From 0254f1627487c137abd201dea230247de6cb7f87 Mon Sep 17 00:00:00 2001
From: Zenon Mousmoulas <zmousm@users.noreply.github.com>
Date: Sun, 9 Jan 2022 20:14:56 +0200
Subject: [PATCH] [utils] Improve `get_elements_text_and_html_by_attribute`
 regex (#2280)

Authored by: zmousm, pukkandan
---
 test/test_utils.py |  6 +++---
 yt_dlp/utils.py    | 25 ++++++++++++-------------
 2 files changed, 15 insertions(+), 16 deletions(-)

diff --git a/test/test_utils.py b/test/test_utils.py
index c3ec798dc..2c8f2c03e 100644
--- a/test/test_utils.py
+++ b/test/test_utils.py
@@ -1659,10 +1659,10 @@ Line 1
         html = self.GET_ELEMENTS_BY_CLASS_TEST_STRING
 
         self.assertEqual(
-            get_elements_text_and_html_by_attribute('class', 'foo bar', html),
+            list(get_elements_text_and_html_by_attribute('class', 'foo bar', html)),
             list(zip(['nice', 'also nice'], self.GET_ELEMENTS_BY_CLASS_RES)))
-        self.assertEqual(get_elements_text_and_html_by_attribute('class', 'foo', html), [])
-        self.assertEqual(get_elements_text_and_html_by_attribute('class', 'no-such-foo', html), [])
+        self.assertEqual(list(get_elements_text_and_html_by_attribute('class', 'foo', html)), [])
+        self.assertEqual(list(get_elements_text_and_html_by_attribute('class', 'no-such-foo', html)), [])
 
     GET_ELEMENT_BY_TAG_TEST_STRING = '''
     random text lorem ipsum</p>
diff --git a/yt_dlp/utils.py b/yt_dlp/utils.py
index 826ab5d29..9a66de9f5 100644
--- a/yt_dlp/utils.py
+++ b/yt_dlp/utils.py
@@ -473,24 +473,23 @@ def get_elements_text_and_html_by_attribute(attribute, value, html, escape_value
     attribute in the passed HTML document
     """
 
+    value_quote_optional = '' if re.match(r'''[\s"'`=<>]''', value) else '?'
+
     value = re.escape(value) if escape_value else value
 
-    retlist = []
-    for m in re.finditer(r'''(?xs)
+    partial_element_re = r'''(?x)
         <(?P<tag>[a-zA-Z0-9:._-]+)
-         (?:\s+[a-zA-Z0-9_:.-]+(?:=\S*?|\s*=\s*(?:"[^"]*"|'[^']*')|))*?
-         \s+%(attribute)s(?:=%(value)s|\s*=\s*(?P<_q>['"]?)%(value)s(?P=_q))
-         (?:\s+[a-zA-Z0-9_:.-]+(?:=\S*?|\s*=\s*(?:"[^"]*"|'[^']*')|))*?
-        \s*>
-    ''' % {'attribute': re.escape(attribute), 'value': value}, html):
-        content, whole = get_element_text_and_html_by_tag(m.group('tag'), html[m.start():])
+         (?:\s(?:[^>"']|"[^"]*"|'[^']*')*)?
+         \s%(attribute)s\s*=\s*(?P<_q>['"]%(vqo)s)(?-x:%(value)s)(?P=_q)
+        ''' % {'attribute': re.escape(attribute), 'value': value, 'vqo': value_quote_optional}
 
-        retlist.append((
-            unescapeHTML(re.sub(r'(?s)^(?P<q>["\'])(?P<content>.*)(?P=q)$', r'\g<content>', content)),
-            whole,
-        ))
+    for m in re.finditer(partial_element_re, html):
+        content, whole = get_element_text_and_html_by_tag(m.group('tag'), html[m.start():])
 
-    return retlist
+        yield (
+            unescapeHTML(re.sub(r'^(?P<q>["\'])(?P<content>.*)(?P=q)$', r'\g<content>', content, flags=re.DOTALL)),
+            whole
+        )
 
 
 class HTMLBreakOnClosingTagParser(compat_HTMLParser):