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Joined 1 year ago
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Cake day: August 13th, 2023

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  • I personally factorize as soon as there are two copies, but do not hesitate to inline the code and redo the abstraction when there is a 3rd use if it doesn’t fit. I find it much easier to inline and re-abstact a bad abstraction, than check if two copies are indeed identical.

    The exception is business logic. Usually I want all of them to be dupplicates because there is a very high chance that it’s just accidental that part of the logic is similar. I take great care to have good primitives but the actual business logic that glue those primitives together is written as many time as needed.


  • First experience with #jj #jujitsu

    I tried the equivalent of git add -p (jj squash -i).

    • I realize that it’s closer to git add --interactive (which I find much more complicated and less productive)
    • I wasn’t able to edit a hunk (like the e key in git add -p) which I use a lot to split debug statements from real work

    I generated a conflict (as I expected)

    • I found no way to show the original diff
    • jj undo did not worked (I have not been able to undo the jj squash that introduced the conflict

    Very not impressed so far. Fortunately it was a test repo.





  • I think you have a hard time understanding the différence between “not possible” and “much harder”.

    In Rust, the code does not compile.

    In C++ the code compile, but

    • if you have a test case
    • this test case triggers the bug (it is not guarateed to properly reproduce you production environment since it depends on the parameters of the allocator of your vector)
    • you use ubsan

    … then the bug will be caught.

    Yes it is possible, noone says the opposite. But you can’t deny it’s harder. And because its harder, more bugs get past review, most notably security bugs as demonstrated again and again in many studies. The


  • That’s why I did not said it was impossible, just order of magnitude harder to catch in C++ compared to Rust.

    To have asan finding the bug, you need to have a valid unit test, that has a similar enough workload. Otherwise you may not see the bug with asan if the vector doesn’t grow (and thus ref would still be valid, not triggering UB), leading to a production-only bug.

    Asan is a wonderfull tool, but you can’t deny it’s much harder to use and much less reliable than just running your compiler.


  • void foo() {
        std::vector v = {0, 1, 2, 4};
        const auto& ref = v[1];
        add_missing_values(v);
        std::cout << ref << "\n";
    }
    
    void add_missing_values(std::vector<int>& v) {
        // ...
        v.push_back(3);
    }
    

    Neither foo(), nor add_missing_values() looks suspicious. Nonetheless, if v.push_back(3) requires v to grow, then ref becomes an invalid reference and std::cout << ref becomes UB (use after free). In Rust this would not compiles.

    It is order of magnitudes easier to have lifetime errors in C++ than in Rust (use after free, double free, data races, use before initialisation, …)














  • robinmtoProgrammingisBooleanTooLongAndComplex
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    8 months ago

    I absolutely agree that method extraction can be abused. One should not forget that locality is important. Functionnal idioms do help to minimise the layer of intermediate functions. Lamda/closure helps too by having the function much closer to its use site. And local variables can sometime be a better choice than having a function that return just an expression.