tests/test-bad-extension.t

extensions: also search for extension in the 'hgext3rd' package

Mercurial extensions are not meant to be normal python package/module. Yet the
lack of an official location to install them means that a lot of them actually
install as root level python package, polluting the global Python package
namespace and risking collision with more legit packages. As we recently
discovered, core python actually support namespace package. A way for multiples
distinct "distribution" to share a common top level package without fear of
installation headache. (Namespace package allow submodule installed in different
location (of the 'sys.path') to be imported properly. So we are fine as long as
extension includes a proper 'hgext3rd.__init__.py' to declare the namespace
package.)

Therefore we introduce a 'hgext3rd' namespace packages and search for extension
in it. We'll then recommend third extensions to install themselves in it.
Strictly speaking we could just get third party extensions to install in 'hgext'
as it is also a namespace package. However, this would make the integration of
formerly third party extensions in the main distribution more complicated as the third
party install would overwrite the file from the main install. Moreover, having an
explicit split between third party and core extensions seems like a good idea.

The name 'hgext3rd' have been picked because it is short and seems explicit enough.
Other alternative I could think of where:

- hgextcontrib
- hgextother
- hgextunofficial

  $ echo 'raise Exception("bit bucket overflow")' > badext.py
  $ abspathexc=`pwd`/badext.py

  $ cat >baddocext.py <<EOF
  > """
  > baddocext is bad
  > """
  > EOF
  $ abspathdoc=`pwd`/baddocext.py

  $ cat <<EOF >> $HGRCPATH
  > [extensions]
  > gpg =
  > hgext.gpg =
  > badext = $abspathexc
  > baddocext = $abspathdoc
  > badext2 =
  > EOF

  $ hg -q help help 2>&1 |grep extension
  *** failed to import extension badext from $TESTTMP/badext.py: bit bucket overflow
  *** failed to import extension badext2: No module named badext2

show traceback

  $ hg -q help help --traceback 2>&1 | egrep ' extension|^Exception|Traceback|ImportError'
  *** failed to import extension badext from $TESTTMP/badext.py: bit bucket overflow
  Traceback (most recent call last):
  Exception: bit bucket overflow
  *** failed to import extension badext2: No module named badext2
  Traceback (most recent call last):
  ImportError: No module named badext2

names of extensions failed to load can be accessed via extensions.notloaded()

  $ cat <<EOF > showbadexts.py
  > from mercurial import cmdutil, commands, extensions
  > cmdtable = {}
  > command = cmdutil.command(cmdtable)
  > @command('showbadexts', norepo=True)
  > def showbadexts(ui, *pats, **opts):
  >     ui.write('BADEXTS: %s\n' % ' '.join(sorted(extensions.notloaded())))
  > EOF
  $ hg --config extensions.badexts=showbadexts.py showbadexts 2>&1 | grep '^BADEXTS'
  BADEXTS: badext badext2

show traceback for ImportError of hgext.name if debug is set
(note that --debug option isn't applied yet when loading extensions)

  $ (hg -q help help --traceback --config ui.debug=True 2>&1) \
  > | grep -v '^ ' \
  > | egrep 'extension..[^p]|^Exception|Traceback|ImportError|not import'
  *** failed to import extension badext from $TESTTMP/badext.py: bit bucket overflow
  Traceback (most recent call last):
  Exception: bit bucket overflow
  could not import hgext.badext2 (No module named *badext2): trying badext2 (glob)
  Traceback (most recent call last):
  ImportError: No module named *badext2 (glob)
  could not import hgext3rd.badext2 (No module named badext2): trying badext2
  Traceback (most recent call last):
  ImportError: No module named badext2
  *** failed to import extension badext2: No module named badext2
  Traceback (most recent call last):
  ImportError: No module named badext2

confirm that there's no crash when an extension's documentation is bad

  $ hg help --keyword baddocext
  *** failed to import extension badext from $TESTTMP/badext.py: bit bucket overflow
  *** failed to import extension badext2: No module named badext2
  Topics:
  
   extensions Using Additional Features