Remove a Language

[arifin4web]

As suggested in the issue #10 pre_delete signal couldn't be used. The signal doesn't Trigger before raising ProtectedError. Therefore Implemented a custom delete view for LanguageModelAdmin which will:

1. Show a clear warning to the user, which related Translatable pages are going to be removed.
2. Remove those pages and language itself.

[codecov[bot]]

Codecov Report

Merging #100 into master will increase coverage by 0.36%. The diff coverage is 100%.

@@            Coverage Diff             @@
##           master     #100      +/-   ##
==========================================
+ Coverage    89.5%   89.86%   +0.36%     
==========================================
  Files          14       16       +2     
  Lines         505      523      +18     
==========================================
+ Hits          452      470      +18     
  Misses         53       53

Impacted Files	Coverage Δ
...gtailtrans/templatetags/languages_wagtail_admin.py	100% <100%> (ø)
src/wagtailtrans/views/language.py	100% <100%> (ø)

[arifin4web]

reviews are implemented! @mikedingjan

[arifin4web]

Whats the update on this one? can this be merged now?

[jjanssen]

Hi @arifin4web, It is awaiting review and I want to take it for a spin really soon.

[jjanssen]

I'm getting the following stacktrace when I click on delete language:

TemplateSyntaxError at /admin/wagtailtrans/language/delete/3/
Invalid block tag on line 15: 'get_language_relate_pages', expected 'endif'. Did you forget to register or load this tag?

Can we fix this and add a test for that?

Stacktrace

Environment:


Request Method: GET
Request URL: http://localhost:8000/admin/wagtailtrans/language/delete/3/

Django Version: 1.10.5
Python Version: 2.7.10
Installed Applications:
['django.contrib.admin',
 'django.contrib.auth',
 'django.contrib.contenttypes',
 'django.contrib.sessions',
 'django.contrib.messages',
 'django.contrib.staticfiles',
 'wagtail.contrib.settings',
 'wagtail.contrib.modeladmin',
 'wagtail.wagtailforms',
 'wagtail.wagtailredirects',
 'wagtail.wagtailembeds',
 'wagtail.wagtailsites',
 'wagtail.wagtailusers',
 'wagtail.wagtailsnippets',
 'wagtail.wagtaildocs',
 'wagtail.wagtailimages',
 'wagtail.wagtailsearch',
 'wagtail.wagtailadmin',
 'wagtail.wagtailcore',
 'wagtailtrans',
 'modelcluster',
 'taggit',
 'tests._sandbox.pages',
 'tests._sandbox.search']
Installed Middleware:
['django.middleware.security.SecurityMiddleware',
 'django.contrib.sessions.middleware.SessionMiddleware',
 'django.middleware.common.CommonMiddleware',
 'django.middleware.csrf.CsrfViewMiddleware',
 'django.contrib.auth.middleware.AuthenticationMiddleware',
 'django.contrib.auth.middleware.SessionAuthenticationMiddleware',
 'django.contrib.messages.middleware.MessageMiddleware',
 'django.middleware.clickjacking.XFrameOptionsMiddleware',
 'wagtail.wagtailcore.middleware.SiteMiddleware',
 'wagtail.wagtailredirects.middleware.RedirectMiddleware',
 'wagtailtrans.middleware.TranslationMiddleware']


Template error:
In template /Users/j.janssen/Sites/git-projects/wagtailtrans/src/wagtailtrans/templates/modeladmin/wagtailtrans/language/delete.html, error at line 15
   Invalid block tag on line 15: 'get_language_relate_pages', expected 'endif'. Did you forget to register or load this tag?   5 :     <div class="nice-padding">
   6 :         {% if protected_error %}
   7 :             <h2>{% blocktrans with view.verbose_name|capfirst as model_name %}{{ model_name }} could not be deleted{% endblocktrans %}</h2>
   8 :             <p>{% blocktrans with instance as instance_name %}'{{ instance_name }}' is currently referenced by other objects, and cannot be deleted without jeopardising data integrity. To delete it successfully, first remove references from the following objects, then try again:{% endblocktrans %}</p>
   9 :             <ul>
   10 :                 {% for obj in linked_objects %}<li><b>{{ obj|get_content_type_for_obj|title }}:</b> {{ obj }}</li>{% endfor %}
   11 :             </ul>
   12 :             <p><a href="{{ view.index_url }}" class="button">{% trans 'Go back to listing' %}</a></p>
   13 :         {% else %}
   14 :             <p>{{ view.confirmation_message }}</p>
   15 :              {% get_language_relate_pages instance as related_pages %} 
   16 :             {% if related_pages %}
   17 :                 {% with instance as instance_name %}
   18 :                 <p>{% blocktrans %}'{{ instance_name }}' is currently referenced by Following TranslatablePage : {% endblocktrans %}</p>
   19 :                 <ul>
   20 :                     {% for obj in related_pages %}<li><b>{{ obj }} ({{instance_name}})</b></li>{% endfor %}
   21 :                 </ul>
   22 :                 <p>{% blocktrans %} If you delete the language '{{ instance_name }}', All of these pages will also be deleted. {% endblocktrans %}</p>
   23 :                 {% endwith %}
   24 :             {% endif %}
   25 :             <form action="{{ view.delete_url }}" method="POST">

