tests/test-state-extension.t

errors: make exit codes class variables instead

Kyle pointed out to me that we can simply make the exit codes class
variables. Python provides some magic for making them accessible as
instance variables.

This also makes it easier to let subclasses of existing errors
override the exit codes by letting them simply define their own values
as class variables. That means that there's no need to pass them into
the superclass's constructor arguments, so the superclass doesn't need
to expose the them as arguments. (Making a subclass set a different
exit code for a subclass of `StorageError` was actually the goal with
my recent series.)

Differential Revision: https://phab.mercurial-scm.org/D10758

Test extension of unfinished states support.
  $ mkdir chainify
  $ cd chainify
  $ cat >> chainify.py <<EOF
  > from mercurial import cmdutil, error, extensions, exthelper, node, scmutil, state
  > from hgext import rebase
  > 
  > eh = exthelper.exthelper()
  > 
  > extsetup = eh.finalextsetup
  > cmdtable = eh.cmdtable
  > 
  > # Rebase calls addunfinished in uisetup, so we have to call it in extsetup.
  > # Ideally there'd by an 'extensions.afteruisetup()' just like
  > # 'extensions.afterloaded()' to allow nesting multiple commands.
  > @eh.extsetup
  > def _extsetup(ui):
  >     state.addunfinished(
  >         b'chainify',
  >         b'chainify.state',
  >         continueflag=True,
  >         childopnames=[b'rebase'])
  > 
  > def _node(repo, arg):
  >     return node.hex(scmutil.revsingle(repo, arg).node())
  > 
  > @eh.command(
  >     b'chainify',
  >     [(b'r', b'revs', [], b'revs to chain', b'REV'),
  >      (b'', b'continue', False, b'continue op')],
  >     b'chainify [-r REV] +',
  >     inferrepo=True)
  > def chainify(ui, repo, **opts):
  >     """Rebases r1, r2, r3, etc. into a chain."""
  >     with repo.wlock(), repo.lock():
  >         cmdstate = state.cmdstate(repo, b'chainify.state')
  >         if opts['continue']:
  >             if not cmdstate.exists():
  >                 raise error.Abort(b'no chainify in progress')
  >         else:
  >             cmdutil.checkunfinished(repo)
  >             data = {
  >                 b'tip': _node(repo, opts['revs'][0]),
  >                 b'revs': b','.join(_node(repo, r) for r in opts['revs'][1:]),
  >             }
  >             cmdstate.save(1, data)
  > 
  >         data = cmdstate.read()
  >         while data[b'revs']:
  >             tip = data[b'tip']
  >             revs = data[b'revs'].split(b',')
  >             with state.delegating(repo, b'chainify', b'rebase'):
  >                 ui.status(b'rebasing %s onto %s\n' % (revs[0][:12], tip[:12]))
  >                 if state.ischildunfinished(repo, b'chainify', b'rebase'):
  >                     rc = state.continuechild(ui, repo, b'chainify', b'rebase')
  >                 else:
  >                     rc = rebase.rebase(ui, repo, rev=[revs[0]], dest=tip)
  >                 if rc and rc != 0:
  >                     raise error.Abort(b'rebase failed (rc: %d)' % rc)
  >             data[b'tip'] = _node(repo, b'tip')
  >             data[b'revs'] = b','.join(revs[1:])
  >             cmdstate.save(1, data)
  >         cmdstate.delete()
  >         ui.status(b'done chainifying\n')
  > EOF

  $ chainifypath=`pwd`/chainify.py
  $ echo '[extensions]' >> $HGRCPATH
  $ echo "chainify = $chainifypath" >> $HGRCPATH
  $ echo "rebase =" >> $HGRCPATH

  $ cd $TESTTMP
  $ hg init a
  $ cd a
  $ echo base > base.txt
  $ hg commit -Aqm 'base commit'
  $ echo foo > file1
  $ hg commit -Aqm 'add file'
  $ hg co -q ".^"
  $ echo bar > file2
  $ hg commit -Aqm 'add other file'
  $ hg co -q ".^"
  $ echo foo2 > file1
  $ hg commit -Aqm 'add conflicting file'
  $ hg co -q ".^"
  $ hg log --graph --template '{rev} {files}'
  o  3 file1
  |
  | o  2 file2
  |/
  | o  1 file1
  |/
  @  0 base.txt
  
  $ hg chainify -r 8430cfdf77c2 -r f8596309dff8 -r a858b338b3e9
  rebasing f8596309dff8 onto 8430cfdf77c2
  rebasing 2:f8596309dff8 "add other file"
  saved backup bundle to $TESTTMP/* (glob)
  rebasing a858b338b3e9 onto 83c722183a8e
  rebasing 2:a858b338b3e9 "add conflicting file"
  merging file1
  warning: conflicts while merging file1! (edit, then use 'hg resolve --mark')
  unresolved conflicts (see 'hg resolve', then 'hg chainify --continue')
  [240]
  $ hg status --config commands.status.verbose=True
  M file1
  ? file1.orig
  # The repository is in an unfinished *chainify* state.
  
  # Unresolved merge conflicts:
  # 
  #     file1
  # 
  # To mark files as resolved:  hg resolve --mark FILE
  
  # To continue:    hg chainify --continue
  # To abort:       hg chainify --abort
  
  $ echo foo3 > file1
  $ hg resolve --mark file1
  (no more unresolved files)
  continue: hg chainify --continue
  $ hg chainify --continue
  rebasing a858b338b3e9 onto 83c722183a8e
  rebasing 2:a858b338b3e9 "add conflicting file"
  saved backup bundle to $TESTTMP/* (glob)
  done chainifying
  $ hg log --graph --template '{rev} {files}'
  o  3 file1
  |
  o  2 file2
  |
  o  1 file1
  |
  @  0 base.txt