Fix #565 -- Support empty_label on ModelSelect fields.

Author: codingjoe

django_select2/forms.py

@@ -70,14 +70,16 @@ class Select2Mixin:
     form media.
     """
 
+    empty_label = ''
+
     def build_attrs(self, base_attrs, extra_attrs=None):
         """Add select2 data attributes."""
         default_attrs = {'data-minimum-input-length': 0}
         if self.is_required:
             default_attrs['data-allow-clear'] = 'false'
         else:
             default_attrs['data-allow-clear'] = 'true'
-            default_attrs['data-placeholder'] = ''
+            default_attrs['data-placeholder'] = self.empty_label
 
         default_attrs.update(base_attrs)
         attrs = super().build_attrs(default_attrs, extra_attrs=extra_attrs)
@@ -208,6 +210,7 @@ def __init__(self, attrs=None, choices=(), **kwargs):
                 widget could be dependent on a country.
                 Key is a name of a field in a form.
                 Value is a name of a field in a model (used in `queryset`).
+
         """
         self.choices = choices
         if attrs is not None:
@@ -339,6 +342,12 @@ class ModelSelect2Mixin:
     max_results = 25
     """Maximal results returned by :class:`.AutoResponseView`."""
 
+    @property
+    def empty_label(self):
+        if isinstance(self.choices, ModelChoiceIterator):
+            return self.choices.field.empty_label
+        return ''
+
     def __init__(self, *args, **kwargs):
         """
         Overwrite class parameters if passed as keyword arguments.

tests/conftest.py

@@ -21,7 +21,7 @@ def random_name(n):
 @pytest.yield_fixture(scope='session')
 def driver():
     chrome_options = webdriver.ChromeOptions()
-    chrome_options.headless = False
+    chrome_options.headless = True
     try:
         b = webdriver.Chrome(options=chrome_options)
     except WebDriverException as e:

tests/test_forms.py

@@ -412,6 +412,14 @@ def test_custom_to_field_name(self):
         form = forms.GroupieForm(instance=groupie)
         assert '<option value="Take That" selected>TAKE THAT</option>' in form.as_p()
 
+    def test_empty_label(self, db):
+        # Empty options is only required for single selects
+        # https://select2.github.io/options.html#allowClear
+        single_select = self.form.fields['primary_genre']
+        single_select.empty_label = 'Hello World'
+        assert single_select.required is False
+        assert 'data-placeholder="Hello World"' in single_select.widget.render('primary_genre', None)
+
 
 class TestHeavySelect2TagWidget(TestHeavySelect2Mixin):