tests/test-ssh-repoerror.t

abort: added logic for of hg abort

This is part of `GSoC19` project `Implement abort and
continue commands`. This patch is part of the `abort plan`.

This adds the basic logic for `hg abort`. This command
aborts an multistep operation like graft, histedit, rebase,
merge and unshelve if they are in an unfinished state.

The first part of the logic is determining the unfinished
operation from the state detection API under `statemod`.
This API is extended to support `hg abort` by adding a method
to register the abort logic as a function (here `abortfunc`).

Once the unfinished operation is determined the registered
logic is used to abort the command. The benefit of this kind
of framework is that any new extension developed can support
`hg abort` by registering the command and logic under
statedetection API.

`hg abort` currently supports `--dry-run/-n` flag only.
It is used to dry run `hg abort`

Further patches sequentially add support for `graft`, `rebase`,
`unshelve`, `histedit` and `merge`.

Differential Revision: https://phab.mercurial-scm.org/D6566

#require unix-permissions no-root

initial setup

  $ cat << EOF >> $HGRCPATH
  > [ui]
  > ssh="$PYTHON" "$TESTDIR/dummyssh"
  > EOF

repository itself is non-readable
---------------------------------

  $ hg init no-read
  $ hg id ssh://user@dummy/no-read
  000000000000
  $ chmod a-rx no-read

  $ hg id ssh://user@dummy/no-read
  remote: abort: Permission denied: *$TESTTMP/no-read/.hg* (glob)
  abort: no suitable response from remote hg!
  [255]

special case files are visible, but unreadable
----------------------------------------------

This is "similar" to the test above, but the directory is "traversable". This
seems an unexpected case in real life, but we test it anyway.

  $ hg init other
  $ hg id ssh://user@dummy/other
  000000000000
  $ for item in `find other | sort -r` ; do
  >     chmod a-r $item
  > done

  $ hg id ssh://user@dummy/other
  remote: abort: Permission denied: '$TESTTMP/other/.hg/requires'
  abort: no suitable response from remote hg!
  [255]

directory toward the repository is read only
--------------------------------------------

  $ mkdir deep
  $ hg init deep/nested

  $ hg id ssh://user@dummy/deep/nested
  000000000000

  $ chmod a-rx deep

  $ hg id ssh://user@dummy/deep/nested
  remote: abort: Permission denied: *$TESTTMP/deep/nested/.hg* (glob)
  abort: no suitable response from remote hg!
  [255]

repository has wrong requirement
--------------------------------

  $ hg init repo-future
  $ hg id ssh://user@dummy/repo-future
  000000000000
  $ echo flying-car >> repo-future/.hg/requires
  $ hg id ssh://user@dummy/repo-future
  remote: abort: repository requires features unknown to this Mercurial: flying-car!
  remote: (see https://mercurial-scm.org/wiki/MissingRequirement for more information)
  abort: no suitable response from remote hg!
  [255]