support slice assignment on SafeBuffer

2 files changed, 38 insertions, 2 deletions

diff --git a/activesupport/lib/active_support/core_ext/string/output_safety.rb b/activesupport/lib/active_support/core_ext/string/output_safety.rb
index 3a80de4617..0b40c3d799 100644
--- a/activesupport/lib/active_support/core_ext/string/output_safety.rb
+++ b/activesupport/lib/active_support/core_ext/string/output_safety.rb
@@ -199,8 +199,12 @@ module ActiveSupport #:nodoc:
       super(html_escape_interpolated_argument(value))
     end
 
-    def []=(index, value)
-      super(index, html_escape_interpolated_argument(value))
+    def []=(*args)
+      if args.count == 3
+        super(args[0], args[1], html_escape_interpolated_argument(args[2]))
+      else
+        super(args[0], html_escape_interpolated_argument(args[1]))
+      end
     end
 
     def +(other)
diff --git a/activesupport/test/safe_buffer_test.rb b/activesupport/test/safe_buffer_test.rb
index 08d04e3223..32e1d2d5bf 100644
--- a/activesupport/test/safe_buffer_test.rb
+++ b/activesupport/test/safe_buffer_test.rb
@@ -112,6 +112,38 @@ class SafeBufferTest < ActiveSupport::TestCase
     end
   end
 
+  test "can assign value into zero-index" do
+    buffer = ActiveSupport::SafeBuffer.new("012345")
+
+    buffer[0] = "<"
+
+    assert_equal "&lt;12345", buffer
+  end
+
+  test "can assign value into non zero-index" do
+    buffer = ActiveSupport::SafeBuffer.new("012345")
+
+    buffer[2] = "<"
+
+    assert_equal "01&lt;345", buffer
+  end
+
+  test "can assign value into slice" do
+    buffer = ActiveSupport::SafeBuffer.new("012345")
+
+    buffer[0, 3] = "<"
+
+    assert_equal "&lt;345", buffer
+  end
+
+  test "can assign value into offset slice" do
+    buffer = ActiveSupport::SafeBuffer.new("012345")
+
+    buffer[1, 3] = "<"
+
+    assert_equal "0&lt;45", buffer
+  end
+
   test "Should escape dirty buffers on add" do
     clean = "hello".html_safe
     @buffer.gsub!("", "<>")