For some reason emerging net-libs/libsoup[vala] doesn't trigger dependency on dev-lang/vala. In case vala hasn't been installed for another reason already, the emerge is going to fail.
Seems pull the missing dev-lang/vala just fine for me: $ USE="vala introspection" emerge -1av libsoup These are the packages that would be merged, in order: [ebuild N ] dev-libs/vala-common-0.48.9::gentoo 3,392 KiB [ebuild N ] dev-libs/gobject-introspection-1.64.1-r1::gentoo USE="-doctool -gtk-doc -test" PYTHON_SINGLE_TARGET="python3_8 -python3_6 -python3_7" 0 KiB [ebuild N ] dev-lang/vala-0.48.9:0.48::gentoo USE="-test -valadoc" 0 KiB [ebuild R ] net-libs/libsoup-2.70.0:2.4::gentoo USE="introspection* ssl vala* -brotli -gssapi -gtk-doc -samba -test" ABI_X86="(64) -32 (-x32)" 0 KiB I've ran that rebuild too and there was no issue.
(In reply to Petr Cerny [:hrosik] from comment #0) > For some reason emerging net-libs/libsoup[vala] doesn't trigger dependency > on dev-lang/vala. In case vala hasn't been installed for another reason > already, the emerge is going to fail. Please attach the net-libs/libsoup build log showing how that fails. Please post your `emerge --info' output in a comment.