On Wed, Jan 12, 2022 at 01:47:40PM +0100, Ævar Arnfjörð Bjarmason wrote:
> >> Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@xxxxxxxxx>
> >> ---
> >> reftable/refname.c | 1 -
> >> reftable/writer.c | 1 -
> >> 2 files changed, 2 deletions(-)
> >>
> >> diff --git a/reftable/refname.c b/reftable/refname.c
> >> index 95734969324..136001bc2c7 100644
> >> --- a/reftable/refname.c
> >> +++ b/reftable/refname.c
> >> @@ -132,7 +132,6 @@ static int validate_refname(const char *name)
> >> return REFTABLE_REFNAME_ERROR;
> >> name = next + 1;
> >> }
> >> - return 0;
> >> }
> >
> > In this case the loop inside of validate_refname() should always
> > terminate the function within the loop body. But removing this return
> > statement here relies on the compiler to determine that fact.
> >
> > I could well imagine on the other end of the spectrum there exists a
> > compiler which _doesn't_ make this inference pass, and would complain
> > about the opposite thing as you're reporting from SunCC (i.e., that this
> > function which returns something other than void does not have a return
> > statement outside of the loop).
> >
> > So in that sense, I disagree with the guidance of SunCC's warning. In
> > other words: by quelching this warning under one compiler, are we
> > introducing a new warning under a different/less advanced compiler?
>
> I'd think that any compiler who'd warn about this sort of thing at all
> would be able to spot constructs like this one, which are basically:
>
> while (1) {
> ...
> if (x)
> return;
> ...
> }
> return; /* unreachable */
>
> Where the elided code contains no "break", "goto" or other mechanism for
> exiting the for-loop.
>
> I.e. GCC and Clang don't bother to note the unreachable code, but I
> don't think the reverse will be true, that a compiler will say that a
> "return" is missing there. Having a function be just a loop body that
> returns an some point is a common pattern.
Right, but I'm more concerned about a less advanced compiler that would
complain about the absence of a `return` statement as the last
instruction in a non-void function.
This is probably all academic, anyway, since less advanced compilers
probably have other issues compiling Git as it stands today, but
fundamentally I think that SunCC's warnings here are at the very least
inconsiderate of less advanced compilers.
To me, the safest thing to do would be to leave the code as-is and drop
this patch.
Thanks,
Taylor
