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`three = 1` in the Linux sourcecode (2014)

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Re: `three = 1` in the Linux sourcecode (2014)

#31

Post by tremon »

scotty79 wrote: post #12
ronyeh wrote: post #11

Earlier quoted context omitted.

I see a problem: https://github.com/torvalds/linux/blob/master/fs/ext4/resize... Upon a quick code review, these lines look buggy: unsigned three = 1; unsigned five = 5; unsigned seven = 7; Without digging deeper, the reader of this code thinks "The first line surely must be a bug, right???"

Not really. Nobody sane would think other sane developer with any expeirience would call a simple variable according to what it initially contains. You'd expect either name related to what is the meaning of the contents, or meaningless name.

When

  unsigned three = 1;
is accompanied by

  unsigned five = 5;
  unsigned seven = 7;
what would be the sane conclusion?

Re: `three = 1` in the Linux sourcecode (2014)

#32

Post by esrauch »

forgottenlogin9 wrote: post #30
scotty79 wrote: post #27

Earlier quoted context omitted.

True. But the intention of writing int three = 3; is insane. I would never ascribe to previous programmer (unless he just learned what variables are) the intention of creating variable (not even constant, which wouldn't make it any better) named 'three' and assigning actual value 3 to it.

If that is insane, you may not have issue with this specific line but you surely have issue with the 2 “insane” lines that follow it?

All three lines would be "insane" if the variables weren't mutated. As in a variable named "three" is insane if it solely contains either of the values 1 or 3.

When it contains other values it is still subpar variable naming.

Re: `three = 1` in the Linux sourcecode (2014)

#36

Post by CWuestefeld »

Many years ago in an age of klocs and flowcharts, at a large three-letter computer company, there were iron-clad coding rules that must be obeyed, no questions allowed. In general you could see their reasoning, but such bureaucratic reasoning doesn't pay off.

One example of this was that all numeric values used in a program must be factored out as symbolic constants. The reason for doing this is obvious, but it failed to account for the fact that some numbers have intrinsic meaning that should allow their use directly. But to be compliant with the standard, our C code had this boilerplate up near the top:

  #define zero 0
  #define one  1
This, of course, only served to make every page of code harder to read. And it didn't really even solve the problem it was meant to. We once found in some source code:

  #define thirteen 13
which of course did nothing to show us why that particular value was relevant.

Re: `three = 1` in the Linux sourcecode (2014)

#37

Post by kortex »

ben_w wrote: post #29
kortex wrote: post #26

Earlier quoted context omitted.

unsigned three = 1; To me, that is a 20 foot tall neon orange flashing Chesterton's fence. I think, "surely there is a very strong reason for this." Maybe not a good reason, but definitely a compelling one.

If I was code reviewing this, I would almost certainly insist on a different name to make the WTF go away. I’m not going to suggest one here despite having read the other code comment, as doing so would be bikeshedding — not my codebase and I have no skin in this — the only point I will insist on is that I cannot believe that “three” is a sensible choice of name for whatever it does. Not even what the comment implies…

Totally agree, it would definitely be better to rename it, but I read in another comment that the kernel is loathe to rename things. So then it makes you wonder, who allowed 'number_noun = N' in the first place?

"Three is the number of the counting, and the number thou shalt count to is three"

Re: `three = 1` in the Linux sourcecode (2014)

#38

Post by wycy »

CWuestefeld wrote: post #36

Many years ago in an age of klocs and flowcharts, at a large three-letter computer company, there were iron-clad coding rules that must be obeyed, no questions allowed. In general you could see their reasoning, but such bureaucratic reasoning doesn't pay off. One example of this was that all numeric values used in a program must be factored out as symbolic constants. The reason for doing this is obvious, but it faile…

We have something similar in my my organization's Fortran code. We have constants KI1, KI2, KI3, ... etc corresponding to (k)onstant integers 1, 2, 3, ... etc. Someone got the idea that hard-coded numbers were bad. All it does is make code harder to read to anyone unfamiliar with these conventions.

Re: `three = 1` in the Linux sourcecode (2014)

#39

Post by hannasanarion »

CWuestefeld wrote: post #36

Many years ago in an age of klocs and flowcharts, at a large three-letter computer company, there were iron-clad coding rules that must be obeyed, no questions allowed. In general you could see their reasoning, but such bureaucratic reasoning doesn't pay off. One example of this was that all numeric values used in a program must be factored out as symbolic constants. The reason for doing this is obvious, but it faile…

Why is the reason for doing this obvious? I can't see any benefit.

I get why you would prefer to name constants for their use, like `numIterations=3` or whatever, but renaming every integer seems senseless.

Re: `three = 1` in the Linux sourcecode (2014)

#40

Post by megous »

tremon wrote: post #31
scotty79 wrote: post #12

Earlier quoted context omitted.

Not really. Nobody sane would think other sane developer with any expeirience would call a simple variable according to what it initially contains. You'd expect either name related to what is the meaning of the contents, or meaningless name.

When unsigned three = 1; is accompanied by unsigned five = 5; unsigned seven = 7; what would be the sane conclusion?

These are variables that will change anyway, so the initial values are probably not that relevant to their name?
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