exiv2 0.27+ on darwin fails with Exiv2::BasicError<char> error

[samm-git]

Hi,

After upgrade from 0.26 to 0.27 on darwin i am getting following error

libc++abi.dylib: terminating with uncaught exception of type Exiv2::BasicError<char>: No namespace info available for XMP prefix `DICOM'

This is part of the trace, issue is triggered when app is calling gexiv2_metadata_register_xmp_namespace

  * frame #0: 0x00007fff60261b86 libsystem_kernel.dylib`__pthread_kill + 10
    frame #1: 0x00007fff60317c50 libsystem_pthread.dylib`pthread_kill + 285
    frame #2: 0x00007fff601cb1c9 libsystem_c.dylib`abort + 127
    frame #3: 0x00007fff5d84d231 libc++abi.dylib`abort_message + 231
    frame #4: 0x00007fff5d84d3b5 libc++abi.dylib`default_terminate_handler() + 241
    frame #5: 0x00007fff5f056c8f libobjc.A.dylib`_objc_terminate() + 105
    frame #6: 0x00007fff5d858dfe libc++abi.dylib`std::__terminate(void (*)()) + 8
    frame #7: 0x00007fff5d858be2 libc++abi.dylib`__cxxabiv1::failed_throw(__cxxabiv1::__cxa_exception*) + 27
    frame #8: 0x00007fff5d84bbb9 libc++abi.dylib`__cxa_throw + 113
    frame #9: 0x000000010127cfe4 libexiv2.27.dylib`Exiv2::XmpProperties::nsInfoUnsafe(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&) + 260
    frame #10: 0x000000010127cdfc libexiv2.27.dylib`Exiv2::XmpProperties::ns(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&) + 300
    frame #11: 0x0000000100fe973c libgexiv2.2.dylib`gexiv2_metadata_register_xmp_namespace + 172

Reverting to 0.26 fixing the issue

[phako]

Which is a bit odd since I've had reports for that with exiv 0.26 on OpenBSD as well: https://gitlab.gnome.org/GNOME/gexiv2/issues/27 which was thought to be related to the symbol hiding script.

[samm-git]

Thanks to @phako issue is now localized and is caused by https://github.com/Exiv2/exiv2/commit/4574a659ccf8ee290f6ecd1be2a81c92105059b8.patch . If i am reverting it - tests works as expected, see https://gitlab.gnome.org/GNOME/gexiv2/issues/27

[phako]

Please ignore my comment regarding OpenBSD, that seems to be different cause with similar symptoms

[phako]

For completeness, minimal example for reproduction:

int main(int argc, char *argv[])
{
        try {
                Exiv2::XmpProperties::ns("gnome");
        } catch (Exiv2::Error &error) {
                std::cerr << "Caught error " << error.what() << "\n";
                Exiv2::XmpProperties::registerNs("http://www.gnome.org/xmp", "gnome");
        }

}

[samm-git]

At least for 0.27 this patch is enough to fix this issue:

https://gitlab.gnome.org/samm-git/gtk-osx/blob/fork-test/patches/exiv2-symbols.patch

[clanmills]

Thanks for reporting this. A curious beast.

I have reproduced the crash with @phako's minimal code (which I put in exifprint.cpp) on a clean copy of the Exiv2 0.27.0 Source bundle:

663 rmills@rmillsmbp:~/Downloads/exiv2-0.27.0-Source/build $ bin/exifprint 
libc++abi.dylib: terminating with uncaught exception of type Exiv2::BasicError<char>: No namespace info available for XMP prefix `gnome'
Abort trap: 6
664 rmills@rmillsmbp:~/Downloads/exiv2-0.27.0-Source/build $

This code also crashes on 'master':

