tests/test-wireproto-command-heads.t

mergestate: introduce a new ACTION_KEEP_NEW

`ACTION_KEEP` is overloaded and it's hard to figure out how we end up with this
KEEP, what was the state of things.

In a previous patch, we introduced `ACTION_KEEP_ABSENT` which represents files
which are kept absent in the working directory.

There is another special case where we keep the file when it's not present on
both ancestor and remote side. We introduce a dedicated action for that.

The goal is to use these information to make bid merge smarter.

Differential Revision: https://phab.mercurial-scm.org/D9002

  $ . $TESTDIR/wireprotohelpers.sh

  $ hg init server
  $ enablehttpv2 server
  $ cd server
  $ hg debugdrawdag << EOF
  > H I J
  > | | |
  > E F G
  > | |/
  > C D
  > |/
  > B
  > |
  > A
  > EOF

  $ hg phase --force --secret J
  $ hg phase --public E

  $ hg log -r 'E + H + I + G + J' -T '{rev}:{node} {desc} {phase}\n'
  4:78d2dca436b2f5b188ac267e29b81e07266d38fc E public
  7:ae492e36b0c8339ffaf328d00b85b4525de1165e H draft
  8:1d6f6b91d44aaba6d5e580bc30a9948530dbe00b I draft
  6:29446d2dc5419c5f97447a8bc062e4cc328bf241 G draft
  9:dec04b246d7cbb670c6689806c05ad17c835284e J secret

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

All non-secret heads returned by default

  $ sendhttpv2peer << EOF
  > command heads
  > EOF
  creating http peer for wire protocol version 2
  sending heads command
  response: [
    b'\x1dok\x91\xd4J\xab\xa6\xd5\xe5\x80\xbc0\xa9\x94\x850\xdb\xe0\x0b',
    b'\xaeI.6\xb0\xc83\x9f\xfa\xf3(\xd0\x0b\x85\xb4R]\xe1\x16^',
    b')Dm-\xc5A\x9c_\x97Dz\x8b\xc0b\xe4\xcc2\x8b\xf2A'
  ]

Requesting just the public heads works

  $ sendhttpv2peer << EOF
  > command heads
  >     publiconly 1
  > EOF
  creating http peer for wire protocol version 2
  sending heads command
  response: [
    b'x\xd2\xdc\xa46\xb2\xf5\xb1\x88\xac&~)\xb8\x1e\x07&m8\xfc'
  ]

  $ cat error.log