Duplicated requirement for version range

I created a few recipes that used version ranges for dependencies using semantic versioning. In the following example libcurl depends to libssh2/[~=1.8]@theirix/stable and libssh2 depends to zlib/[~=1.2]@lasote/stable. Also I have fixed zlib at 1.2.11 in the project conanfile. The package OpenSSL/1.0.2k@lasote/stable depends strictly on zlib/1.2.11@lasote/stable. See a gist for a complete dependency list.

I am expecting that the dependency graph resolves strictly to zlib/1.2.11 but it is failing with: Duplicated requirement zlib/1.2.11@lasote/stable != zlib/[~=1.2]@lasote/stable

Should it really fail or is it a bug?

Test conanfile. All other recipes are from conan.io.

Full output:

libcurl/7.52.1@theirix/stable requirement zlib/[~=1.2]@lasote/stable overriden by your conanfile to zlib/1.2.11@lasote/stable
libcurl/7.52.1@theirix/stable requirement libssh2/[~=1.8]@theirix/testing overriden by your conanfile to libssh2/1.8.0@theirix/stable
Version range '~=1.2' required by 'libcurl/7.52.1@theirix/stable' valid for downstream requirement 'zlib/1.2.11@lasote/stable'
Version range '~=1.8' required by 'libcurl/7.52.1@theirix/stable' valid for downstream requirement 'libssh2/1.8.0@theirix/stable'
libssh2/1.8.0@theirix/stable requirement zlib/[~=1.2]@lasote/stable overriden by libcurl/7.52.1@theirix/stable to zlib/1.2.11@lasote/stable
libssh2/1.8.0@theirix/stable requirement OpenSSL/[>1.0.2a,<1.0.3]@lasote/stable overriden by libcurl/7.52.1@theirix/stable to OpenSSL/1.0.2k@lasote/stable
Version range '~=1.2' required by 'libssh2/1.8.0@theirix/stable' valid for downstream requirement 'zlib/1.2.11@lasote/stable'
Version range '>1.0.2a,<1.0.3' required by 'libssh2/1.8.0@theirix/stable' valid for downstream requirement 'OpenSSL/1.0.2k@lasote/stable'
ERROR: libssh2/1.8.0@theirix/stable: Duplicated requirement zlib/1.2.11@lasote/stable != zlib/[~=1.2]@lasote/stable

[theirix]

Thanks for the hint. I’ll try to fix my packages accordingly.

[memsharded]

Great! thanks for telling