The check that skips copying a base the mesh already holds asked with no Accept header, and a
registry answers a manifest only in a media type the caller named: the same digest answered 200 with
the manifest types and 404 without them. So the builder concluded it held nothing, copied every
vendor base again, and exhausted the public hub's pull limit a second time today.
The test could not have caught it, because the fake registry answered a manifest HEAD regardless of
Accept — more permissive than the thing it stands in for. It is now as strict as a real registry, and
fails without the fix.
jschoubben
338d033632