Fails to build because of hidden symbols

[Vogtinator]

The visibility changes in as-tag.c break building:

[   88s] FAILED: src/libappstream.so.0.12.2 
[   88s] cc  -o src/libappstream.so.0.12.2 'src/src@@@appstream@sha/meson-generated_.._as-resources.c.o' 'src/src@@@appstream@sha/as-utils.c.o' 'src/src@@@appstream@sha/as-tag.c.o' 'src/src@@@appstream@sha/as-context.c.o' 'src/src@@@appstream@sha/as-xml.c.o' 'src/src@@@appstream@sha/as-yaml.c.o' 'src/src@@@appstream@sha/as-variant-cache.c.o' 'src/src@@@appstream@sha/as-desktop-entry.c.o' 'src/src@@@appstream@sha/as-distro-extras.c.o' 'src/src@@@appstream@sha/as-stemmer.c.o' 'src/src@@@appstream@sha/as-spdx.c.o' 'src/src@@@appstream@sha/as-metadata.c.o' 'src/src@@@appstream@sha/as-component.c.o' 'src/src@@@appstream@sha/as-enums.c.o' 'src/src@@@appstream@sha/as-provided.c.o' 'src/src@@@appstream@sha/as-bundle.c.o' 'src/src@@@appstream@sha/as-pool.c.o' 'src/src@@@appstream@sha/as-category.c.o' 'src/src@@@appstream@sha/as-distro-details.c.o' 'src/src@@@appstream@sha/as-screenshot.c.o' 'src/src@@@appstream@sha/as-image.c.o' 'src/src@@@appstream@sha/as-release.c.o' 'src/src@@@appstream@sha/as-checksum.c.o' 'src/src@@@appstream@sha/as-validator.c.o' 'src/src@@@appstream@sha/as-validator-issue.c.o' 'src/src@@@appstream@sha/as-icon.c.o' 'src/src@@@appstream@sha/as-translation.c.o' 'src/src@@@appstream@sha/as-suggested.c.o' 'src/src@@@appstream@sha/as-content-rating.c.o' 'src/src@@@appstream@sha/as-launchable.c.o' 'src/src@@@appstream@sha/as-relation.c.o' 'src/src@@@appstream@sha/as-agreement.c.o' 'src/src@@@appstream@sha/as-agreement-section.c.o' -Wl,--no-undefined -Wl,--as-needed -shared -fPIC -Wl,--start-group -Wl,-soname,libappstream.so.4 -fmessage-length=0 -grecord-gcc-switches -O2 -Wall -D_FORTIFY_SOURCE=2 -fstack-protector-strong -funwind-tables -fasynchronous-unwind-tables -fstack-clash-protection -g -lglib-2.0 -Wl,--end-group -lxml2 -lyaml -lgobject-2.0 -lglib-2.0 -lgio-2.0 -lgobject-2.0 -lglib-2.0  
[   88s] src/src@@@appstream@sha/as-validator.c.o: In function `as_validator_validate_component_node':
[   88s] /home/abuild/rpmbuild/BUILD/AppStream-0.12.2/build/../src/as-validator.c:1451: undefined reference to `strlen'
[   88s] src/src@@@appstream@sha/as-validator.c.o: In function `as_validator_check_description_tag':
[   88s] /home/abuild/rpmbuild/BUILD/AppStream-0.12.2/build/../src/as-validator.c:471: undefined reference to `strlen'
[   88s] src/src@@@appstream@sha/as-utils.c.o: In function `as_gstring_replace':
[   88s] /home/abuild/rpmbuild/BUILD/AppStream-0.12.2/build/../src/as-utils.c:481: undefined reference to `strlen'
[   88s] /home/abuild/rpmbuild/BUILD/AppStream-0.12.2/build/../src/as-utils.c:482: undefined reference to `strlen'
[   88s] src/src@@@appstream@sha/as-utils.c.o: In function `as_utils_search_token_valid':
[   88s] /home/abuild/rpmbuild/BUILD/AppStream-0.12.2/build/../src/as-utils.c:842: undefined reference to `strlen'
[   88s] src/src@@@appstream@sha/as-utils.c.o:/home/abuild/rpmbuild/BUILD/AppStream-0.12.2/build/../src/as-utils.c:1021: more undefined references to `strlen' follow
[   88s] src/src@@@appstream@sha/as-utils.c.o: In function `as_utils_compare_versions':
[   88s] /home/abuild/rpmbuild/BUILD/AppStream-0.12.2/build/../src/as-utils.c:1103: undefined reference to `strcmp'
