base does not necessarily tell you when circular dependency occurs

[fvaccari]

When updating ports on 10.6 we seem to be lost in a cyclic dependency, but base doesn't seem too helpful communicating this information.

$ sudo port -v upgrade outdated
Warning: No port clang-9.0 found in the index.
Warning: No port legacy-support found in the index.
Warning: No port curl found in the index.
Warning: No port expat found in the index.
Warning: No port bzip2 found in the index.
Warning: No port libarchive found in the index.
Warning: No port libuv found in the index.
Warning: No port legacy-support found in the index.
--->  Computing dependencies for cmakeError: Problem while installing cmake
Error: Follow https://guide.macports.org/#project.tickets to report a bug.

See the logs