Improve error messages for name-parts inputs (Z#23234440) (#6187)

* Improve error messages for name-parts inputs (Z#23234440)

* fix isort after flake8

* correct spelling of .med in user-provided title/name

* fix search instead of match

src/pretix/base/forms/questions.py

@@ -35,6 +35,7 @@
 import copy
 import json
 import logging
+import re
 from datetime import timedelta
 from decimal import Decimal
 from io import BytesIO
@@ -47,9 +48,7 @@ from django.conf import settings
 from django.contrib import messages
 from django.core.exceptions import ValidationError
 from django.core.files.uploadedfile import SimpleUploadedFile
-from django.core.validators import (
+from django.core.validators import MaxValueValidator, MinValueValidator
-    MaxValueValidator, MinValueValidator, RegexValidator,
-)
 from django.db.models import QuerySet
 from django.forms import Select, widgets
 from django.forms.widgets import FILE_INPUT_CONTRADICTION
@@ -220,20 +219,6 @@ class NamePartsFormField(forms.MultiValueField):
         defaults = {
             'widget': self.widget,
             'max_length': kwargs.pop('max_length', None),
-            'validators': [
-                RegexValidator(
-                    # The following characters should never appear in a name anywhere of
-                    # the world. However, they commonly appear in inputs generated by spam
-                    # bots.
-                    r'^[^$€/%§{}<>~]*$',
-                    message=_('Please do not use special characters in names.')
-                ),
-                RegexValidator(
-                    URL_RE,
-                    inverse_match=True,
-                    message=_('Please do not use special characters in names.')
-                )
-            ]
         }
         self.max_length = defaults['max_length']
         self.scheme_name = kwargs.pop('scheme')
@@ -255,7 +240,6 @@ class NamePartsFormField(forms.MultiValueField):
             if fname == 'title' and self.scheme_titles:
                 d = dict(defaults)
                 d.pop('max_length', None)
-                d.pop('validators', None)
                 field = forms.ChoiceField(
                     **d,
                     choices=[('', '')] + [(d, d) for d in self.scheme_titles[1]]
@@ -264,7 +248,6 @@ class NamePartsFormField(forms.MultiValueField):
             elif fname == 'salutation':
                 d = dict(defaults)
                 d.pop('max_length', None)
-                d.pop('validators', None)
                 field = forms.ChoiceField(
                     **d,
                     choices=[
@@ -296,6 +279,37 @@ class NamePartsFormField(forms.MultiValueField):
         if sum(len(v) for v in value.values() if v) > (self.max_length or 250):
             raise forms.ValidationError(_('Please enter a shorter name.'), code='max_length')
 
+        for fname, label, size in self.scheme['fields']:
+            if fname == 'salutation' or (fname == 'title' and self.scheme_titles):
+                continue
+            v = value.get(fname)
+            if not v:
+                continue
+            special_chars = re.findall('[$€/%§{}<>~]', v)
+            if special_chars:
+                raise forms.ValidationError(
+                    _('The field "%(label)s" may not contain special characters such as "%(chars)s".'),
+                    code='name_special_chars',
+                    params={
+                        "label": label,
+                        "chars": "".join(special_chars),
+                    },
+                )
+            # URL_RE checks for valid domain names, including one special TLD med, which can be part of a title
+            if ".med" in v:
+                v = v.replace(".med", ". med")
+                value[fname] = v
+            url_matched = URL_RE.search(v)
+            if url_matched:
+                raise forms.ValidationError(
+                    _('The field "%(label)s" may not contain an URL (%(url)s).'),
+                    code='url_in_title',
+                    params={
+                        "label": label,
+                        "url": url_matched.group(0),
+                    }
+                )
+
         if value.get("salutation") == "empty":
             value["salutation"] = ""