668 rmills@rmillsmbp:~/gnu/github/exiv2/exiv2/build $ cp ~/Downloads/exiv2-0.27.0-Source/samples/exifprint.cpp ../samples
675 rmills@rmillsmbp:~/gnu/github/exiv2/exiv2/build $ make exifprint
[ 27%] Built target exiv2lib_int
[ 47%] Built target exiv2-xmp
[ 98%] Built target exiv2lib
Scanning dependencies of target exifprint
[ 98%] Building CXX object samples/CMakeFiles/exifprint.dir/exifprint.cpp.o
/Users/rmills/gnu/github/exiv2/exiv2/samples/exifprint.cpp:11:14: warning: unused parameter 'argc' [-Wunused-parameter]
int main(int argc, char *argv[])
             ^
/Users/rmills/gnu/github/exiv2/exiv2/samples/exifprint.cpp:11:26: warning: unused parameter 'argv' [-Wunused-parameter]
int main(int argc, char *argv[])
                         ^
2 warnings generated.
[100%] Linking CXX executable ../bin/exifprint
[100%] Built target exifprint
676 rmills@rmillsmbp:~/gnu/github/exiv2/exiv2/build $ bin/exifprint 
libc++abi.dylib: terminating with uncaught exception of type Exiv2::BasicError<char>: No namespace info available for XMP prefix `gnome'
Abort trap: 6
677 rmills@rmillsmbp:~/gnu/github/exiv2/exiv2/build $ 

I have applied the patch: https://gitlab.gnome.org/samm-git/gtk-osx/blob/fork-test/patches/exiv2-symbols.patch The code still crashes and causes a huge linker warning on MacOS-X.

There are considerable "under the hood" changes in v0.27. Our CMake code has been rewritten and symbol visibility is delegated to CMake. I'm sure @piponazo will make comments concerning this.

There was a discussion on pixls last week which I think is related:
https://discuss.pixls.us/t/exiv2-0-27-breaking-api/10662/4

Exiv2 v0.27 will have LTS (Long Term Support) and we intend to publish quarterly "dot" releases with security and minor bug fixes during 2019 and 2020. Exiv2 v0.27.1 is scheduled for 2019-03-31.

There will be a pre-release Exiv2 v0.27.1 RC1 in early March. I hope you will download and test that with your code.

I don't know what 'darwin' is. I assume it's a code work for an up-coming version of gexiv2 or shotwell. If 'darwin' is important to this discussion, please clarify for my benefit.

[piponazo]

Thanks guys for reporting and providing the minimal example for reproduction. I'll work on it tonight 😉

[phako]

@clanmills "darwin" is the name of the OS core used by Apple for iOS and macOS and commonly used to denote thinngs that apply to either iOS or macOS by various build tools.

[clanmills]

Ah. I always spell that as "Darwin". Right. Thanks for the clarification.

I'm mistaken about the proposed fix. The exception is being caught.

701 rmills@rmillsmbp:~/gnu/github/exiv2/exiv2/build $ bin/exifprint 
Caught error No namespace info available for XMP prefix `gnome'
702 rmills@rmillsmbp:~/gnu/github/exiv2/exiv2/build $ 

The exception is correct, as gnome isn't one of the "preregistered" name-spaces which can be listed with the command: $ exiv2 --verbose --version:

707 rmills@rmillsmbp:~/gnu/github/exiv2/exiv2/build $ bin/exifprint 
Caught error No namespace info available for XMP prefix `gnome'
708 rmills@rmillsmbp:~/gnu/github/exiv2/exiv2/build $ exiv2 -vVg xmlns | grep gnome
709 rmills@rmillsmbp:~/gnu/github/exiv2/exiv2/build $ exiv2 -vVg xmlns | grep DICOM
xmlns=DICOM:http://ns.adobe.com/DICOM/
710 rmills@rmillsmbp:~/gnu/github/exiv2/exiv2/build $ 

On MacOS-X, the linker is producing a long stream of warnings when linking libexiv2.dylib:

ld: warning: direct access in function 'Exiv2::Internal::CiffEntry::doAdd(std::__1::auto_ptr<Exiv2::Internal::CiffComponent>)' from file 'CMakeFiles/exiv2lib_int.dir/crwimage_int.cpp.o' to global weak symbol 'typeinfo for Exiv2::BasicError<char>' from file 'CMakeFiles/exiv2lib.dir/basicio.cpp.o' means the weak symbol cannot be overridden at runtime. This was likely caused by different translation units being compiled with different visibility settings.

There's something familiar about this. I believe we've seen a similar warning recently.

Confident that this will be resolved and closed in the next few days. I've added this issue to Milestone 0.27.1

[clanmills]

I decided to take a two stage approach to this:

1. Submit the patch Fix644 on 0.27 #647 Fix 644 on master #649
2. Investigate the linker warning on MacOS-X Linker warning on MacOS-X (after fixing 644) #648

To my surprise the patch broke the msvc build. I will investigate.