refactor: use more gsl::not_null in utils.h and deterministicmns.h#5651
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Please, review #5590 first |
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so far as this and many other places requires not-null anyway, why even don't change const CBlockIndex*> to the const CBlockIndex&` ?
For reference, couple PR with bitcoin's similar changes of CBlockIndex* to CBlockIndex&. Bitcoin doesn't change it everywhere, but only when it is obviously non-nullptr, such as:
https://github.com/bitcoin/bitcoin/pull/25677/files
https://github.com/bitcoin/bitcoin/pull/25016/files
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Well; so one benefit imo is that dereferencing a nullptr is undefined behavior not guaranteed to be caught at runtime; additionally, gsl::not_null doesn't require additional syntax to pass to a later func that needs a ptr or additional syntax when passing in a ptr. In bitcoin PR you mention it appears they force to use something like *Assert(m_chain.Tip() which is significantly more typing :D
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well, *Assert(...) is 7 bytes shorter than gsl::not_null<...>(...)
And indeed, you can avoid UB by validating it before converting to reference.
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Yeah; but *Assert you have to have at every call site instead of just function definition. They're both generally valid approaches imo
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yeah, but once you convert pointer to reference, you can assume that all recursive calls; submethods; helpers, etc are never have nullptr anymore; but for case of pointer - you need to add gsl:not_null to every method do show that is not nullptr.
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Well yes; same as every method needs to be declared as a reference. Once a not_null is constructed it is zero cost to pass it to another not_null function
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Issue being fixed or feature implemented
Use not_null if the function would crash if given a nullptr
What was done?
Refactored to use gsl::not_null
How Has This Been Tested?
Compiled
Breaking Changes
Should be none
Checklist:
Go over all the following points, and put an
xin all the boxes that apply.