Suggest workspace shorthands for boolean dependencie

[borngraced]

Error complains about a boolean but only mentions version strings or tables with version = "x.y.z" when you accidentally write:

[dependencies]
crc32fast = true

Cargo reports:

invalid type: boolean `true`, expected a version string like "0.9.8"
or a detailed dependency like { version = "0.9.8" }
in `dependencies.crc32fast`

It would be more helpful if the error message also suggested the workspace shorthand. Both of these are valid ways to pull from your workspace

crc32fast = { workspace = true }
crc32fast.workspace = true

Proposed behavior:

When a boolean is found, append a note pointing out the two valid workspace forms

invalid type: boolean `true`, expected a version string like "0.9.8"
or a detailed dependency like { version = "0.9.8" }
in `dependencies.crc32fast`.

if you meant to use a workspace member, you can write
  crc32fast = { workspace = true }
or
  crc32fast.workspace = true

[epage]

We already manually implement the deserializer

cargo/crates/cargo-util-schemas/src/manifest/mod.rs

Lines 779 to 787 in a154422

	UntaggedEnumVisitor::new()
	.expecting(
	"a version string like \"0.9.8\" or a \
	detailed dependency like { version = \"0.9.8\" }",
	)
	.string(|value| Ok(TomlDependency::Simple(value.to_owned())))
	.map(|value| value.deserialize().map(TomlDependency::Detailed))
	.deserialize(deserializer)
	}

We could add a bool case that just returns this error message.

I wonder if we should also add one for integers and floats to suggest the value with quotes.

[epage]

I've gone ahead and marked this as accepted.

For anyone who pick this up, as a reminder, we would prefer that PRs be split up

• A commit for adding tests in their own commit before other changes, showing the existing error message(s)
• A commit for the bool change that updates the test to show the new error output
• If you do ints/floats, please fix that in a separate commit

For where to put the tests,

cargo/tests/testsuite/bad_config.rs

Line 2618 in a154422

fn bad_dependency() {

is already a test for an integer, so that could be used for that case and a bool test could be added near it.

[borngraced]

@epage i want to give this a shot

[epage]

Thanks!