Don't anchor the aligned CASE indent on a missing END token - #942

Fixes #886.

AlignedIndentFilter._process_case appends a pseudo-case holding the END token so it can align it too, then uses that case's first token as the insert anchor:

end_token = tlist.token_next_by(m=(T.Keyword, 'END'))[1]
cases.append((None, [end_token]))
...
stmt = cond[0] if cond else value[0]
if i > 0:
    tlist.insert_before(stmt, self.nl(offset_ - len(str(stmt))))

token_next_by() returns (None, None) when the Case group has no END token of its own. That happens when the END is swallowed by a nested group:

>>> sqlparse.format("CASE 'a' := WHERE END SELECT GO # ->>", reindent_aligned=True)
ValueError: list.index(x): x not in list

>>> case = next(t for t in sqlparse.parse("CASE 'a' := WHERE END SELECT GO # ->>")[0].get_sublists())
>>> [(type(t).__name__, t.value) for t in case.tokens]
[('Token', 'CASE'), ('Token', ' '), ('Assignment', "'a' := WHERE END")]
>>> case.token_next_by(m=(T.Keyword, 'END'))
(None, None)

value[0] is then None, and insert_before(None) fails inside token_index().

Change

sqlparse/filters/aligned_indent.py: only append the END pseudo-case when an END token was actually found. There is nothing to align otherwise, so skipping it is correct rather than merely non-crashing.

Behaviour

Reported input now formats to itself instead of raising. Well-formed CASE alignment is untouched:

>>> print(sqlparse.format('SELECT CASE WHEN a=1 THEN 2 ELSE 3 END FROM t', reindent_aligned=True))
SELECT CASE WHEN a=1 THEN 2
            ELSE 3
             END
  FROM t

Tests

test_issue886_reindent_aligned_malformed_case in tests/test_regressions.py.

uv run --group dev pytest tests/
507 passed, 2 xfailed, 1 xpassed

uv run --group dev ruff check sqlparse/
All checks passed!

A CHANGELOG entry is added under Development Version.