Fix ValueError aligning a CASE with no END keyword

sqlparse/filters/aligned_indent.py

@@ -70,7 +70,11 @@ def _process_case(self, tlist):
         cases = tlist.get_cases(skip_ws=True)
         # align the end as well
         end_token = tlist.token_next_by(m=(T.Keyword, 'END'))[1]
-        cases.append((None, [end_token]))
+        # A malformed CASE (e.g. "case,end", which groups as an IdentifierList)
+        # has no standalone END keyword; skip the end alignment rather than
+        # appending a (None, [None]) entry that later crashes insert_before.
+        if end_token is not None:
+            cases.append((None, [end_token]))
 
         condition_width = [len(' '.join(map(str, cond))) if cond else 0
                            for cond, _ in cases]

tests/test_format.py

@@ -784,3 +784,14 @@ def test_strip_ws_removes_trailing_ws_in_groups():  # issue782
                                 strip_whitespace=True)
     expected = '(where foo = bar) from'
     assert formatted == expected
+
+
+def test_aligned_indent_case_without_end():
+    # A malformed CASE with no standalone END keyword (e.g. "case,end", which
+    # groups as an IdentifierList) must not crash the aligned-indent filter.
+    assert sqlparse.format('case,end', reindent_aligned=True) == 'case,end'
+    # A well-formed CASE is still aligned across its branches.
+    formatted = sqlparse.format(
+        'select case when 1 then 2 else 3 end from t', reindent_aligned=True)
+    assert 'when 1 then 2' in formatted
+    assert 'else 3' in formatted