Handle errors while sending emails around changing user data

The most common error is Amazon SES having blacklisted an email address.
However, we handle any error being raised during user.email_user.

Fixes JIRA LMS-131

common/djangoapps/student/tests/factories.py

 from student.models import (User, UserProfile, Registration,
-                            CourseEnrollmentAllowed, CourseEnrollment)
+                            CourseEnrollmentAllowed, CourseEnrollment,
+                            PendingEmailChange)
 from django.contrib.auth.models import Group
 from datetime import datetime
 from factory import DjangoModelFactory, SubFactory, PostGenerationMethodCall, post_generation, Sequence
 from uuid import uuid4
 
+# Factories don't have __init__ methods, and are self documenting
+# pylint: disable=W0232
+
 
 class GroupFactory(DjangoModelFactory):
     FACTORY_FOR = Group
@@ -72,3 +76,17 @@ class CourseEnrollmentAllowedFactory(DjangoModelFactory):
 
     email = 'test@edx.org'
     course_id = 'edX/test/2012_Fall'
+
+
+class PendingEmailChangeFactory(DjangoModelFactory):
+    """Factory for PendingEmailChange objects
+
+    user: generated by UserFactory
+    new_email: sequence of new+email+{}@edx.org
+    activation_key: sequence of integers, padded to 30 characters
+    """
+    FACTORY_FOR = PendingEmailChange
+
+    user = SubFactory(UserFactory)
+    new_email = Sequence(u'new+email+{0}@edx.org'.format)
+    activation_key = Sequence(u'{:0<30d}'.format)

common/djangoapps/student/views.py

@@ -19,7 +19,7 @@ from django.core.context_processors import csrf
 from django.core.mail import send_mail
 from django.core.urlresolvers import reverse
 from django.core.validators import validate_email, validate_slug, ValidationError
-from django.db import IntegrityError
+from django.db import IntegrityError, transaction
 from django.http import HttpResponse, HttpResponseBadRequest, HttpResponseForbidden, HttpResponseNotAllowed, HttpResponseRedirect, Http404
 from django.shortcuts import redirect
 from django_future.csrf import ensure_csrf_cookie, csrf_exempt
@@ -655,7 +655,7 @@ def create_account(request, post_override=None):
         elif not settings.GENERATE_RANDOM_USER_CREDENTIALS:
             res = user.email_user(subject, message, settings.DEFAULT_FROM_EMAIL)
     except:
-        log.exception(sys.exc_info())
+        log.warning('Unable to send activation email to user', exc_info=True)
         js['value'] = 'Could not send activation e-mail.'
         return HttpResponse(json.dumps(js))
 
@@ -975,7 +975,11 @@ def reactivation_email_for_user(user):
     subject = ''.join(subject.splitlines())
     message = render_to_string('emails/activation_email.txt', d)
 
-    res = user.email_user(subject, message, settings.DEFAULT_FROM_EMAIL)
+    try:
+        res = user.email_user(subject, message, settings.DEFAULT_FROM_EMAIL)
+    except:
+        log.warning('Unable to send reactivation email', exc_info=True)
+        return HttpResponse(json.dumps({'success': False, 'error': 'Unable to send reactivation email'}))
 
     return HttpResponse(json.dumps({'success': True}))
 
@@ -1001,7 +1005,7 @@ def change_email_request(request):
         return HttpResponse(json.dumps({'success': False,
                                         'error': 'Valid e-mail address required.'}))
 
-    if len(User.objects.filter(email=new_email)) != 0:
+    if User.objects.filter(email=new_email).count() != 0:
         ## CRITICAL TODO: Handle case sensitivity for e-mails
         return HttpResponse(json.dumps({'success': False,
                                         'error': 'An account with this e-mail already exists.'}))
@@ -1036,41 +1040,63 @@ def change_email_request(request):
 
