From fae07a449eb4eccba2ffab3c082534f3a4eda0f7 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Corentin=20S=C3=A9chet?= <csechet@entrouvert.com>
Date: Mon, 4 Jul 2022 21:22:00 +0200
Subject: [PATCH] publik: add |first template filter (#66955)

---
 .../publik/templatetags/publik.py                |  9 +++++++++
 tests/test_publik.py                             | 16 ++++++++++++++++
 2 files changed, 25 insertions(+)

diff --git a/publik_django_templatetags/publik/templatetags/publik.py b/publik_django_templatetags/publik/templatetags/publik.py
index 97b7265..8a03e34 100644
--- a/publik_django_templatetags/publik/templatetags/publik.py
+++ b/publik_django_templatetags/publik/templatetags/publik.py
@@ -15,6 +15,7 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 from django import template
+from django.template import defaultfilters
 
 register = template.Library()
 
@@ -45,3 +46,11 @@ def getlist(mapping, key):
 @register.filter(name='list')
 def as_list(obj):
     return list(obj)
+
+
+@register.filter
+def first(value):
+    try:
+        return defaultfilters.first(value)
+    except TypeError:
+        return ''
diff --git a/tests/test_publik.py b/tests/test_publik.py
index c5bd16f..d83d244 100644
--- a/tests/test_publik.py
+++ b/tests/test_publik.py
@@ -52,3 +52,19 @@ def test_getlist():
     t = Template('{% for v in values|getlist:"k"|getlist:"v" %}{{ v }},{% endfor %}')
     context = Context({'values': [{'k': None}, {'k': {'v': 'baz'}}]})
     assert t.render(context) == 'None,baz,'
+
+
+def test_first():
+    t = Template('{{ foo|first }}')
+
+    context = Context({'foo': ['foo']})
+    assert t.render(context) == 'foo'
+
+    context = Context({'foo': 'foo'})
+    assert t.render(context) == 'f'
+
+    context = Context({'foo': ''})
+    assert t.render(context) == ''
+
+    context = Context({'foo': None})
+    assert t.render(context) == ''