locale("") gives 'collate_byname<char>::collate_byname failed to construct for ' on LO on mac #28
Description
The https://github.com/divvun/libreoffice-divvun extension built with libdivvun 0.3.3 crashes/hangs in LibreOffice on mac.
After compiling a debug build of LO we see the following output:
…
warn:linguistic:67283:363302:linguistic/source/gciterator.cxx:679: GrammarCheckingIterator::DequeueAndCheck ignoring N3com3sun4star3uno9ExceptionE msg: C++ code threw St13runtime_error: collate_byname<char>::collate_byname failed to construct for
…
warn:legacy.osl:67283:361460:sw/source/uibase/dialog/SwSpellDialogChildWindow.cxx:430: ApplyChangedSentence in initial call or after resume
Running that through lldb (make debugrun in LO) and fiddling with breakpoints (first b linguistic/source/gciterator.cxx:607, c, then break set -E cxx and c; bt; c; bt …), we see that the error thrown is
thread #18, name = 'GrammarCheckingIterator', stop reason = breakpoint 2.2
frame #0: 0x00007fff7767d80b libc++abi.dylib`__cxa_rethrow
libc++abi.dylib`__cxa_rethrow:
-> 0x7fff7767d80b <+0>: pushq %rbp
0x7fff7767d80c <+1>: movq %rsp, %rbp
0x7fff7767d80f <+4>: pushq %r15
0x7fff7767d811 <+6>: pushq %r14
Target 0: (soffice) stopped.
(lldb) bt
* thread #18, name = 'GrammarCheckingIterator', stop reason = breakpoint 2.2
* frame #0: 0x00007fff7767d80b libc++abi.dylib`__cxa_rethrow
frame #1: 0x00007fff77653ffe libc++.1.dylib`std::__1::locale::__imp::__imp(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&, unsigned long) + 2162
frame #2: 0x00007fff776553c8 libc++.1.dylib`std::__1::locale::locale(char const*) + 186
frame #3: 0x00000001763d8389 libdivvun.0.dylib`divvun::getCasing(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >) + 73
ie. the reason seems to be that in getCasing we call std::locale("") which then fails with collate_byname<char>::collate_byname failed to construct for .
But why does it work when running LO-bundled python-interpreter on the LO-extension from the command line? (And shouldn't the "" be a valid fallback locale?)