internal_phase_migration.py

"""internal-phase migration support."""

# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.

from google_hgext import util
from mercurial import exthelper
from mercurial import localrepo
from mercurial import scmutil


eh = exthelper.exthelper()
old_name = b'internal-phase'

# disabled; TODO: enable in a subsequent release
# from mercurial import phases
# from mercurial import requirements
# @eh.reposetup
# def enable_internal_phase(ui, repo):
#   """Enable the internal-phase."""
#   del ui  # unused
#   if not is_fig(repo):
#     return
#   if phases.supportinternal(repo):
#     return

#   repo.requirements.add(requirements.INTERNAL_PHASE_REQUIREMENT)
#   scmutil.writereporequirements(repo)
#   assert phases.supportinternal(repo)


@eh.wrapfunction(localrepo, 'ensurerequirementsrecognized')
def check_reqs(orig, requirements_, supported):
  """Override localrepo.ensurerequirementsrecognized for compatibility.

  Make it appear as if 'internal-phase' is supported
  on later versions of Mercurial where it's been removed.

  Avoids a crash when starting up on a repo with the
  deprecated 'internal-phase' so that
  ``remove_internal_phase_requirement`` can effect
  its change.

  Args:
    orig: original function
    requirements_: same as orig
    supported: same as orig

  Returns:
    same as orig
  """
  return orig(requirements_, supported | {old_name})


@eh.reposetup
def remove_internal_phase_requirement(ui, repo):
  """Remove any internal-phase requirement.

  In 74fb1842f8b9, Mercurial renamed the requirement for enabling the internal
  phase. This change happened during Google's adoption of the feature,
  so the current codebase also expects to support the original name.
  Remove the old requirement.

  Remove this code after the internal phase work has stabilized.

  Args:
    ui: the ui
    repo: the repo

  Returns:
    nothing
  """
  if not util.is_fig(repo):
    return
  try:
    repo.requirements.remove(old_name)
  except KeyError:
    return
  try:
    scmutil.writereporequirements(repo)
  except PermissionError:
    ui.log(b'shelve', b'no permission to update repository requirements\n')
  except Exception as exc:  # pylint: disable=broad-except
    msg = f'phase migration failed to remove internal-phase ({exc!r})\n'
    bmsg = msg.encode()
    ui.warn(bmsg)
    ui.log(b'shelve', bmsg)

The latest revision reflects the implementation we've adopted.