On Mon, Jun 7, 2021 at 7:41 PM Bruno Haible <br...@clisp.org> wrote: > Hi Jim, > > > > > > @@ -183,6 +183,9 @@ main () > > > > > *(volatile int *) (page + 0x678) = 42; > > > > > break; > > > > > case 3: > > > > > +#if 6 < __GNUC__ > > > > > +# pragma GCC diagnostic ignored "-Wnull-dereference" > > > > > +#endif > > > > > *(volatile int *) 0 = 42; > > > > > break; > > > > > case 4: > > > > > > > > We shouldn't spend time eliminating warnings from test code. > > > > > > > > The goal is to have a good coverage of the lib/* code with unit tests. > > > > That means, we need to > > > > - make it easy to write unit tests, > > > > - not make it time-consuming to maintain them. > > > > > > > > Eliminating warnings from lib/* code is useful, to avoid bugs in the > > > > programs. But eliminating warnings from tests/* code goes against the > > > > goal of increasing test coverage. > > > > Hi Bruno, > > Isn't this code exceptional enough to merit three lines of warning > > suppression? > > No. Good unit tests do exceptional things, like calling close(-1), passing > NULL pointers to various functions, and other things that e.g. Coverity > warns about. > > > I would like to continue to use -Werror with most warning options even > > in test code, > > as long as the cost is low. This feels like a very low one-time cost. > > No, the cost is not low. Dmitry's patch also changed the linkage of 11 > functions. He did so to silence warnings (-Wmissing-prototypes) which are > 1) not part of '-Wall', > 2) just pointless for tests [my opinion as maintainer of most of these > tests]. > > I don't want the maintainers of packages that use Gnulib to push costs > onto Gnulib, when it is just for their personal preference. > > The tests in Gnulib are there to evaluate the reliability of Gnulib's > modules on a particular platform. The more test coverage we have, the > better. > > Warnings in the unit tests are not problems. Test *failures* are problems. > > gnulib-tool has options --with-tests and --tests-base, that allow a > package to ship the Gnulib tests and thus help Gnulib (by having more > people run the unit tests and report possible test failures). > > If a package maintainer insists on having warning-free builds, I kindly > ask them to not bundle the Gnulib tests any more — because requiring > warning-free tests from Gnulib is more of an impediment than of a help. > > For those package maintainers who are OK to accept warnings in the > Gnulib tests directory, on the other hand, I repeat my offer to > automatically add -Wno-error in the tests/Makefile.am of that directory.
I can live without -Wmissing-prototypes in gnulib tests, but I still remember times where using that option exposed a real bug. My point about the cost/benefit was regarding that 3-line addition for a single, deliberate NULL-deref. That one really does not deserve to quash -Wnull-dereference for all tests.
