view tests/test-install.t @ 25703:1a6a117d0b95

import-checker: establish modern import convention

We introduce a new convention for declaring imports and enforce it via
the import checker script.

The new convention is only active when absolute imports are used, which is
currently nowhere. Keying off "from __future__ import absolute_import" to
engage the new import convention seems like the easiest solution. It is
also beneficial for Mercurial to use this mode because it means less work
and ambiguity for the importer and potentially better performance due to
fewer stat() system calls because the importer won't look for modules in
relative paths unless explicitly asked.

Once all files are converted to use absolute import, we can refactor
this code to again only have a single import convention and we can
require use of absolute import in the style checker.

The rules for the new convention are documented in the docstring of the
added function. Tests have been added to test-module-imports.t. Some
tests are sensitive to newlines and source column position, which makes
docstring testing difficult and/or impossible.

hg debuginstall
  $ hg debuginstall
  checking encoding (ascii)...
  checking Python executable (*) (glob)
  checking Python version (2.*) (glob)
  checking Python lib (*lib*)... (glob)
  checking installed modules (*mercurial)... (glob)
  checking templates (*mercurial?templates)... (glob)
  checking commit editor...
  checking username...
  no problems detected

hg debuginstall with no username
  $ HGUSER= hg debuginstall
  checking encoding (ascii)...
  checking Python executable (*) (glob)
  checking Python version (2.*) (glob)
  checking Python lib (*lib*)... (glob)
  checking installed modules (*mercurial)... (glob)
  checking templates (*mercurial?templates)... (glob)
  checking commit editor...
  checking username...
   no username supplied
   (specify a username in your configuration file)
  1 problems detected, please check your install!
  [1]

path variables are expanded (~ is the same as $TESTTMP)
  $ mkdir tools
  $ touch tools/testeditor.exe
#if execbit
  $ chmod 755 tools/testeditor.exe
#endif
  $ hg debuginstall --config ui.editor=~/tools/testeditor.exe
  checking encoding (ascii)...
  checking Python executable (*) (glob)
  checking Python version (*) (glob)
  checking Python lib (*lib*)... (glob)
  checking installed modules (*mercurial)... (glob)
  checking templates (*mercurial?templates)... (glob)
  checking commit editor...
  checking username...
  no problems detected