Add targets to MSRV cargo check

[rustworthy]

as per this thread

[jonhoo]

My only worry is that --lib will fail if there is no library (i.e., a binary-only crate) and --bins will fail if there are no binaries (and also --examples if there are no examples)? Could you please check that that's not the case?

[rustworthy]

My only worry is that --lib will fail if there is no library (i.e., a binary-only crate) and --bins will fail if there are no binaries (and also --examples if there are no examples)? Could you please check that that's not the case?

I just realized I forgot to add the --all-features flag - since this is what was actually discovered in the faktory-rs crate and led to this PR here upstream.

As for your worries - you are right, but, interestingly, --bins and --examples will not fail if targets are not there, rather emit a warning, e.g. for a crate which is only a library, running cargo check --all-features --bins --examples (w/o --lib) will exit successfully but emit:

warning: target filters `bins`, `examples` specified, but no targets matched; this is a no-op

While in case of running cargo check --all-features --bins --examples --lib (note the --lib flag), even that warning will be suppressed (at least with the regular verbosity).

BUT! If this is a binary crate, and we run it with the command above, we get an error error: no library targets found in package

Possible ways out:

• we can read manifest as suggested here and run cargo check --all-features --bins --examples --lib if a lib target is there. Me running cargo read-manifest | jq .targets outputs:

 [
  {
    "kind": [
      "lib"
    ],
    "crate_types": [
      "lib"
    ],
    "name": "checking",
    "src_path": "/tmp/checking/src/lib.rs",
    "edition": "2024",
    "doc": true,
    "doctest": true,
    "test": true
  },
  {
    "kind": [
      "bin"
    ],
    "crate_types": [
      "bin"
    ],
    "name": "checking",
    "src_path": "/tmp/checking/src/main.rs",
    "edition": "2024",
    "doc": true,
    "doctest": false,
    "test": true
  }
]

• we can simply leave cargo check --all-features in this CI job with a comment that folks should enable other targets, such as --lib, --bins and --examples, as needed.

[jonhoo]

I like the idea of auto-detecting here I think — it's always unfortunate if users need to carry permanent diffs!