tests/test-empty.t

setup: properly package distutils in py2exe virtualenv builds

Our in-repo py2exe packaging code uses virtualenvs for managing
dependencies. An advantage of this is that packaging is more
deterministic and reproducible. Without virtualenvs, we need to
install packages in the system Python install. Packages installed
by other consumers of the system Python could leak into the Mercurial
package.

A regression from this change was that py2exe packages contained
the virtualenv's hacked distutils modules instead of the original
distutils modules. (virtualenv installs a hacked distutils module
because distutils uses relative path lookups that fail when running
from a virtualenv.)

This commit introduces a workaround so py2exe packaging uses the
original distutils modules when running from a virtualenv.

With this change, `import distutils` no longer fails from py2exe
builds produced from a virtualenv. This fixes the regression.
Furthermore, we now include all distutils modules. Before, py2exe's
module finding would only find modules there were explicitly
referenced in code. So, we now package a complete copy of distutils
instead of a partial one. This is even better than before.

# no-check-commit foo_bar function name

Create an empty repo:

  $ hg init a
  $ cd a

Try some commands:

  $ hg log
  $ hg grep wah
  [1]
  $ hg manifest
  $ hg verify
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  checked 0 changesets with 0 changes to 0 files

Check the basic files created:

  $ ls .hg
  00changelog.i
  cache
  requires
  store
  wcache

Should be empty:

  $ ls .hg/store

Poke at a clone:

  $ cd ..
  $ hg clone a b
  updating to branch default
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ cd b
  $ hg verify
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  checked 0 changesets with 0 changes to 0 files
  $ ls .hg
  00changelog.i
  hgrc
  requires
  store

Should be empty:

  $ ls .hg/store

  $ cd ..