File "/Users/j.janssen/.virtualenvs/wagtailtrans/lib/python2.7/site-packages/django/core/handlers/exception.py" in inner
  39.             response = get_response(request)

File "/Users/j.janssen/.virtualenvs/wagtailtrans/lib/python2.7/site-packages/django/core/handlers/base.py" in _get_response
  217.                 response = self.process_exception_by_middleware(e, request)

File "/Users/j.janssen/.virtualenvs/wagtailtrans/lib/python2.7/site-packages/django/core/handlers/base.py" in _get_response
  215.                 response = response.render()

File "/Users/j.janssen/.virtualenvs/wagtailtrans/lib/python2.7/site-packages/django/template/response.py" in render
  109.             self.content = self.rendered_content

File "/Users/j.janssen/.virtualenvs/wagtailtrans/lib/python2.7/site-packages/django/template/response.py" in rendered_content
  84.         template = self.resolve_template(self.template_name)

File "/Users/j.janssen/.virtualenvs/wagtailtrans/lib/python2.7/site-packages/django/template/response.py" in resolve_template
  66.             return select_template(template, using=self.using)

File "/Users/j.janssen/.virtualenvs/wagtailtrans/lib/python2.7/site-packages/django/template/loader.py" in select_template
  48.                 return engine.get_template(template_name)

File "/Users/j.janssen/.virtualenvs/wagtailtrans/lib/python2.7/site-packages/django/template/backends/django.py" in get_template
  39.             return Template(self.engine.get_template(template_name), self)

File "/Users/j.janssen/.virtualenvs/wagtailtrans/lib/python2.7/site-packages/django/template/engine.py" in get_template
  160.         template, origin = self.find_template(template_name)

File "/Users/j.janssen/.virtualenvs/wagtailtrans/lib/python2.7/site-packages/django/template/engine.py" in find_template
  134.                         name, template_dirs=dirs, skip=skip,

File "/Users/j.janssen/.virtualenvs/wagtailtrans/lib/python2.7/site-packages/django/template/loaders/base.py" in get_template
  44.                     contents, origin, origin.template_name, self.engine,

File "/Users/j.janssen/.virtualenvs/wagtailtrans/lib/python2.7/site-packages/django/template/base.py" in __init__
  191.         self.nodelist = self.compile_nodelist()

File "/Users/j.janssen/.virtualenvs/wagtailtrans/lib/python2.7/site-packages/django/template/base.py" in compile_nodelist
  233.             return parser.parse()

File "/Users/j.janssen/.virtualenvs/wagtailtrans/lib/python2.7/site-packages/django/template/base.py" in parse
  518.                     raise self.error(token, e)

Exception Type: TemplateSyntaxError at /admin/wagtailtrans/language/delete/3/
Exception Value: Invalid block tag on line 15: 'get_language_relate_pages', expected 'endif'. Did you forget to register or load this tag?

[jjanssen]

Hi @arifin4web

I took a moment to make the overview for deletion a little more appealing. Last thing I noticed when we would be deleting a canonical language it would also be relevant to show the impact of connected pages which are linked to the canonical language.

For eg we have the following languages:

• English (default)
• Dutch

Deleting English will also delete Dutch. It is this something we can show accordingly in the list of pages we are about to delete?

[mikedingjan]

As I remember correctly the canonical_page is a foreign key with models.SET_NULL e.g. when removing a default language it'll remove all pages of that language, and make all the other pages canonical, no more linked pages at all.

Because we have a signal which synchronises the deletion of pages with SYNC_TREE=True this will have other behaviour than expected.

So we can either disconnect the pre_delete signal for this specific use-case. An other option is to disallow the removal of the default language when SYNC_TREE=True and other languages are still in the database.

Thing to keep in mind, LANGUAGES_PER_SITE=True can be tricky with this.

[arifin4web]

I apologize for being so late with this MR.

My opinion about removing a default language is that we should never allow them to be deleted. One of the reason being, after we delete a default language we wouldn't be able to create a translatable page. We have to create/set another language as default.