  “We must minimize the need to change existing code. For adoption in existing code, decades of experience has consistently shown that most customers with large code bases cannot and will not change even 1% of their lines of code in order to satisfy strictness rules, not even for safety reasons unless regulatory requirements compel them to do so.” – Herb Sutter

  with large code bases cannot and will not change even 1% of their lines of code in order to satisfy strictness rules

Do people really say this? Voice this in committee? I have been in a few companies, and one fairly large one, and all are happy to and looking forward to upgrade newer standards and already spend a lot of time updating their build systems. Changing 1% of code on top of that is probably not really that much compared

▲ loup-vaillant 2 years ago | parent | next [-]

> Changing 1% of code on top of that is probably not really that much compared

Quite a few companies have millions and millions of lines of code. Changing 1% of it would mean changing more than 10K lines of code, perhaps even more than 100K. In much bigger code bases, where changing anything has a risk of breaking something — not just because you might make a mistake, but because your program is full of Undefined Behaviour, and changing anything might manifest latent bugs.

Given that, I'm not surprised people say that Sutter quote with a straight face.

▲ bregma 2 years ago | parent | prev | next [-]

Many of my customers are in an industry with a huge C++ code base and it's all under active development. Safety certification requirements are onerous and lead-times for development are long: many are now experimenting with C++17 and C++20 is on the long-term horizon but not yet a requirement. Because of the safety certification requirements and the fact that the expected lifecycle of the software is the order of decades after their products have been released, changing any lines of their code for any reason is always risky. Lives can be at stake.

But this is a multi-billion-dollar industry. If you're working on scripting a little browser "app" for a phone things may be different.

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titanomachy 2 years ago | parent | next [-]

“Little browser apps for phones” are a trillion-dollar industry

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nicce 2 years ago | parent | prev [-]

Is there a lot of manual work for getting the new certificate? E.g. is human rewiewing the code? If not, someone should build CI pipeline for the certification process.

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bluGill 2 years ago | parent [-]

Hundreds of hours of manual testing. I don't have to do safety certificates, but my code gets 500 hours of manual testing (I'm not allowed to give real numbers, these numbers are close enough) - they find enough critical can't ship issues where the fix is risky enough to start all over that we typically are doing 2500 hours of manual testing. on every release.

We have a large automated test suite that runs on every build and takes hours. The problem with automated tests is they only verify situations you thought of work the way you think they should, while human testers find slight variations of setup that you wouldn't think matter until they do. Human tests also find cases where the way you expect things to work don't make sense in the real world.

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bregma 2 years ago | parent [-]

Wait until you find out about the cat test. It found a failure mode no human had thought of. No amount of the developer claiming a test like that was not fair was enough to invalidate the results. No actual cats were harmed but treats may have been given.

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ModernMech 2 years ago | parent [-]

Do you have more context? I'm having trouble googling what you're referencing.

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noisy_boy 2 years ago | parent [-]

Simulate a cat walking on the keyboard to handle weird inputs?

	▲	ModernMech 2 years ago \| parent [-]
		Isn't that just fuzzing? I thought maybe there was a specific thing called the cat test.

▲ rwmj 2 years ago | parent | prev [-]

People just don't make mass changes to existing working code. Mostly they cannot. Even if the tooling was available, which it's not, it's also about reeducating their developers, who don't want to or can't change. Plus it'd have to be recertified. It's all cost with no benefit.

Except, allegedly, at Google. But is there any evidence they actually do this, eg. in public code bases? Or is it just hype?

	▲	j16sdiz 2 years ago \| parent [-]
		Google do this to their internal monorepo. This is one of the reason why they are bad at open sourcing - their internal code almost never match what is released