[BUG] ensure proper constexpr of string hashing fix fails to build on 32-bit archs

[brad0]

The fix(strutil.h): ensure proper constexpr of string hashing (#3901) commit fails to build on 32-bit archs.

3fd70cf

We noticed this with 2.4 but applies to 2.5 and newer. Reverting this commit alone and we're good building beyond 2.4.12 (upgrading from 2.4.11).

FAILED: src/libutil/CMakeFiles/strutil_test.dir/strutil_test.cpp.o
/pobj/openimageio-2.4.17.0/bin/c++ -DOIIO_INTERNAL=1 -DUSE_BOOST_FILESYSTEM -DUSE_EXTERNAL_PUGIXML=1 -DUSE_FREETYPE=1 -DUSE_JPEG_TURBO=1 -DUSE_OCIO=1 -DUSE_OPENCOLORIO=1 -D__STDC_CONSTANT_MACROS -D__STDC_LIMIT_MACROS -I/pobj/openimageio-2.4.17.0/build-i386/include/OpenImageIO -I/pobj/openimageio-2.4.17.0/build-i386/include -I/pobj/openimageio-2.4.17.0/build-i386/src/include -I/pobj/openimageio-2.4.17.0/OpenImageIO-2.4.17.0/src/include -isystem /usr/local/include -isystem /usr/local/include/Imath -O2 -pipe -DNDEBUG -std=c++14 -Wall -Wno-unused-function -Wno-overloaded-virtual -Wno-unneeded-internal-declaration -Wno-unused-private-field -Wno-tautological-compare -Qunused-arguments -Wunknown-warning-option -Wno-unused-local-typedefs -Wno-expansion-to-defined -fno-math-errno -MD -MT src/libutil/CMakeFiles/strutil_test.dir/strutil_test.cpp.o -MF src/libutil/CMakeFiles/strutil_test.dir/strutil_test.cpp.o.d -o src/libutil/CMakeFiles/strutil_test.dir/strutil_test.cpp.o -c /pobj/openimageio-2.4.17.0/OpenImageIO-2.4.17.0/src/libutil/strutil_test.cpp
/pobj/openimageio-2.4.17.0/OpenImageIO-2.4.17.0/src/libutil/strutil_test.cpp:354:22: error: constexpr variable 'hash' must be initialized by a constant expression
    constexpr size_t hash = Strutil::strhash("much longer string");
                     ^      ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/pobj/openimageio-2.4.17.0/OpenImageIO-2.4.17.0/src/include/OpenImageIO/detail/farmhash.h:1207:24: note: cannot refer to element -4 of array of 19 elements in a constant expression
  uint32_t a = Fetch(s - 4 + (len >> 1));
                       ^
/pobj/openimageio-2.4.17.0/OpenImageIO-2.4.17.0/src/include/OpenImageIO/detail/farmhash.h:1246:9: note: in call to 'Hash32Len13to24(&"much longer string"[0], 18, 0)'
        Hash32Len13to24(s, len);
        ^
/pobj/openimageio-2.4.17.0/OpenImageIO-2.4.17.0/src/include/OpenImageIO/detail/farmhash.h:2070:7: note: in call to 'Hash32(&"much longer string"[0], 18)'
      farmhashmk::Hash32(s, len));
      ^
/pobj/openimageio-2.4.17.0/OpenImageIO-2.4.17.0/src/include/OpenImageIO/detail/farmhash.h:2100:49: note: in call to 'Hash32(&"much longer string"[0], 18)'
  return sizeof(size_t) == 8 ? Hash64(s, len) : Hash32(s, len);
                                                ^
/pobj/openimageio-2.4.17.0/OpenImageIO-2.4.17.0/src/include/OpenImageIO/strutil.h:377:12: note: in call to 'Hash(&"much longer string"[0], 18)'
    return OIIO::farmhash::inlined::Hash(s, len);
           ^
/pobj/openimageio-2.4.17.0/OpenImageIO-2.4.17.0/src/include/OpenImageIO/strutil.h:389:25: note: in call to 'strhash(18, &"much longer string"[0])'
    return s.length() ? strhash(s.length(), s.data()) : 0;
                        ^
/pobj/openimageio-2.4.17.0/OpenImageIO-2.4.17.0/src/libutil/strutil_test.cpp:354:29: note: in call to 'strhash({&"much longer string"[0], 18})'
    constexpr size_t hash = Strutil::strhash("much longer string");
                            ^
1 error generated.

[lgritz]

Proposed fix posted as #4213

We're no longer routinely updating the 2.4 series of releases. But if this is important for you and you can't upgrade to 2.5, I can backport it to 2.4. Let me know.

[brad0]

Proposed fix posted as #4213

We're no longer routinely updating the 2.4 series of releases. But if this is important for you and you can't upgrade to 2.5, I can backport it to 2.4. Let me know.

We can upgrade. I was just pushing an update to 2.5.9 but then this was reported after my 2.4.17 update went in. I just want to at least get the root issue fixed first.

[brad0]

At least backport this to 2.5.

[lgritz]

At least backport this to 2.5.

Done. It will be in Monday's scheduled release.

[brad0]

Done. It will be in Monday's scheduled release.

Thanks.