Fixed a regression such that if you set .hidden on a tag, the tag

  becomes invisible but its contents are still visible. User manipulation
  of .hidden is not a documented or supported feature, so don't do this,
  but it's not too difficult to keep the old behavior working.

3 files changed, 25 insertions, 0 deletions

diff --git a/CHANGELOG b/CHANGELOG
index f6a7258..94f1209 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -1,3 +1,10 @@
+= 4.12.3 (?)
+
+* Fixed a regression such that if you set .hidden on a tag, the tag
+  becomes invisible but its contents are still visible. User manipulation
+  of .hidden is not a documented or supported feature, so don't do this,
+  but it's not too difficult to keep the old behavior working.
+
 = 4.12.2 (20230407)
 
 * Fixed an unhandled exception in BeautifulSoup.decode_contents
diff --git a/bs4/element.py b/bs4/element.py
index 33cbc19..0aefe73 100644
--- a/bs4/element.py
+++ b/bs4/element.py
@@ -1845,6 +1845,11 @@ class Tag(PageElement):
         return space_before + s + space_after
 
     def _format_tag(self, eventual_encoding, formatter, opening):
+        if self.hidden:
+            # A hidden tag is invisible, although its contents
+            # are visible.
+            return ''
+
         # A tag starts with the < character (see below).
 
         # Then the / character, if this is a closing tag.
diff --git a/bs4/tests/test_tag.py b/bs4/tests/test_tag.py
index 88cc202..c48f334 100644
--- a/bs4/tests/test_tag.py
+++ b/bs4/tests/test_tag.py
@@ -219,3 +219,16 @@ class TestMultiValuedAttributes(SoupTest):
         )
         assert soup.a['class'] == 'foo'
         assert soup.a['id'] == ['bar']
+
+    def test_hidden_tag_is_invisible(self):
+        # Setting .hidden on a tag makes it invisible in output, but
+        # leaves its contents visible.
+        #
+        # This is not a documented or supported feature of Beautiful
+        # Soup (e.g. NavigableString doesn't support .hidden even
+        # though it could), but some people use it and it's not
+        # hurting anything to verify that it keeps working.
+        #
+        soup = self.soup('<div id="1"><span id="2">a string</span></div>')
+        soup.span.hidden = True
+        assert '<div id="1">a string</div>' == str(soup.div)