> the build graph -- the very thing that BUILD files define -- is the best place to encode [dependencies] in a programmatic manner.

so the thing is that a BUILD file doesn't define the build graph, it approximates it -- the build graph is always defined by language-specific tooling and specifications

it's fine that the BUILD file is an approximation! that's as good as you can do, if you want to try to model dep relationships between heterogeneous languages

so when we're talking about the dep graph, "using language-specific tooling" isn't a detail you can brush aside, it's a core requirement for correctness, really