zeekayandYakov Olkhovskiy 23723e273c Tighten fuzzer arguments to reduce false-positive NightlyFuzzers failures
The NightlyFuzzers job has been failing every night for the past 2+ weeks
due to two fuzzers hitting libFuzzer's timeout and RSS limits with inputs
that are not genuine bugs.

`create_parser_fuzzer`: timeout (20-29s vs 20s limit) in 10/14 nights.
Caused by expensive `ParserCreateQuery` 5-way disjunction and large ASTs
being formatted via `formatWithSecretsOneLine`. Add `max_parser_depth=50`,
`max_ast_depth=200`, `max_ast_elements=10000`, and reduce
`max_parser_backtracks` from 10000 to 7000. These cause the parser/AST
checks to throw exceptions (caught by the fuzzer) instead of running for
20+ seconds.

`data_type_deserialization_fuzzer`: OOM (4100-4500 MB vs 4096 MB limit) in
14/14 nights. Root causes: nested `Array` types with `max_parser_depth=100`
allow multiplicative element explosion during deserialization; Object/JSON
`max_object_size` was left at default 100000; MemoryTracker at 1 GiB maps
to ~3-4 GiB RSS under ASan. Reduce `max_parser_depth` from 100 to 20, add
configurable `max_object_size` (set to 100) and `memory_limit` (set to
512 MiB) as new fuzzer arguments wired through C++ code.

Co-authored-by: Yakov Olkhovskiy <[email protected]>
2026-06-11 17:25:34 +00:00
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