Fixed #19226 -- Applied linebreaksbr to read-only fields in admin

Thanks shadow for the report, and Melevir and thiderman for the
patch.

django/contrib/admin/templates/admin/includes/fieldset.html

@@ -14,7 +14,7 @@
                     {% else %}
                         {{ field.label_tag }}
                         {% if field.is_readonly %}
-                            <p>{{ field.contents }}</p>
+                            <p>{{ field.contents|linebreaksbr }}</p>
                         {% else %}
                             {{ field.field }}
                         {% endif %}

tests/regressiontests/admin_views/admin.py

@@ -388,7 +388,10 @@ class PrePopulatedPostAdmin(admin.ModelAdmin):
 
 class PostAdmin(admin.ModelAdmin):
     list_display = ['title', 'public']
-    readonly_fields = ('posted', 'awesomeness_level', 'coolness', 'value', lambda obj: "foo")
+    readonly_fields = (
+        'posted', 'awesomeness_level', 'coolness', 'value', 'multiline',
+        lambda obj: "foo"
+    )
 
     inlines = [
         LinkInline
@@ -402,6 +405,10 @@ class PostAdmin(admin.ModelAdmin):
 
     def value(self, instance):
         return 1000
+
+    def multiline(self, instance):
+        return "Multiline\ntest\nstring"
+
     value.short_description = 'Value in $US'
 
 

tests/regressiontests/admin_views/tests.py

@@ -3149,6 +3149,10 @@ class ReadonlyTest(TestCase):
         self.assertContains(response, "Very awesome.")
         self.assertContains(response, "Unkown coolness.")
         self.assertContains(response, "foo")
+
+        # Checks that multiline text in a readonly field gets <br /> tags
+        self.assertContains(response, "Multiline<br />test<br />string")
+
         self.assertContains(response,
             formats.localize(datetime.date.today() - datetime.timedelta(days=7))
         )