Fixed #19082 -- Enabled admin field pre-population for existing objects.

Thanks to msaelices and d1ffuz0r for the initial patch and tests.

3 files changed, 25 insertions, 20 deletions

diff --git a/django/contrib/admin/static/admin/js/prepopulate.js b/django/contrib/admin/static/admin/js/prepopulate.js
index 24f24f95a8..db7903a5ef 100644
--- a/django/contrib/admin/static/admin/js/prepopulate.js
+++ b/django/contrib/admin/static/admin/js/prepopulate.js
@@ -3,32 +3,37 @@
         /*
             Depends on urlify.js
             Populates a selected field with the values of the dependent fields,
-            URLifies and shortens the string. 
-            dependencies - array of dependent fields id's 
-            maxLength - maximum length of the URLify'd string 
+            URLifies and shortens the string.
+            dependencies - array of dependent fields ids
+            maxLength - maximum length of the URLify'd string
         */
         return this.each(function() {
-            var field = $(this);
-
-            field.data('_changed', false);
-            field.change(function() {
-                field.data('_changed', true);
-            });
+            var prepopulatedField = $(this);
 
             var populate = function () {
-                // Bail if the fields value has changed
-                if (field.data('_changed') == true) return;
- 
+                // Bail if the field's value has been changed by the user
+                if (prepopulatedField.data('_changed')) {
+                    return;
+                }
+
                 var values = [];
                 $.each(dependencies, function(i, field) {
-                  if ($(field).val().length > 0) {
-                      values.push($(field).val());
-                  }
-                })
-                field.val(URLify(values.join(' '), maxLength));
+                    field = $(field);
+                    if (field.val().length > 0) {
+                        values.push(field.val());
+                    }
+                });
+                prepopulatedField.val(URLify(values.join(' '), maxLength));
             };
 
-            $(dependencies.join(',')).keyup(populate).change(populate).focus(populate);
+            prepopulatedField.data('_changed', false);
+            prepopulatedField.change(function() {
+                prepopulatedField.data('_changed', true);
+            });
+
+            if (!prepopulatedField.val()) {
+                $(dependencies.join(',')).keyup(populate).change(populate).focus(populate);
+            }
         });
     };
 })(django.jQuery);
diff --git a/django/contrib/admin/static/admin/js/prepopulate.min.js b/django/contrib/admin/static/admin/js/prepopulate.min.js
index aa94937963..4a75827c97 100644
--- a/django/contrib/admin/static/admin/js/prepopulate.min.js
+++ b/django/contrib/admin/static/admin/js/prepopulate.min.js
@@ -1 +1 @@
-(function(a){a.fn.prepopulate=function(d,g){return this.each(function(){var b=a(this);b.data("_changed",false);b.change(function(){b.data("_changed",true)});var c=function(){if(b.data("_changed")!=true){var e=[];a.each(d,function(h,f){a(f).val().length>0&&e.push(a(f).val())});b.val(URLify(e.join(" "),g))}};a(d.join(",")).keyup(c).change(c).focus(c)})}})(django.jQuery);
+(function(b){b.fn.prepopulate=function(e,g){return this.each(function(){var a=b(this),d=function(){if(!a.data("_changed")){var f=[];b.each(e,function(h,c){c=b(c);c.val().length>0&&f.push(c.val())});a.val(URLify(f.join(" "),g))}};a.data("_changed",false);a.change(function(){a.data("_changed",true)});a.val()||b(e.join(",")).keyup(d).change(d).focus(d)})}})(django.jQuery);
diff --git a/django/contrib/admin/templatetags/admin_modify.py b/django/contrib/admin/templatetags/admin_modify.py
index 98ac1a657e..005bde3023 100644
--- a/django/contrib/admin/templatetags/admin_modify.py
+++ b/django/contrib/admin/templatetags/admin_modify.py
@@ -9,7 +9,7 @@ def prepopulated_fields_js(context):
     the prepopulated fields for both the admin form and inlines.
     """
     prepopulated_fields = []
-    if context['add'] and 'adminform' in context:
+    if 'adminform' in context:
         prepopulated_fields.extend(context['adminform'].prepopulated_fields)
     if 'inline_admin_formsets' in context:
         for inline_admin_formset in context['inline_admin_formsets']: