Review found the first pass aliased its answer under both ends of a mapping, which is
wrong wherever two mappings share a number: the alias lands on a key belonging to another
mapping, the later write wins, and the filter and the container then disagree — the very
fault this change exists to close. Two reproduced cases: a module publishing 8080:80 beside
9090:8080 had an explicit setting silently overwritten; a module publishing 4001:80 beside
4002:80 composed both containers onto one machine port, where before it was safely refused.
Now a mapping's answer is filed once, under the end the module names in its listens — the
number the plan, the filter, the openings, the guard and the consumer all ask for — and a
key that names two mappings is refused in the same words as a setting that does.
Also: the guard assertion in the end-to-end test failed open when the resource was absent;
the plan-mirroring helper now says it stands in only where the plan does not allocate, and
the assertions it feeds are narrowed to the port under test.
jschoubben
7d6f37af54