tests/test-wireproto-command-listkeys.t

copies: add config option for writing copy metadata to file and/or changset

This introduces a config option that lets you choose to write copy
metadata to the changeset extras instead of to filelog. There's also
an option to write it to both places. I imagine that may possibly be
useful when transitioning an existing repo.

The copy metadata is stored as two fields in extras: one for copies
since p1 and one for copies since p2.

I may need to add more information later in order to make copy tracing
faster. Specifically, I'm thinking out recording which files were
added or removed so that copies._chaincopies() doesn't have to look at
the manifest for that. But that would just be an optimization and that
can be added once we know if it's necessary.

I have also considered saving space by using replacing the destination
file path by an index into the "files" list, but that can also be
changed later (but before the feature is ready to release).

Differential Revision: https://phab.mercurial-scm.org/D6183

  $ . $TESTDIR/wireprotohelpers.sh

  $ hg init server
  $ enablehttpv2 server
  $ cd server
  $ hg debugdrawdag << EOF
  > C D
  > |/
  > B
  > |
  > A
  > EOF

  $ hg phase --public -r C
  $ hg book -r C @

  $ hg log -T '{rev}:{node} {desc}\n'
  3:be0ef73c17ade3fc89dc41701eb9fc3a91b58282 D
  2:26805aba1e600a82e93661149f2313866a221a7b C
  1:112478962961147124edd43549aedd1a335e44bf B
  0:426bada5c67598ca65036d57d9e4b64b0c1ce7a0 A

  $ hg serve -p $HGPORT -d --pid-file hg.pid -E error.log
  $ cat hg.pid > $DAEMON_PIDS

Request for namespaces works

  $ sendhttpv2peer << EOF
  > command listkeys
  >     namespace namespaces
  > EOF
  creating http peer for wire protocol version 2
  sending listkeys command
  response: {
    b'bookmarks': b'',
    b'namespaces': b'',
    b'phases': b''
  }

Request for phases works

  $ sendhttpv2peer << EOF
  > command listkeys
  >     namespace phases
  > EOF
  creating http peer for wire protocol version 2
  sending listkeys command
  response: {
    b'be0ef73c17ade3fc89dc41701eb9fc3a91b58282': b'1',
    b'publishing': b'True'
  }

Request for bookmarks works

  $ sendhttpv2peer << EOF
  > command listkeys
  >     namespace bookmarks
  > EOF
  creating http peer for wire protocol version 2
  sending listkeys command
  response: {
    b'@': b'26805aba1e600a82e93661149f2313866a221a7b'
  }

  $ cat error.log