From d228460676ae9834c3d89ebddc98447ba5ab411f Mon Sep 17 00:00:00 2001
From: "Mr. Senko" <atodorov@mrsenko.com>
Date: Fri, 9 Mar 2018 13:02:42 +0200
Subject: [PATCH] Let DjangoInstalledChecker warn when Django isn't available

by ignoring the import failure Python will not produce a traceback
but instead let DjangoInstalledChecker do its job and warn the user.

I also add a CI build stage to test this scenario since we don't want
to continue if this isn't working. NOTE: tox doesn't allow us to easily
execute shell scripts and commands outside its virtualenv so I have to
resort to ugly bash escaping to make this work!

Finally properly fixes #96.
---
 .travis.yml             | 10 +++++++---
 pylint_django/plugin.py |  9 +++++++--
 tox.ini                 |  3 +++
 3 files changed, 17 insertions(+), 5 deletions(-)

diff --git a/.travis.yml b/.travis.yml
index 6258fd4c..9ed2fe9e 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -7,14 +7,18 @@ python:
 env:
   - DJANGO=1.11
   - DJANGO=2.0
+stages:
+  - django_not_installed
+  - test
 matrix:
   exclude:
     # Python/Django combinations that aren't officially supported
     - { python: 2.7, env: DJANGO=2.0 }
   include:
-    - { python: 3.6, env: TOXENV=flake8 }
-    - { python: 3.6, env: TOXENV=pylint }
-    - { python: 3.6, env: TOXENV=readme }
+    - { stage: django_not_installed, python: 3.6, env: TOXENV=django_not_installed }
+    - { stage: test, python: 3.6, env: TOXENV=flake8 }
+    - { stage: test, python: 3.6, env: TOXENV=pylint }
+    - { stage: test, python: 3.6, env: TOXENV=readme }
   allow_failures:
     - env: TOXENV=flake8
     - env: TOXENV=pylint
diff --git a/pylint_django/plugin.py b/pylint_django/plugin.py
index 06fb6f4d..9420e351 100644
--- a/pylint_django/plugin.py
+++ b/pylint_django/plugin.py
@@ -2,7 +2,6 @@
 from pylint.checkers.base import NameChecker
 from pylint_plugin_utils import get_checker
 
-from pylint_django.augmentations import apply_augmentations
 from pylint_django.checkers import register_checkers
 
 # we want to import the transforms to make sure they get added to the astroid manager,
@@ -26,4 +25,10 @@ def register(linter):
     register_checkers(linter)
 
     # register any checking fiddlers
-    apply_augmentations(linter)
+    try:
+        from pylint_django.augmentations import apply_augmentations
+        apply_augmentations(linter)
+    except ModuleNotFoundError:
+        # probably trying to execute pylint_django when Django isn't installed
+        # in this case the django-not-installed checker will kick-in
+        pass
diff --git a/tox.ini b/tox.ini
index 3f374773..350c073a 100644
--- a/tox.ini
+++ b/tox.ini
@@ -3,6 +3,7 @@
 
 [tox]
 envlist =
+    django_not_installed
     flake8
     pylint
     readme
@@ -11,6 +12,7 @@ envlist =
 
 [testenv]
 commands =
+    django_not_installed: bash -c \'pylint --load-plugins=pylint_django setup.py | grep django-not-available\'
     flake8: flake8
     pylint: pylint --rcfile=tox.ini pylint_django setup
     readme: python setup.py check --restructuredtext --strict
@@ -35,6 +37,7 @@ setenv =
     PIP_DISABLE_PIP_VERSION_CHECK = 1
     PYTHONPATH = .
 whitelist_externals =
+    django_not_installed: bash
     clean: find
     clean: rm