AST fuzzer: Fix assertion in TopK serialization#48412
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Problem: https://s3.amazonaws.com/clickhouse-test-reports/0/fa5b2bd4a5b02336bca8837c473a7124f8ecedf2/fuzzer_astfuzzerasan/report.html The new assertion in the Varint code was introduced with (*). It rejects values whose serialization cannot be deserialized (and this behavior cannot be changed due to historical reasons). Such values should be exceptionally rare in practice but AST fuzzer managers to trigger them. The fix is similar to (**): Bypass the check by limiting the value to the maximum allowed value. (if AST fuzzer triggers finds more violations of the assertion, we might consider throwing an exception instead) (*) #48154 (**) https://github.com/ClickHouse/ClickHouse/pull/48154/files#diff-653c0a18dfdaa86262c78dc6b25550add0487f165b4ad053e86f530388f6203a
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PR #48154 introduced a sanity check in the form of a debug assertion that the input values for VarInt encoding are not too big. Such values should be exceptionally rare in practice but the AST fuzzer managed to trigger the assertion regardless. The strategy to deal with such values until now was to bypass the check by limiting the value to the maximum allowed value (see #48412). Because a new AST Fuzzer failure appeared (#48497) and there may be more failures in future, this PR changes the sanity check from an assert to an exception. Fixes: #48497
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Problem:
https://s3.amazonaws.com/clickhouse-test-reports/0/fa5b2bd4a5b02336bca8837c473a7124f8ecedf2/fuzzer_astfuzzerasan/report.html
The new assertion in the Varint code was introduced with #48154. It rejects values whose serialization cannot be deserialized (and this behavior cannot be changed due to historical reasons). Such values should be exceptionally rare in practice but AST fuzzer managers to trigger them.
The fix is similar to this fix: Bypass the check by limiting the value to the maximum allowed value.
(if AST fuzzer triggers finds more violations of the assertion, we might consider throwing an exception instead)
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