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This didn't age very well. Especially the part celebrating "over-engineering" including the explicit duplication of code, instead of re-use, since that is "risk

by tpmx 6y ago

This didn't age very well. Especially the part celebrating "over-engineering" including the explicit duplication of code, instead of re-use, since that is "risky". I do however like the strong emphasis on (manual) testing.

Jtsummers 6y ago
That section actually criticizes duplication, it does not endorse it: > So it seems safer to take an entirely fresh copy of the existing code, and modify that instead. Over a period of years there arise a whole family of such near-clones, extending over several generations. Each of them is a quick and efficient solution to an immediate problem; but over time they create additional problems of maintenance of the large volumes of code. For example, if a change is made in one version of the clone, it is quite difficult even to decide whether it should be propagated to the other versions, so it usually isn't. The expense arises when the same error or deficiency has to be detected and corrected again in the other versions. Note his use of the phrase "it seems safer", he doesn't say it is safer and at the end explains what the actual risk/expense is with the copy/paste approach. And at the end he discusses the issues with over-engineering in summary: > The limitation of over-engineering as a safety technique is that the extra weight and volume may begin to contribute to the very problem that it was intended to solve. No-one knows how much of the volume of code of a large system is due to over-engineering, or how much this costs in terms of reliability. In general safety engineering, it is not unknown for catastrophes to be caused by the very measures that are introduced to avoid them.
jpollock 6y ago
Code reuse can result in failures. Sometimes those failures are big and loud. The Ariane 5 failure also happened in 1996, which is quite funny. :) https://www.bugsnag.com/blog/bug-day-ariane-5-disaster https://www.bugsnag.com/blog/bug-day-ariane-5-disaster https://www.youtube.com/watch?v=gp_D8r-2hwk https://www.youtube.com/watch?v=gp_D8r-2hwk

by tpmx 6y ago

Jtsummers 6y ago

That section actually criticizes duplication, it does not endorse it: > So it seems safer to take an entirely fresh copy of the existing code, and modify that instead. Over a period of years there arise a whole family of such near-clones, extending over several generations. Each of them is a quick and efficient solution to an immediate problem; but over time they create additional problems of maintenance of the large volumes of code. For example, if a change is made in one version of the clone, it is quite difficult even to decide whether it should be propagated to the other versions, so it usually isn't. The expense arises when the same error or deficiency has to be detected and corrected again in the other versions. Note his use of the phrase "it seems safer", he doesn't say it is safer and at the end explains what the actual risk/expense is with the copy/paste approach. And at the end he discusses the issues with over-engineering in summary: > The limitation of over-engineering as a safety technique is that the extra weight and volume may begin to contribute to the very problem that it was intended to solve. No-one knows how much of the volume of code of a large system is due to over-engineering, or how much this costs in terms of reliability. In general safety engineering, it is not unknown for catastrophes to be caused by the very measures that are introduced to avoid them.

jpollock 6y ago

Code reuse can result in failures. Sometimes those failures are big and loud. The Ariane 5 failure also happened in 1996, which is quite funny. :) https://www.bugsnag.com/blog/bug-day-ariane-5-disaster https://www.bugsnag.com/blog/bug-day-ariane-5-disaster https://www.youtube.com/watch?v=gp_D8r-2hwk https://www.youtube.com/watch?v=gp_D8r-2hwk