project('dep-test', 'c') dep = dependency('', required:false) if dep.found() error('not-found dependency was found') endif assert(dep.type_name() == 'not-found', 'dependency should be of type "not-found" not ' + dep.type_name()) library('testlib', 'testlib.c', dependencies: [dep]) subdir('sub', if_found: dep) subdep = dependency('', fallback: ['trivial', 'trivial_dep']) missing = dependency('', fallback: ['missing', 'missing_dep'], required: false)