Handle duplicate column names in CSV import

- display a warning message to the user
- automatically rename columns by adding "__1", "__2", ... suffixes

src/pretix/base/modelimport.py

@@ -47,6 +47,19 @@ class DataImportError(LazyLocaleException):
         super().__init__(msg)
 
 
+def rename_duplicates(values):
+    used = set()
+    had_duplicates = False
+    for i, value in enumerate(values):
+        c = 0
+        while values[i] in used:
+            c += 1
+            values[i] = f'{value}__{c}'
+            had_duplicates = True
+        used.add(values[i])
+    return had_duplicates
+
+
 def parse_csv(file, length=None, mode="strict", charset=None):
     file.seek(0)
     data = file.read(length)
@@ -70,6 +83,7 @@ def parse_csv(file, length=None, mode="strict", charset=None):
         return None
 
     reader = csv.DictReader(io.StringIO(data), dialect=dialect)
+    reader._had_duplicates = rename_duplicates(reader.fieldnames)
     return reader
 
 

src/pretix/control/views/modelimport.py

@@ -146,7 +146,7 @@ class BaseProcessView(AsyncAction, FormView):
         else:
             charset = None
         try:
-            return parse_csv(self.file.file, 1024 * 1024, charset=charset)
+            reader = parse_csv(self.file.file, 1024 * 1024, charset=charset)
         except UnicodeDecodeError:
             messages.warning(
                 self.request,
@@ -155,7 +155,16 @@ class BaseProcessView(AsyncAction, FormView):
                     "Some characters were replaced with a placeholder."
                 )
             )
-            return parse_csv(self.file.file, 1024 * 1024, "replace", charset=charset)
+            reader = parse_csv(self.file.file, 1024 * 1024, "replace", charset=charset)
+        if reader._had_duplicates:
+            messages.warning(
+                self.request,
+                _(
+                    "Multiple columns of the CSV file have the same name and were renamed automatically. We "
+                    "recommend that you rename these in your source file to avoid problems during import."
+                )
+            )
+        return reader
 
     @cached_property
     def parsed_list(self):

src/pretix/plugins/paypal2/payment.py

@@ -711,7 +711,7 @@ class PaypalMethod(BasePaymentProvider):
                         description = '{prefix}{orderstring}{postfix}'.format(
                             prefix='{} '.format(self.settings.prefix) if self.settings.prefix else '',
                             orderstring=__('Order {order} for {event}').format(
-                                event=self.event.name,
+                                event=request.event.name,
                                 order=payment.order.code
                             ),
                             postfix=' {}'.format(self.settings.postfix) if self.settings.postfix else ''

src/pretix/plugins/sendmail/tasks.py

@@ -47,14 +47,6 @@ from pretix.celery_app import app
 from pretix.helpers.format import format_map
 
 
-def _chunks(lst, n):
-    """
-    Yield successive n-sized chunks from lst.
-    """
-    for i in range(0, len(lst), n):
-        yield lst[i:i + n]
-
-
 @app.task(base=ProfiledEventTask, acks_late=True)
 def send_mails_to_orders(event: Event, user: int, subject: dict, message: dict, objects: list, items: list,
                          subevent: int, subevents_from: datetime, subevents_to: datetime,
@@ -63,11 +55,12 @@ def send_mails_to_orders(event: Event, user: int, subject: dict, message: dict,
                          attach_ical: bool = False) -> None:
     failures = []
     user = User.objects.get(pk=user) if user else None
+    orders = Order.objects.filter(pk__in=objects, event=event)
     subject = LazyI18nString(subject)
     message = LazyI18nString(message)
     attachments_for_log = [cf.filename for cf in CachedFile.objects.filter(pk__in=attachments)] if attachments else []
 
-    def _send_to_order(o):
+    for o in orders:
         send_to_order = recipients in ('both', 'orders')
 
         try:
@@ -186,11 +179,6 @@ def send_mails_to_orders(event: Event, user: int, subject: dict, message: dict,
             except SendMailException:
                 failures.append(o.email)
 
-    for chunk in _chunks(objects, 1000):
-        orders = Order.objects.filter(pk__in=chunk, event=event)
-        for o in orders:
-            _send_to_order(o)
-
 
 @app.task(base=ProfiledEventTask, acks_late=True)
 def send_mails_to_waitinglist(event: Event, user: int, subject: dict, message: dict, objects: list,

src/pretix/static/pretixbase/scss/_bootstrap_vars.scss

@@ -67,7 +67,7 @@ $panel-success-heading-bg: var(--pretix-brand-success-tint-50);
 $panel-danger-border: var(--pretix-brand-danger-tint-50);
 $panel-danger-heading-bg: var(--pretix-brand-danger-tint-50);
 $panel-warning-border: var(--pretix-brand-warning-tint-50);
-$panel-warning-heading-bg: var(--pretix-brand-warning-tint-50);
+$panel-warning-heading-bg: var(--pretix-brand-warning-tine-50);
 $panel-default-border: #e5e5e5 !default;
 $panel-default-heading-bg: #e5e5e5 !default;