c/tests: avoid ubsan signed integer overflow #24133
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Before the change ubsan would assert on a signed integer overflow ``` /vectorized/llvm/bin/../include/c++/v1/__chrono/duration.h:92:79: runtime error: signed integer overflow: 9223372036854775807 * 1000 cannot be represented in type '_Ct' (aka 'long long') cluster::tx::producer_state_manager::evict_excess_producers() at /vectorized/llvm/bin/../include/c++/v1/__chrono/duration.h:92 ``` The problem lies in that we try to subtract duration from a time_point with nanosecond granularity. When doing that, duration is converted to a common type, nanosecond representation and the millisecond::max() being already maximum value that can be represented in a long long can't be converted to micros (multiplied by 1000). Not sure if this is the perfect fix but avoid the problem by initializing the duration with a value that can be later represented as micros.
I'm probably missing something, if common_type(nanos, mills) = nanos, millis should be multiplied by 10^6, right? |
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Before the change ubsan would assert on a signed integer overflow
The problem lies in that we try to subtract duration from a time_point with nanosecond granularity. When doing that, duration is converted to a common type, nanosecond representation and the millisecond::max() being already maximum value that can be represented in a long long can't be converted to micros (multiplied by 1000).
Not sure if this is the perfect fix but avoid the problem by initializing the duration with a value that can be later represented as micros.
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