discovery: test coverage for issue4438 / 86c35b7ae300 / 73cfaa348650 The randomness in the discovery protocol made this problem hard to reproduce. The test mocks random.sample to make sure we hit the problem every time. The set iteration order also made the output unstable ... but with the issue fixed, it is stable.

hgweb: fix a crash when using web.archivesubrepos A matcher is required when enabling the subrepo option on archival.archive(), because that calls match.narrowmatcher(), which accesses fields on the object. It's therefore probably a bad idea to default the matcher to None on archive(), but that's a fix for default.

tests: introduce a subrepository to test-archive.t This will be used in an upcoming patch to add coverage for web.archivesubrepos.