wireprotoserver: handle SSH protocol version 2 upgrade requests This commit teaches the SSH server to recognize the "upgrade" request line that clients send when they wish to switch the channel to version 2 of the SSH protocol. Servers don't honor upgrade requests unless an experimental config option is set. Since the built-in server now supports upgrade requests, our test server to test the handshake has been deleted. Existing tests use the built-in server and their output doesn't change. The upgrade is handled in our state machine. The end result is a bit wonky, as the server transitions back to version 1 state immediately after upgrading. But this will change as soon as version 2 has an actual protocol that differs from version 1. Tests demonstrating that the new server is a bit more strict about the upgrade handshake have been added. Differential Revision: https://phab.mercurial-scm.org/D2204

wireprotoserver: move SSH server operation to a standalone function The server-side processing logic will soon get a bit more complicated in order to handle protocol switches. We will use a state machine to help make the transitions clearer. To prepare for this, we move SSH server operation into a standalone function. We structure it as a very simple state machine. It only has two states for now, with one state containing the bulk of the logic. But things will evolve shortly. Differential Revision: https://phab.mercurial-scm.org/D2203

py3: stringify integer with %d instead of bytes() The unbundle wire protocol command now returns a properly formatted reply in Python 3. Differential Revision: https://phab.mercurial-scm.org/D2274

py3: add b'' to test-sshserver.py # skip-blame because adding b'' prefixes Differential Revision: https://phab.mercurial-scm.org/D2273

py3: add b'' to config options in test extension # skip-blame because just b'' prefixes Differential Revision: https://phab.mercurial-scm.org/D2272

manifest: add support for including directories outside narrowspec When using tree manifests and the client doesn't have a directory, we have two choices for what to do with "hg manifest" output: 1) ignore the directory, and 2) include the directory (not files within it). For "hg files", we decided to ignore the directories (and files) outside the narrowspec. If we choose to not include directories outside the narrowspec, then I think we should also make sure we don't include files outside the narrowspec. I also think we should add --outside-narrow flag (or other name). Thus, whichever way we go, I think we should have a way of displaying paths (files or directories) outside the narrowspec. For that we'll need to handle the 't' flag that narrowhg uses, and that's what this patch adds support for. Differential Revision: https://phab.mercurial-scm.org/D2235

narrow: restrict manifest iteration by using manifest.walk(matcher) This is only for root nodes, so it shouldn't really matter (they're rarely huge), but seems cleaner. Differential Revision: https://phab.mercurial-scm.org/D2234

narrow: only diff manifest part within narrowspec when generating changegroup Since 959ebff3505a (manifest: add match argument to diff and filesnotin, 2017-03-07), we have a more efficient way of diffing manifests while applying a matcher. Let's use that while generating narrowed changegroups, so we avoid diffing parts of the manifest that don't match the narrowspec. Differential Revision: https://phab.mercurial-scm.org/D2233