cargo-metadata always resolves features at the workspace level

[sfackler]

Problem
cargo-metadata appears to always resolve features at the "workspace" level, rather than for root crate. This means that cargo metadata will report features as enabled that aren't actually when cargo build is run in the same directory.

Steps

1. Clone https://github.com/sfackler/rust-postgres
2. Run cargo metadata --format-version 1 --manifest-path postgres-derive/Cargo.toml | jq '.resolve.nodes|.[]|select(.id|test("postgres-types"))'.
3. Note that the entry for postgres-types has the derive and postgres-derive features enabled even though they are off by default for that crate. The postgres-derive-test crate in the same workspace enables that feature, which I assume is where that's coming from:

{
  "id": "postgres-types 0.1.0 (path+file:///home/sfackler/code/rust-postgres/postgres-types)",
  "dependencies": [
    "bytes 0.5.3 (registry+https://github.com/rust-lang/crates.io-index)",
    "fallible-iterator 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
    "postgres-derive 0.4.0 (path+file:///home/sfackler/code/rust-postgres/postgres-derive)",
    "postgres-protocol 0.5.0 (path+file:///home/sfackler/code/rust-postgres/postgres-protocol)"
  ],
  "deps": [
    {
      "name": "bytes",
      "pkg": "bytes 0.5.3 (registry+https://github.com/rust-lang/crates.io-index)",
      "dep_kinds": [
        {
          "kind": null,
          "target": null
        },
        {
          "kind": null,
          "target": null
        }
      ]
    },
    {
      "name": "fallible_iterator",
      "pkg": "fallible-iterator 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
      "dep_kinds": [
        {
          "kind": null,
          "target": null
        },
        {
          "kind": null,
          "target": null
        }
      ]
    },
    {
      "name": "postgres_derive",
      "pkg": "postgres-derive 0.4.0 (path+file:///home/sfackler/code/rust-postgres/postgres-derive)",
      "dep_kinds": [
        {
          "kind": null,
          "target": null
        }
      ]
    },
    {
      "name": "postgres_protocol",
      "pkg": "postgres-protocol 0.5.0 (path+file:///home/sfackler/code/rust-postgres/postgres-protocol)",
      "dep_kinds": [
        {
          "kind": null,
          "target": null
        },
        {
          "kind": null,
          "target": null
        }
      ]
    }
  ],
  "features": [
    "derive",
    "postgres-derive"
  ]
}

Possible Solution(s)
cargo metadata should respect the root crate when resolving the crate graph.

Notes

Output of cargo version: cargo 1.41.0-nightly (19a0de2 2019-12-12)

[emakryo]

Are there any workarounds for this?
cargo tree seems to work as expected.

[sffc]

A possible workaround for this issue is to create a dedicated package where you run cargo metadata, and then add that package to the workspace.exclude list in the top-level Cargo.toml file.