emails: Add html versions of emails that do not have them.

Fixes #4691.

templates/zerver/emails/notify_change_in_email.html

@@ -0,0 +1,12 @@
+{% extends "zerver/emails/email_base.html" %}
+
+{% block content %}
+<p>Hi,</p>
+<p>
+    We just wanted to let you know that the email associated with your Zulip account was recently changed to <a href="{{ new_email }}" style="color:#08c">{{ new_email }}</a>. If you did not request this change, please contact us immediately at <a href="mailto:{{ support_email }}" style="color:#08c">{{ support_email }}</a>.
+</p>
+<p>
+    Best,<br />
+    The Zulip Team
+</p>
+{% endblock %}

templates/zerver/emails/password_reset.html

@@ -0,0 +1,17 @@
+{% extends "zerver/emails/email_base.html" %}
+
+{% block content %}
+<p>
+    {% if attempted_realm %}
+    Someone (possibly you) requested a password reset email for {{ email }} on {{ attempted_realm.uri }}, but {{ email }} does not have an active account in {{ attempted_realm.uri }}.  However, {{ email }} does have an active account in {{ user.realm.uri }} organization; you can try logging in or resetting your password there.
+    {% else %}
+    Psst. Word on the street is that you forgot your password, {{ email }}.<br />
+    It's all good. Follow the link below and we'll take care of the rest:<br />
+    {{ protocol }}://{{ user.realm.host }}{{ url('django.contrib.auth.views.password_reset_confirm', kwargs=dict(uidb64=uid, token=token)) }}
+    {% endif %}
+</p>
+<p>
+    Thanks,<br />
+    Your friends at Zulip HQ
+</p>
+{% endblock %}

zerver/lib/send_email.py

@@ -1,6 +1,6 @@
 from django.conf import settings
 from django.core.mail import EmailMultiAlternatives
-from django.template import loader, TemplateDoesNotExist
+from django.template import loader
 from django.utils.timezone import now as timezone_now
 from zerver.models import UserProfile, ScheduledJob
 
@@ -27,11 +27,7 @@ def build_email(template_prefix, to_email, from_email=None, reply_to_email=None,
                                       context=context, using='Jinja2_plaintext').strip()
     message = loader.render_to_string(template_prefix + '.txt',
                                       context=context, using='Jinja2_plaintext')
-    # Remove try/expect once https://github.com/zulip/zulip/issues/4691 is resolved.
-    try:
-        html_message = loader.render_to_string(template_prefix + '.html', context)
-    except TemplateDoesNotExist:
-        html_message = None
+    html_message = loader.render_to_string(template_prefix + '.html', context)
     if from_email is None:
         from_email = settings.NOREPLY_EMAIL_ADDRESS
     reply_to = None

zerver/tests/test_templates.py

@@ -90,6 +90,7 @@ class TemplateTestCase(ZulipTestCase):
             'zerver/emails/confirm_new_email.html',
             'zerver/emails/confirm_new_email.txt',
             'zerver/emails/notify_change_in_email.subject',
+            'zerver/emails/notify_change_in_email.html',
             'zerver/emails/digest.subject',
             'zerver/emails/digest.html',
             'zerver/emails/digest.txt',
@@ -99,6 +100,7 @@ class TemplateTestCase(ZulipTestCase):
             'zerver/emails/followup_day2.subject',
             'zerver/emails/followup_day2.txt',
             'zerver/emails/followup_day2.html',
+            'zerver/emails/password_reset.html',
             'corporate/mit.html',
             'corporate/zephyr.html',
             'corporate/zephyr-mirror.html',