Specifying link order of a conan package

[kevswims]

I have a conan package that includes a set of prebuilt binaries. ie. liba.a and libb.a. When calling
target_link_libraries(nameOfSharedLibrary CONAN_PKG::PackageName)
the libraries are linked to in the wrong order (libb.a liba.a). To work around this I am linking to these I am calling
target_link_libraries(nameOfSharedLibrary ${CONAN_LIB_DIRS_PACKAGENAME}/liba.a ${CONAN_LIB_DIRS_PACKAGENAME}/libb.b).

Is there a way to specify what this link order should be for a package? Either when creating the package or from the consuming project?

[memsharded]

I think the libraries should be in the order they are declared in the package_info() method, like:

def package_info(self):
    self.cpp_info.libs = ["a", "b"]

Can you please check your package_info()? If not maybe it is a bug and should be fixed.

[kevswims]

Looks like I was using self.cpp_info.libs = self.collect_libs() I will try explicitly setting them. Does self.collect_libs() sort by alphabetic order?

[memsharded]

Nop, under the hood collect_libs() is using a os.listdir call, which does not guarantee the result order. And enforcing an alphabetic order on them in conan code is also quite arbitrary. I suggest going for the explicit definition, it should be more robust than the collects_libs one.

[danimtb]

There is an issue about this to add a warning in the docs conan-io/docs#443 due to the same issue here #2201

[r-darwish]

I'm replying here as a followup for this issue. This issue is a bug in the package itself. However, due to the arbitrary order of os.listdir this bug was hard to reproduce and track down. It occurred on some machines, and on some didn't.

I agree that sorting the libraries alphabetically won't magically solve the dependency graph, and that it is up to the package maintainer to maintain the correct order. However, making tools.collect_libs's order deterministic will help spotting such issues.

[danimtb]

Hi @r-darwish

There is no bug in the behavior of tools.collect_libs() as there is a warning regarding the order in the documentation. However, I see your point and maybe it should follow the same alphabetically order in all OS to be mor consistent.

Would you like to contribute with that enhancement? 😄

[danimtb]

I thinks this could be closed due to lack of activity. Please open a new issue with info updated for tools.collect_libs() enhancements if needed.