If a search against each individual value of a multi-valued

  attribute fails, the search will be run one final time against the
  complete attribute value considered as a single string. [bug=1476868]

3 files changed, 33 insertions, 18 deletions

diff --git a/NEWS.txt b/NEWS.txt
index 73d737c..702623d 100644
--- a/NEWS.txt
+++ b/NEWS.txt
@@ -3,6 +3,16 @@
 * Beautiful Soup will now work with versions of html5lib greater than
   0.99999999. [bug=1603299]
 
+* If a search against each individual value of a multi-valued
+  attribute fails, the search will be run one final time against the
+  complete attribute value considered as a single string. That is, if
+  a tag has class="foo bar" and neither "foo" nor "bar" matches, but
+  "foo bar" does, the tag is now considered a match.
+
+  This happened in previous versions, but only when the value being
+  searched for was a string. Now it also works when searching for
+  regular expressions, lists of values, etc. [bug=1476868]
+
 * Fixed a bug that deranged the tree when a whitespace element was
   reparented into a tag that contained an identical whitespace
   element. [bug=1505351]
diff --git a/bs4/element.py b/bs4/element.py
index ad13533..5a3665e 100644
--- a/bs4/element.py
+++ b/bs4/element.py
@@ -1704,21 +1704,15 @@ class SoupStrainer(object):
         if isinstance(markup, list) or isinstance(markup, tuple):
             # This should only happen when searching a multi-valued attribute
             # like 'class'.
-            if (isinstance(match_against, unicode)
-                and ' ' in match_against):
-                # A bit of a special case. If they try to match "foo
-                # bar" on a multivalue attribute's value, only accept
-                # the literal value "foo bar"
-                #
-                # XXX This is going to be pretty slow because we keep
-                # splitting match_against. But it shouldn't come up
-                # too often.
-                return (whitespace_re.split(match_against) == markup)
-            else:
-                for item in markup:
-                    if self._matches(item, match_against):
-                        return True
-                return False
+            for item in markup:
+                if self._matches(item, match_against):
+                    return True
+            # We didn't match any particular value of the multivalue
+            # attribute, but maybe we match the attribute value when
+            # considered as a string.
+            if self._matches(' '.join(markup), match_against):
+                return True
+            return False
 
         if match_against is True:
             # True matches any non-None value.
diff --git a/bs4/tests/test_tree.py b/bs4/tests/test_tree.py
index 2f9aba1..6bcf8af 100644
--- a/bs4/tests/test_tree.py
+++ b/bs4/tests/test_tree.py
@@ -222,6 +222,17 @@ class TestFindAllByName(TreeTest):
         self.assertSelects(
             tree.find_all(id_matches_name), ["Match 1.", "Match 2."])
 
+    def test_find_with_multi_valued_attribute(self):
+        soup = self.soup(
+            "<div class='a b'>1</div><div class='a c'>2</div><div class='a d'>3</div>"
+        )
+        r1 = soup.find('div', 'a d');
+        r2 = soup.find('div', re.compile(r'a d'));
+        r3, r4 = soup.find_all('div', ['a b', 'a d']);
+        self.assertEqual('3', r1.string)
+        self.assertEqual('3', r2.string)
+        self.assertEqual('1', r3.string)
+        self.assertEqual('3', r4.string)
 
 class TestFindAllByAttribute(TreeTest):
 
@@ -294,10 +305,10 @@ class TestFindAllByAttribute(TreeTest):
         f = tree.find_all("gar", class_=re.compile("a"))
         self.assertSelects(f, ["Found it"])
 
-        # Since the class is not the string "foo bar", but the two
-        # strings "foo" and "bar", this will not find anything.
+        # If the search fails to match the individual strings "foo" and "bar",
+        # it will be tried against the combined string "foo bar".
         f = tree.find_all("gar", class_=re.compile("o b"))
-        self.assertSelects(f, [])
+        self.assertSelects(f, ["Found it"])
 
     def test_find_all_with_non_dictionary_for_attrs_finds_by_class(self):
         soup = self.soup("<a class='bar'>Found it</a>")