view tests/test-issue2137.t @ 19933:621a26eb3a99

demandimport: allow extensions to import own modules by absolute name

Before this patch, python modules of each extensions can't import
another one in own extension by absolute name, because root modules of
each extensions are loaded with "hgext_" prefix.

For example, "import extroot.bar" in "extroot/foo.py" of "extroot"
extension fails, even though "import bar" in it succeeds.

Installing extensions into site-packages of python library path can
avoid this problem, but this solution is not reasonable in some cases:
using binary package of Mercurial on Windows, for example.

This patch retries to import with "hgext_" prefix after ImportError,
if the module in the extension may try to import another one in own
extension.

This patch doesn't change some "_import()"/"_origimport()" invocations
below, because ordinary extensions shouldn't cause such invocations.

    - invocation of "_import()" when root module imports sub-module by
      absolute path without "fromlist"

      for example, "import a.b" in "a.__init__.py".

      extensions are loaded with "hgext_" prefix, and this causes
      execution of another (= fixed by this patch) code path.

    - invocation of "_origimport()" when "level != -1" with "fromlist"

      for example, importing after "from __future__ import
      absolute_import" (level == 0), or "from . import b" or "from .a
      import b" (0 < level),

      for portability between python versions and environments,
      extensions shouldn't cause "level != -1".

http://mercurial.selenic.com/bts/issue2137

Setup:

create a little extension that has 3 side-effects:
1) ensure changelog data is not inlined
2) make revlog to use lazyparser
3) test that repo.lookup() works
1 and 2 are preconditions for the bug; 3 is the bug.

  $ cat > commitwrapper.py <<EOF
  > from mercurial import extensions, node, revlog
  > 
  > def reposetup(ui, repo):
  >     class wraprepo(repo.__class__):
  >         def commit(self, *args, **kwargs):
  >             result = super(wraprepo, self).commit(*args, **kwargs)
  >             tip1 = node.short(repo.changelog.tip())
  >             tip2 = node.short(repo.lookup(tip1))
  >             assert tip1 == tip2
  >             ui.write('new tip: %s\n' % tip1)
  >             return result
  >     repo.__class__ = wraprepo
  > 
  > def extsetup(ui):
  >     revlog._maxinline = 8             # split out 00changelog.d early
  >     revlog._prereadsize = 8           # use revlog.lazyparser
  > EOF

  $ cat >> $HGRCPATH <<EOF
  > [extensions]
  > commitwrapper = `pwd`/commitwrapper.py
  > EOF

  $ hg init repo1
  $ cd repo1
  $ echo a > a
  $ hg commit -A -m'add a with a long commit message to make the changelog a bit bigger'
  adding a
  new tip: 553596fad57b

Test that new changesets are visible to repo.lookup():

  $ echo a >> a
  $ hg commit -m'one more commit to demonstrate the bug'
  new tip: 799ae3599e0e

  $ hg tip
  changeset:   1:799ae3599e0e
  tag:         tip
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     one more commit to demonstrate the bug
  

  $ cd ..