Validate the slug field in CopyForm against invalid characters

wagtail/wagtailadmin/forms.py

@@ -85,7 +85,7 @@ class CopyForm(forms.Form):
         super(CopyForm, self).__init__(*args, **kwargs)
 
         self.fields['new_title'] = forms.CharField(initial=self.page.title)
-        self.fields['new_slug'] = forms.CharField(initial=self.page.slug)
+        self.fields['new_slug'] = forms.SlugField(initial=self.page.slug)
 
     copy_subpages = forms.BooleanField(required=False, initial=True)
     publish_copies = forms.BooleanField(required=False, initial=True)

wagtail/wagtailadmin/tests/test_pages_views.py

@@ -1127,6 +1127,21 @@ class TestPageCopy(TestCase, WagtailTestUtils):
         # Check that a form error was raised
         self.assertFormError(response, 'form', 'new_slug', "This slug is already in use")
 
+    def test_page_copy_post_invalid_slug(self):
+        # Attempt to copy the page but set an invalid slug string
+        post_data = {
+            'new_title': "Hello world 2",
+            'new_slug': 'hello world!',
+            'copy_subpages': False,
+        }
+        response = self.client.post(reverse('wagtailadmin_pages_copy', args=(self.test_page.id, )), post_data)
+
+        # Should not be redirected (as the save should fail)
+        self.assertEqual(response.status_code, 200)
+
+        # Check that a form error was raised
+        self.assertFormError(response, 'form', 'new_slug', "Enter a valid 'slug' consisting of letters, numbers, underscores or hyphens.")
+
     def test_page_copy_no_publish_permission(self):
         # Turn user into an editor who can add pages but not publish them
         self.user.is_superuser = False