"-" for $2, but eventually thought of a case such as:
sed '...' actual | test_cmp expect - &&
which massages 'actual' before test_cmp() sees it. True, we don't
actually have such callers, but it theoretically is legitimate.
Yup, that looks a bit too stretching [*] to me, but that was what I
had in mind when I said "I'll let it pass".
Side note. Presumably that 'actual' was written by Git, to
avoid losing its exit code, e.g.
git frotz >actual &&
sed '...' actual | test_cmp expect -
but then it becomes more natural to write the second one like
so:
git frotz >raw &&
sed '...' raw >actual &&
test_cmp expect actual