json output: unused_deps may be non-empty even if all dependencies are used

[nagisa]

{"success":true,"unused_deps":{"some crate":{"manifest_path":"/some/location","normal":[],"development":[],"build":[]}},"note":null}

is what I see when I build a workspace with many crates. The unused_deps map gets populated with further crates if and when they contain unused crates.

I think it might be because the some_crate is the only crate that has cargo-udeps.ignore specified in it.

[est31]

Might be one of the known false positives? The cli version shows a warning that this is possible.

[nagisa]

Note that there are no reported unused dependencies, all of the normal, development and build arrays for that crate are empty. Furthermore json contains both success: true and udeps' exit code is 0.

[nagisa]

All in all it is fairly low prio to fix, just something I noticed and found weird.

[qryxip]

I've found the cause. It checks if the dependency is ignored after inserting ([], [], []).

cargo-udeps/src/lib.rs

Lines 473 to 485 in 13ea330

	if !used_dependencies.contains(&(id, dependency)) {
	let outcome = outcome
	.unused_deps
	.entry(id)
	.or_insert(OutcomeUnusedDeps::new(packages[&id].manifest_path())?)
	.unused_deps_mut(*kind);
	if ignore.map_or(false, |ignore| ignore.contains(*kind, dependency)) {
	config.shell().info(format_args!("Ignoring `{}` ({:?})", dependency, kind))?;
	} else {
	outcome.insert(dependency);
	}
	}

I don't remember the reason why we pass ([], [], []).

(edit) I mean, why we considered ([], [], []) was possible before #59.

cargo-udeps/src/lib.rs

Lines 489 to 494 in 13ea330

	outcome.success = outcome
	.unused_deps
	.values()
	.all(|OutcomeUnusedDeps { normal, development, build, .. }| {
	normal.is_empty() && development.is_empty() && build.is_empty()
	});

[qryxip]

I've just noticed the --output json option is not documented at all. Maybe we should write some descriptions.

[qryxip]

Either way this issue is actually weird and should be fixed.