[core] utils: fix get_element_by_*

test/test_utils.py

@@ -1769,6 +1769,10 @@ Line 1
         <div itemprop="author" itemscope>foo</div>
     '''
 
+    GET_ELEMENT_BY_ATTRIBUTE_TEST_STRING_UPPERCASE = '''
+        <DIV itemprop="author" itemscope>foo</DIV>
+    '''
+
     def test_get_element_by_attribute(self):
         html = self.GET_ELEMENT_BY_CLASS_TEST_STRING
 
@@ -1780,6 +1784,10 @@ Line 1
 
         self.assertEqual(get_element_by_attribute('itemprop', 'author', html), 'foo')
 
+        html = self.GET_ELEMENT_BY_ATTRIBUTE_TEST_STRING_UPPERCASE
+
+        self.assertEqual(get_element_by_attribute('itemprop', 'author', html), 'foo')
+
     def test_get_element_html_by_attribute(self):
         html = self.GET_ELEMENT_BY_CLASS_TEST_STRING
 
@@ -1851,6 +1859,11 @@ Line 1
     GET_ELEMENT_BY_TAG_RES_INNERSPAN_HTML = GET_ELEMENT_BY_TAG_TEST_STRING.strip()[78:119]
     GET_ELEMENT_BY_TAG_RES_INNERSPAN_TEXT = GET_ELEMENT_BY_TAG_RES_INNERSPAN_HTML[6:-7]
 
+
+    GET_ELEMENT_BY_TAG_TEST_STRING_UPPERCASE = '''
+        <SPAN id="foo">nice</SPAN>
+    '''
+
     def test_get_element_text_and_html_by_tag(self):
         html = self.GET_ELEMENT_BY_TAG_TEST_STRING
 
@@ -1860,8 +1873,15 @@ Line 1
         self.assertEqual(
             get_element_text_and_html_by_tag('span', html),
             (self.GET_ELEMENT_BY_TAG_RES_INNERSPAN_TEXT, self.GET_ELEMENT_BY_TAG_RES_INNERSPAN_HTML))
+
         self.assertRaises(compat_HTMLParseError, get_element_text_and_html_by_tag, 'article', html)
 
+        html = self.GET_ELEMENT_BY_TAG_TEST_STRING_UPPERCASE
+
+        self.assertEqual(
+            get_element_text_and_html_by_tag('SPAN', html),
+            ('nice', html.strip()), html)
+
     def test_iri_to_uri(self):
         self.assertEqual(
             iri_to_uri('https://www.google.com/search?q=foo&ie=utf-8&oe=utf-8&client=firefox-b'),

yt_dlp/utils/_utils.py

@@ -442,7 +442,7 @@ def get_element_text_and_html_by_tag(tag, html):
     content_start += whole_start + 1
     with HTMLBreakOnClosingTagParser() as parser:
         parser.feed(html[whole_start:content_start])
-        if not parser.tagstack or parser.tagstack[0] != tag:
+        if not parser.tagstack or parser.tagstack[0] != tag.lower():
             raise compat_HTMLParseError(f'parser did not match opening {tag} tag')
         offset = content_start
         while offset < len(html):