wireproto: only expose "clonebundles" to version 1 transports This may make a comeback in wire protocol version 2. The feature definitely needs to be carried forward. But at this juncture, I'm flirting with the idea of implementing this via a "redirect" mechanism at the command response level itself rather than something that requires one-off client support for querying and handling. i.e. I want to make it so servers can say "fetch this first and then come back" and clients handle that automatically. This would not only support clone bundles, but would also support piece-meal "pull bundles." Whatever happens, we can deal with it down the road. Differential Revision: https://phab.mercurial-scm.org/D3203

wireproto: define and expose types of wire command arguments Exposing the set of argument names is cool. But with wire protocol version 2, we're using CBOR to transport arguments and this allows us to have typing for arguments. Typed arguments are much nicer because they will cut down on transfer overhead and processing overhead for decoding values. This commit teaches @wireprotocommand to accept a dictionary for arguments. The arguments registered for version 2 transports are canonically stored as dictionaries rather than a space-delimited string. It is an error to defined arguments with a dictionary for commands using version 1 transports. This reinforces my intent to fully decouple command handlers for version 2 transports. Differential Revision: https://phab.mercurial-scm.org/D3202

wireproto: only expose "stream_out" to version 1 transports I have plans to implement stream clone using a better mechanism than this existing command. Let's not carry it forward to wire protocol version 2. Differential Revision: https://phab.mercurial-scm.org/D3201

wireproto: implement capabilities for wire protocol v2 The capabilities mechanism for wire protocol version 2 represents a clean break from version 1. Instead of effectively exchanging a set of capabilities, we're exchanging a rich data structure. This data structure currently contains information about every available command, including its accepted arguments. It also contains information about supported compression formats. Exposing information about supported commands will allow clients to automatically generate bindings to the server. Clients will be able to do things like detect when they are attempting to run a command that isn't known to the server. Exposing the required permissions to run a command can be used by clients to determine if they have privileges to call a command before actually calling it. We could potentially even have clients send credentials preemptively without waiting for the server to deny the command request. Lots of potential here. The data returned by this command will likely evolve heavily. So we shouldn't bikeshed the implementation just yet. Differential Revision: https://phab.mercurial-scm.org/D3200

context: add deprecation warnings for deprecated types of changeids It's close to code freeze, and dropping support for repo['123'] and repo ['my-bookmark'] and repo['deadbeef'] is pretty dispruptive, so this just adds deprecation warnings so extensions can easily find the places they need to fix. Differential Revision: https://phab.mercurial-scm.org/D3197

revsymbol: stop delegating to repo.__getitem__ for unhandled symbols (API) The only remaining cases where we were delegating unhandled symbols to repo.__getitem__ should now be when the symbol could not be found. In that case we just delegated to repo.__getitem__ for the error message. Let's just copy the error message instead. If there were any cases where we got e.g. a binary nodeid or an integer revnum into revsymbol() (e.g. via repo.lookup()), we'd now start raising an exception instead. That is why this is marked (API). This affects one test case, but the new behavior seems better to me. I can't tell if the old behavior was desired or if the test was just there to document how it happened to work. Differential Revision: https://phab.mercurial-scm.org/D3196

context: handle partial nodeids in revsymbol() Similar reasoning as previous patches. Differential Revision: https://phab.mercurial-scm.org/D3195