tests/test-abort-checkin.t

url: avoid re-issuing incorrect password (issue3210)

Some draconian IT setups lock accounts after a small number of incorrect
password attempts. Mercurial's implementation of the urllib2 authentication was
causing 5 retry attempts with the same credentials, without prompting the user.
The code was attempting to check whether the authorization token had changed,
but unfortunately was reading the misleading 'headers' member of the request
instead of using the 'get_header' accessor.

Modelled on fix for Python issue 8797:
https://bugs.python.org/issue8797
https://hg.python.org/cpython/rev/30e8a8f22a2a

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

  $ cat <<EOF >> $HGRCPATH
  > [extensions]
  > mq =
  > abortcommit = $abspath
  > EOF

  $ 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 ..