Fix premature chassert(analyzed_join.oneDisjunct()) for ASOF JOIN

[groeneai]

The AST fuzzer (amd_debug) reported a debug-build abort with stack
TreeRewriter::collectJoinedColumns -> abortOnFailedAssertion,
hash STID 2508-3d70, on queries shaped like:

SELECT * FROM t0 ASOF LEFT JOIN t1 ON and((t0.y > t1.y))

chassert(analyzed_join.oneDisjunct()) at TreeRewriter.cpp:759 also
asserts that the single clause is non-empty. For an ASOF JOIN whose ON
expression is a pure inequality (no equality key),
CollectJoinOnKeysVisitor records the ASOF keys into data.asof_*_key
but does NOT populate key_names_left / key_names_right. The clause stays
empty. In release builds the immediately-following any_keys_empty check
throws INVALID_JOIN_ON_EXPRESSION cleanly; the assertion was harmless
because assert was a no-op. After commit
445dafb5f098
converted assert to chassert, the assertion fires in debug builds
before the proper error can be thrown.

The shape produced by the fuzzer (and(...) around a single inequality) is
incidental — the same failure reproduces for the simpler ON t0.y > t1.y.

Fix: weaken to a count-only check, mirroring the OR branch immediately
above (line 753). Empty clauses for non-ASOF cases are still caught by
the existing any_keys_empty throw immediately below; ASOF clauses are
populated later by data.asofToJoinKeys.

Tested with clickhouse local (debug build, enable_analyzer = 0):

• Without fix: SIGABRT (exit 134) for both ON t0.y > t1.y and
  ON and((t0.y > t1.y)).
• With fix: both throw INVALID_JOIN_ON_EXPRESSION cleanly; proper ASOF
  JOINs with an equality + inequality continue to work.

Report:
https://s3.amazonaws.com/clickhouse-test-reports/json.html?REF=master&sha=13a9b8ea79c017e7e34c4b6065660398647e35f7&name_0=MasterCI&name_1=AST%20fuzzer%20%28amd_debug%29

No related open issue found.

Changelog category (leave one):

• CI Fix or Improvement (changelog entry is not required)

Changelog entry (a user-readable short description of the changes that goes into CHANGELOG.md):

Not for changelog: chassert only fires in debug / sanitizer builds; release behaviour is unchanged.

Documentation entry for user-facing changes

• Documentation is unchanged.

[groeneai]

Pre-PR validation gate (session cron:clickhouse-ci-task-worker:20260531-103000):

#	Gate	Status
a	Deterministic repro?	✅ clickhouse local --query "...ASOF LEFT JOIN... ON t0.y > t1.y SETTINGS enable_analyzer = 0" aborts (exit 134) every run in debug. Same for ON and((t0.y > t1.y)).
b	Root cause explained?	✅ chassert(analyzed_join.oneDisjunct()) requires !clauses.front().isEmpty(). For ASOF with a pure inequality, the visitor records keys into data.asof_*_key but the clause stays empty until asofToJoinKeys runs later (or any_keys_empty throws). Latent since 2021; surfaced after 445dafb5f098 converted assert → chassert.
c	Fix matches root cause?	✅ Weakened to count-only getClauses().size() == 1, mirroring the OR-branch (line 753). Emptiness for non-ASOF is still caught by the any_keys_empty throw immediately below.
d	Test intent preserved?	✅ Structural invariant ("exactly one disjunct after else-branch") still asserted. New stateless regression test (04303_asof_join_inequality_only_old_analyzer) covers both shapes (with and without and(...)) plus the proper ASOF sanity.
e	Both directions demonstrated?	✅ Without fix → SIGABRT 134, empty stdout, diff vs reference fails. With fix → exit 0, stdout matches reference exactly. Existing 00927_asof_*, 01428_nullable_asof_join still pass.
f	Fix is general?	✅ Single call site; the OR-branch sibling already uses the count-only form. No symmetric paths to widen.

[groeneai]

cc @vdimir @novikd — could you review this? It's a small fix to the old analyzer's TreeRewriter::collectJoinedColumns to keep a chassert from firing prematurely on ASOF joins with no equality key (AST-fuzzer-found STID 2508-3d70).

[clickhouse-gh]

Workflow [PR], commit [98619d6]

Summary: ❌

• Performance Comparison: Performance dashboard

job_name	test_name	status	info	comment
Stateless tests (amd_debug, distributed plan, s3 storage, parallel)		FAIL
	01090_zookeeper_mutations_and_insert_quorum_long	FAIL	cidb
Stateless tests (amd_tsan, s3 storage, parallel, 1/2)		FAIL
	Logical error: Bad cast from type A to B (STID: 3336-2f87)	FAIL	cidb, issue
Stress test (arm_ubsan)		FAIL
	Logical error: Coordination mode mismatch for stream A: got B, expected C (STID: 6117-726a)	FAIL	cidb

---

AI Review

Summary

This PR weakens the old analyzer's single-disjunct assertion in TreeRewriter::collectJoinedColumns so invalid pure-inequality ASOF JOIN clauses reach the existing INVALID_JOIN_ON_EXPRESSION path instead of tripping chassert first. The focused stateless regression covers both the simple and fuzzer-shaped invalid clauses plus a valid ASOF JOIN; I did not find any review findings.

Final Verdict

Status: ✅ Approve

[clickhouse-gh]

LLVM Coverage Report

Metric	Baseline	Current	Δ
Lines	84.40%	84.40%	+0.00%
Functions	91.40%	91.40%	+0.00%
Branches	77.00%	77.00%	+0.00%

Changed lines: Changed C/C++ lines covered by tests: 4/4 (100.00%) | Lost baseline coverage: none · Uncovered code

Full report · Diff report