 
 @ensure_csrf_cookie
+@transaction.commit_manually
 def confirm_email_change(request, key):
     ''' User requested a new e-mail. This is called when the activation
     link is clicked. We confirm with the old e-mail, and update
     '''
     try:
-        pec = PendingEmailChange.objects.get(activation_key=key)
-    except PendingEmailChange.DoesNotExist:
-        return render_to_response("invalid_email_key.html", {})
-
-    user = pec.user
-    d = {'old_email': user.email,
-         'new_email': pec.new_email}
+        try:
+            pec = PendingEmailChange.objects.get(activation_key=key)
+        except PendingEmailChange.DoesNotExist:
+            transaction.rollback()
+            return render_to_response("invalid_email_key.html", {})
+
+        user = pec.user
+        address_context = {
+            'old_email': user.email,
+            'new_email': pec.new_email
+        }
 
-    if len(User.objects.filter(email=pec.new_email)) != 0:
-        return render_to_response("email_exists.html", d)
+        if len(User.objects.filter(email=pec.new_email)) != 0:
+            transaction.rollback()
+            return render_to_response("email_exists.html", {})
+
+        subject = render_to_string('emails/email_change_subject.txt', address_context)
+        subject = ''.join(subject.splitlines())
+        message = render_to_string('emails/confirm_email_change.txt', address_context)
+        up = UserProfile.objects.get(user=user)
+        meta = up.get_meta()
+        if 'old_emails' not in meta:
+            meta['old_emails'] = []
+        meta['old_emails'].append([user.email, datetime.datetime.now().isoformat()])
+        up.set_meta(meta)
+        up.save()
+        # Send it to the old email...
+        try:
+            user.email_user(subject, message, settings.DEFAULT_FROM_EMAIL)
+        except Exception:
+            transaction.rollback()
+            log.warning('Unable to send confirmation email to old address', exc_info=True)
+            return render_to_response("email_change_failed.html", {'email': user.email})
 
-    subject = render_to_string('emails/email_change_subject.txt', d)
-    subject = ''.join(subject.splitlines())
-    message = render_to_string('emails/confirm_email_change.txt', d)
-    up = UserProfile.objects.get(user=user)
-    meta = up.get_meta()
-    if 'old_emails' not in meta:
-        meta['old_emails'] = []
-    meta['old_emails'].append([user.email, datetime.datetime.now().isoformat()])
-    up.set_meta(meta)
-    up.save()
-    # Send it to the old email...
-    user.email_user(subject, message, settings.DEFAULT_FROM_EMAIL)
-    user.email = pec.new_email
-    user.save()
-    pec.delete()
-    # And send it to the new email...
-    user.email_user(subject, message, settings.DEFAULT_FROM_EMAIL)
-
-    return render_to_response("email_change_successful.html", d)
+        user.email = pec.new_email
+        user.save()
+        pec.delete()
+        # And send it to the new email...
+        try:
+            user.email_user(subject, message, settings.DEFAULT_FROM_EMAIL)
+        except Exception:
+            transaction.rollback()
+            log.warning('Unable to send confirmation email to new address', exc_info=True)
+            return render_to_response("email_change_failed.html", {'email': pec.new_email})
+
+        transaction.commit()
+        return render_to_response("email_change_successful.html", address_context)
+    except Exception:
+        # If we get an unexpected exception, be sure to rollback the transaction
+        transaction.rollback()
+        raise
 
 
 @ensure_csrf_cookie

lms/templates/email_change_failed.html

+<h1>E-mail change failed.</h1>
+
+<p>We were unable to send a confirmation email to ${email}</p>

pylintrc

@@ -110,7 +110,9 @@ generated-members=
     get_url,
     size,
     content,
-    status_code
+    status_code,
+# For factory_body factories
+    create
 
 
 [BASIC]

requirements/edx/base.txt

@@ -71,7 +71,7 @@ transifex-client==0.8
 coverage==3.6
 factory_boy==2.0.2
 lettuce==0.2.16
-mock==0.8.0
+mock==1.0.1
 nosexcover==1.0.7
 pep8==1.4.5
 pylint==0.28