dev process - reduce mistakes

[Tobin C. Harding]

On Tue, Sep 18, 2018 at 08:01:22PM -0400, valdis.kletnieks at vt.edu wrote:
> On Wed, 19 Sep 2018 09:35:36 +1000, "Tobin C. Harding" said:
> > Hi,
> >
> > I'm after some advice from those more experienced with [kernel]
> > development please.
> >
> > What systems do you have in place to help catch mistakes?  In other
> > words; what processes do you use when coding and submitting patches to
> > help eliminate simple mistakes?
> 
> Same way you verify it for any other large programming project.
> 
> 'make clean && make && make install && shutdown -r now'
> 
> 1) Verify no compile errors.
> 
> 2) Verify no unexplained compile warnings. gcc *does* screw up and whine about
> things incorrectly on occasion because it doesn't know everything - "variable
> may be used uninitialized" is a famous one, usually emitted because there's
> program logic it can't see. For instance, code like:
> 
>     int oddball;
>     for (i=0;i<foo;i++) {
>          if (wombat > 5) oddball = 7;
>          if (frobozz) quux = oddball;
>     }
> 
> and there's a reason known to programmer but not compiler
> that guarantees that wombat > 5 will always happen at least once
> before frobozz becomes true.
> 
> But in general, unless you can *prove* the compiler is false-positive on
> a warning, fix the warning. ;)
> 
> 2a) (optional) Install 'sparse' and do a 'make C=2' and see if that complains about
> anything that gcc didn't...
> 
> 3) Test that it actually boots and does whatever your patch is supposed to do.
> 
> See? And here you thought it was difficult :)



Thanks for your response Valdis (especially the wombat reference).  I'm
talking though about more brain dead mistakes like:

- Muddling up changes between patches when rebasing
- Missing an instance of a series of the same changes (usually because
  you did 100 of them and one slipped past when viewing the diff)


Things that don't make the compiler or static analysis complain.  I made
an improvement on my method today and that was to review patch sets
[almost] ready for submission first thing in the day so your eyes/brain
is fresh.

These sort of 'soft' ideas I'm after please.  I'm sure the old fellas
have a bunch of them that they do unconsciously but any that any one can
think of would be great to hear.

thanks,
Tobin.