tests/test-default-push.t

ui: change default path fallback mechanism (issue4796)

The previous paths API code always fell back to the default path. This
was wrong because if a requested path doesn't exist, that should error.
Only if no path was requested should we fall back to the default.

As part of implementing the test case for issue 4796, it was discovered
that the "repository does not exist" error message raised by
localrepository.__init__ wasn't being seen because the paths API
validates paths before localrepository.__init__ was being called.
The exception and error message from localrepository.__init__ has
been introduced to getpath(). This necessitated rewriting
expandpath() both to catch the exception and to have proper
default fallback.

This code is more complicated than I'd like. But making all tests pass
was a big chore. As more code moves to getpath(), there will likely be
opportunities to improve things a bit.

  $ hg init a

  $ echo a > a/a
  $ hg --cwd a ci -Ama
  adding a

  $ hg clone a c
  updating to branch default
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved

  $ hg clone a b
  updating to branch default
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved

  $ echo b >> b/a
  $ hg --cwd b ci -mb

Push should provide a hint when both 'default' and 'default-push' not set:
  $ cd c
  $ hg push --config paths.default=
  abort: default repository not configured!
  (see the "path" section in "hg help config")
  [255]

  $ cd ..

Push should push to 'default' when 'default-push' not set:

  $ hg --cwd b push
  pushing to $TESTTMP/a (glob)
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 1 changes to 1 files

Push should push to 'default-push' when set:

  $ echo '[paths]' >> b/.hg/hgrc
  $ echo 'default-push = ../c' >> b/.hg/hgrc
  $ hg --cwd b push
  pushing to $TESTTMP/c (glob)
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 1 changes to 1 files

Pushing to a path that isn't defined should not fall back to default

  $ hg --cwd b push doesnotexist
  abort: repository doesnotexist does not exist!
  [255]