Ramsay Jones wrote:
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> Josh Triplett wrote:
>> Ramsay Jones wrote:
>>> fix most of those problems. (the output from "make check" was about 1=
6k
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>>> lines at one point!). Git also tickled a bug in sparse 0.2, which res=
ulted
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>>> in some 120+ lines of bogus warnings; that was fixed in version 0.3 (=
commit
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>>> 0.2-15-gef25961).  As a result, sparse version 0.3 + my patches, elic=
its 106
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>>> lines of output from "make check".
>> One note about using Sparse with Git: you almost certainly don't want =
to pass
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>> -Wall to sparse, and current Git passes CFLAGS to Sparse which will do=
 exactly
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>> that.  -Wall turns on all possible Sparse warnings, including nitpicky=

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>> warnings and warnings with a high false positive rate.
>=20
> I have to say that, my initial reaction, was to disagree; I certainly w=
ant to
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> pass -Wall to sparse! Why not? Did you have any particular warnings in =
mind?
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> (I haven't noticed any that were nitpicky or had a high false positive =
rate!)

If you don't mind the set of warnings you get, then sure, use -Wall.

Some of the ones I had in mind:
* -Wshadow.  Not everyone cares.
* -Wptr-subtraction-blows.  This warns any time you do ptr2 - ptr1.
* -Wundefined-preprocessor.  This warns if you ever do
  #if SYMBOL
  when SYMBOL might not actually have a definition.  Many projects do exa=
ctly
  that, and the C standard allows it.
* -Wtypesign.  Off by default for the same reason that GCC doesn't give s=
ign
   mismatches by default: too many codebases with too many sloppy signedn=
ess
   issues that drown out other issues.

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> ...  You should start from
>> the default set of Sparse warnings, and add additional warnings as des=
ired, or
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>> turn off those you absolutely can't live with. =20
>=20
> Why not "-Wall -Wno-nitpicky -Wno-false-positive" ;-)

If you don't mind that, then sure.  You might have to adjust the warning =
list
to taste from time to time.  But please do use -Wall if you feel comforta=
ble
with the warnings it produces.

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> ... Current Sparse from Git (post
>> 0.3, after commit e18c1014449adf42520daa9d3e53f78a3d98da34) has a chan=
ge to
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>> cgcc to filter out -Wall, so you can pass -Wall to GCC but not Sparse.=
 =20
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>=20
> Yes, I noticed that. Again, I'm not sure I agree.
> I didn't comment on that patch, because my exposure to sparse is very l=
imited.
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> So far I've only run it on git, so I can hardly claim any great experie=
nce with
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> the output from sparse. However, 105 lines of output (which represents =
71 warnings)
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> for 72,974 lines of C (in 179 .c files) did not seem at all unreasonabl=
e.

True; for a project the size of Git, you can reasonably handle all the
warnings as you did.

If you want to use -Wall with sparse, you can always pass -Wall to sparse=

directly, or use CHECK=3D"sparse -Wall" cgcc. =20

- Josh Triplett