[   88s] /home/abuild/rpmbuild/BUILD/AppStream-0.12.2/build/../src/as-utils.c:1093: undefined reference to `strlen'
[   88s] /home/abuild/rpmbuild/BUILD/AppStream-0.12.2/build/../src/as-utils.c:1094: undefined reference to `strlen'
[   88s] src/src@@@appstream@sha/as-tag.c.o: In function `_as_xml_tag_from_gperf':
[   88s] /home/abuild/rpmbuild/BUILD/AppStream-0.12.2/build/../src/as-tag-xml.gperf:38: undefined reference to `strcmp'
[   88s] src/src@@@appstream@sha/as-tag.c.o: In function `_as_yaml_tag_from_gperf':
[   88s] /home/abuild/rpmbuild/BUILD/AppStream-0.12.2/build/../src/as-tag-yaml.gperf:45: undefined reference to `strcmp'
[   88s] src/src@@@appstream@sha/as-tag.c.o: In function `as_xml_tag_from_string':
[   88s] /home/abuild/rpmbuild/BUILD/AppStream-0.12.2/build/../src/as-tag.c:70: undefined reference to `strlen'
[   88s] src/src@@@appstream@sha/as-tag.c.o: In function `as_yaml_tag_from_string':
[   88s] /home/abuild/rpmbuild/BUILD/AppStream-0.12.2/build/../src/as-tag.c:98: undefined reference to `strlen'
[   88s] src/src@@@appstream@sha/as-xml.c.o: In function `as_xml_add_description_node_helper':
[   88s] /home/abuild/rpmbuild/BUILD/AppStream-0.12.2/build/../src/as-xml.c:278: undefined reference to `strlen'
[   88s] src/src@@@appstream@sha/as-xml.c.o: In function `as_xml_parse_document':
[   88s] /home/abuild/rpmbuild/BUILD/AppStream-0.12.2/build/../src/as-xml.c:552: undefined reference to `strlen'
[   88s] src/src@@@appstream@sha/as-yaml.c.o: In function `as_yaml_emit_scalar':
[   88s] /home/abuild/rpmbuild/BUILD/AppStream-0.12.2/build/../src/as-yaml.c:242: undefined reference to `strlen'
[   88s] src/src@@@appstream@sha/as-yaml.c.o:/home/abuild/rpmbuild/BUILD/AppStream-0.12.2/build/../src/as-yaml.c:265: more undefined references to `strlen' follow
[   88s] collect2: error: ld returned 1 exit status

[ximion]

Hmm, is there anything special about your system? The software builds fine for me, and the CI is happy as well, additionally there were no changes to as-tag for quite a while and the Debian package builds as well.
An undefined reference to strlen, strcmp etc. feels like the library isn't linked to the C standard library, which is quite odd.

[Vogtinator]

It builds fine on openSUSE Tumbleweed, but fails reproducibly on Leap 15.0.

Adding #include <string.h> before the visibility changes in as-tag.c fixes this.

[ximion]

Interesting. Potentially this fails with a newer GCC?
Including string.h makes sense, would you mind creating a PR for that? Otherwise I will just make that change in a few hours when I'm home.

[Vogtinator]

Interesting. Potentially this fails with a newer GCC?

Older, actually. GCC 7.3.1 fails, but 8.2.1 works. It might also be binutils causing this.

Including string.h makes sense, would you mind creating a PR for that? Otherwise I will just make that change in a few hours when I'm home.

I could create a PR, but I'm not sure that it's the right solution. It's necessary because the includes with hidden default visibility include string.h, so once any include file referenced there changes, this needs to be adjusted.

[ximion]

I think for now this is a good solution. I really don't want to have the gperf-related symbols exported, and I don't see a better way to resolve this.