view tests/test-custom-filters.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".

  $ hg init

  $ cat > .hg/hgrc <<EOF
  > [extensions]
  > prefixfilter = prefix.py
  > [encode]
  > *.txt = stripprefix: Copyright 2046, The Masters
  > [decode]
  > *.txt = insertprefix: Copyright 2046, The Masters
  > EOF

  $ cat > prefix.py <<EOF
  > from mercurial import util
  > def stripprefix(s, cmd, filename, **kwargs):
  >     header = '%s\n' % cmd
  >     if s[:len(header)] != header:
  >         raise util.Abort('missing header "%s" in %s' % (cmd, filename))
  >     return s[len(header):]
  > def insertprefix(s, cmd):
  >     return '%s\n%s' % (cmd, s)
  > def reposetup(ui, repo):
  >     repo.adddatafilter('stripprefix:', stripprefix)
  >     repo.adddatafilter('insertprefix:', insertprefix)
  > EOF

  $ cat > .hgignore <<EOF
  > .hgignore
  > prefix.py
  > prefix.pyc
  > EOF

  $ cat > stuff.txt <<EOF
  > Copyright 2046, The Masters
  > Some stuff to ponder very carefully.
  > EOF
  $ hg add stuff.txt
  $ hg ci -m stuff

Repository data:

  $ hg cat stuff.txt
  Some stuff to ponder very carefully.

Fresh checkout:

  $ rm stuff.txt
  $ hg up -C
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ cat stuff.txt
  Copyright 2046, The Masters
  Some stuff to ponder very carefully.
  $ echo "Very very carefully." >> stuff.txt
  $ hg stat
  M stuff.txt

  $ echo "Unauthorized material subject to destruction." > morestuff.txt

Problem encoding:

  $ hg add morestuff.txt
  $ hg ci -m morestuff
  abort: missing header "Copyright 2046, The Masters" in morestuff.txt
  [255]
  $ hg stat
  M stuff.txt
  A morestuff.txt