Copying a NavigableString will give you a new NavigableString that is not connected to the parse tree.

3 files changed, 27 insertions, 1 deletions

diff --git a/NEWS.txt b/NEWS.txt
index 34d640c..6eeebd2 100644
--- a/NEWS.txt
+++ b/NEWS.txt
@@ -15,6 +15,10 @@ Especially important changes:
   argument described in the documentation. `text` may eventually
   change its meaning, but not for a very long time. [bug=1366856]
 
+* Changed the way soup objects work under copy.copy() and
+  copy.deepcopy(). Copying a NavigableString will give you a new
+  NavigableString that is not connected to the parse tree.
+
 * Started using a standard MIT license. [bug=1294662]
 
 * Added a Chinese translation of the documentation by Delong .w.
diff --git a/bs4/element.py b/bs4/element.py
index d1b7c12..0486da2 100644
--- a/bs4/element.py
+++ b/bs4/element.py
@@ -689,7 +689,10 @@ class NavigableString(unicode, PageElement):
         return u
 
     def __copy__(self):
-        return self
+        """A copy of a NavigableString has the same contents and class
+        as the original, but it is not connected to the parse tree.
+        """
+        return type(self)(self)
 
     def __getnewargs__(self):
         return (unicode(self),)
diff --git a/bs4/tests/test_tree.py b/bs4/tests/test_tree.py
index 7edf848..22d4b4f 100644
--- a/bs4/tests/test_tree.py
+++ b/bs4/tests/test_tree.py
@@ -1310,6 +1310,25 @@ class TestPersistence(SoupTest):
         loaded = pickle.loads(dumped)
         self.assertEqual(loaded.decode(), soup.decode())
 
+    def test_copy_navigablestring_is_not_attached_to_tree(self):
+        html = u"<b>Foo<a></a></b><b>Bar</b>"
+        soup = self.soup(html)
+        s1 = soup.find(string="Foo")
+        s2 = copy.copy(s1)
+        self.assertEqual(s1, s2)
+        self.assertEqual(None, s2.parent)
+        self.assertEqual(None, s2.next_element)
+        self.assertNotEqual(None, s1.next_sibling)
+        self.assertEqual(None, s2.next_sibling)
+        self.assertEqual(None, s2.previous_element)
+
+    def test_copy_navigablestring_subclass_has_same_type(self):
+        html = u"<b><!--Foo--></b>"
+        soup = self.soup(html)
+        s1 = soup.string
+        s2 = copy.copy(s1)
+        self.assertEqual(s1, s2)
+        self.assertTrue(isinstance(s2, Comment))
 
 class TestSubstitutions(SoupTest):