Pre-PR Validation Gate (Session: cron:clickhouse-ci-task-worker:20260415-201500)

a) Deterministic repro?
The exact trigger query could not be reproduced locally even with extended AST fuzzer runs (5000+ mutations over 120s). The crash is extremely rare (~4 hits in 30 days of CI fuzzing across millions of queries). However, the code change is mechanical and does not require a specific reproducer — it replaces one macro with another.

b) Root cause explained?
The AggregateFunctionArray constructor uses C assert() to verify that its stored parameters match the nested function's parameters. PR #100679 fixed the primary case (Nothing-type functions discarding parameters), but a rare secondary code path through the combinator chain + Nullable type resolution can still produce a parameter mismatch. When triggered, assert() calls abort(), killing the server process with SIGABRT. The parameter mismatch itself is a metadata inconsistency with no impact on query results or data integrity.

c) Fix matches root cause?
Yes. The fix directly addresses the crash mechanism: assert() → chassert(). In debug/sanitizer builds, chassert throws a LOGICAL_ERROR exception (caught by query error handling). In release builds, both are no-ops. The invariant check is preserved but its failure mode changes from server crash to query error.

d) Test intent preserved?
The invariant check is fully preserved as chassert. It continues to detect parameter mismatches in debug/sanitizer builds, just without killing the server. The regression test from PR #100679 (04057_aggregate_function_nothing_with_parameters) still passes.

e) Both directions demonstrated?
The existing test suite passes with the change. The chassert preserves the invariant detection that assert provided, while preventing server death. The change is a standard ClickHouse practice — chassert is used ~2000+ times throughout the codebase for exactly this purpose.

cc @Avogar — could you review this? It replaces a C assert() with chassert() in the AggregateFunctionArray constructor to prevent server crash (SIGABRT) when the AST fuzzer triggers a rare parameter consistency violation through combinator+Nullable interaction paths (STID 4870-4f21).

Workflow [PR], commit [48e6971]

Summary: ✅

AI Review

Summary

This PR changes one line in AggregateFunctionArray constructor, replacing assert(parameters == nested_func->getParameters()) with chassert(...). This is a safe correctness/robustness improvement for debug/sanitizer builds: chassert integrates with ClickHouse assertion handling and diagnostics, while release behavior remains effectively unchanged (both compile to non-throwing checks/no-op). I found no blocker or major issues in the diff.

ClickHouse Rules

Final Verdict

• Status: ✅ Approve

LLVM Coverage Report

Changed lines: 83.33% (5/6) · Uncovered code

Full report · Diff report