tests/test-abort-checkin.t

histedit: pass 'editform' argument to 'cmdutil.getcommiteditor'

This patch passes 'editform' argument according to the format below:

  EXTENSION[.COMMAND][.ROUTE]

  - EXTENSION: name of extension
  - COMMAND: name of command, if there are two or more commands in EXTENSION
  - ROUTE: name of route, if there are two or more routes for COMMAND

In this patch:

  - 'edit', 'fold', 'mess' and 'pick' are used as COMMAND
  - ROUTE is omitted

'histedit.pick' case is very rare, but possible if:

  - target revision causes conflict at merging (= requires '--continue'), and
  - description of it is empty ('hg commit -m " "' can create such one)

In the code path for 'histedit --continue' (the last patch hunk),
'canonaction' doesn't contain the entry for 'fold', because 'fold'
action causes:

  - using temporary commit message forcibly, and
  - making 'editopt' False always (= omit editor invocation if commit
    message is specified)

  $ cat > abortcommit.py <<EOF
  > from mercurial import util
  > def hook(**args):
  >     raise util.Abort("no commits allowed")
  > def reposetup(ui, repo):
  >     repo.ui.setconfig("hooks", "pretxncommit.nocommits", hook)
  > EOF
  $ abspath=`pwd`/abortcommit.py

  $ echo "[extensions]" >> $HGRCPATH
  $ echo "mq=" >> $HGRCPATH
  $ echo "abortcommit = $abspath" >> $HGRCPATH

  $ hg init foo
  $ cd foo
  $ echo foo > foo
  $ hg add foo

mq may keep a reference to the repository so __del__ will not be
called and .hg/journal.dirstate will not be deleted:

  $ hg ci -m foo
  error: pretxncommit.nocommits hook failed: no commits allowed
  transaction abort!
  rollback completed
  abort: no commits allowed
  [255]
  $ hg ci -m foo
  error: pretxncommit.nocommits hook failed: no commits allowed
  transaction abort!
  rollback completed
  abort: no commits allowed
  [255]

  $ cd ..