Fix #635 -- Visually indicate optional and required fields (#638)

src/pretix/control/forms/renderers.py

@@ -0,0 +1,54 @@
+from bootstrap3.renderers import FieldRenderer
+from bootstrap3.text import text_value
+from django.forms import CheckboxInput
+from django.forms.utils import flatatt
+from django.utils.html import format_html
+from django.utils.safestring import mark_safe
+from django.utils.translation import pgettext
+from i18nfield.forms import I18nFormField
+
+
+def render_label(content, label_for=None, label_class=None, label_title='', optional=False):
+    """
+    Render a label with content
+    """
+    attrs = {}
+    if label_for:
+        attrs['for'] = label_for
+    if label_class:
+        attrs['class'] = label_class
+    if label_title:
+        attrs['title'] = label_title
+    builder = '<{tag}{attrs}>{content}{opt}</{tag}>'
+    return format_html(
+        builder,
+        tag='label',
+        attrs=mark_safe(flatatt(attrs)) if attrs else '',
+        opt=mark_safe('<br><span class="optional">{}</span>'.format(pgettext('form', 'Optional'))) if optional else '',
+        content=text_value(content),
+    )
+
+
+class ControlFieldRenderer(FieldRenderer):
+    def __init__(self, *args, **kwargs):
+        kwargs['layout'] = 'horizontal'
+        super().__init__(*args, **kwargs)
+
+    def add_label(self, html):
+        label = self.get_label()
+
+        if hasattr(self.field.field, '_required'):
+            # e.g. payment settings forms where a field is only required if the payment provider is active
+            required = self.field.field._required
+        elif isinstance(self.field.field, I18nFormField):
+            required = self.field.field.one_required
+        else:
+            required = self.field.field.required
+
+        html = render_label(
+            label,
+            label_for=self.field.id_for_label,
+            label_class=self.get_label_class(),
+            optional=not required and not isinstance(self.widget, CheckboxInput)
+        ) + html
+        return html