SemverQuery(
id: "feature_no_longer_enables_feature",
human_readable_name: "package feature no longer enables another feature",
description: "A feature no longer enables another feature in this package's Cargo.toml.",
required_update: Major,
lint_level: Deny,
reference_link: Some("https://doc.rust-lang.org/cargo/reference/semver.html#cargo-feature-remove-another"),
query: r#"
{
CrateDiff {
baseline {
feature {
# Until cargo ships with support for private and/or unstable feature names,
# we'll rely on feature names to detect whether to flag feature changes.
#
# This lint will ignore features that match any of the following:
# - start with an underscore (`_`) character
# - are named `unstable`, `nightly`, or `bench`
# - have a prefix of `unstable`, `nightly`, or `bench` followed by
# a dash (`-`) or underscore (`_`) character.
#
# Cargo tracking issues:
# - unstable/nightly features: https://github.com/rust-lang/cargo/issues/10881
# - private/hidden features: https://github.com/rust-lang/cargo/issues/10882
# Exclude the `default` feature so default-feature changes are handled by
# the `feature_not_enabled_by_default` lint.
feature_name: name @tag
@filter(op: "not_regex", value: ["$unstable_feature_pattern"])
@filter(op: "not_has_prefix", value: ["$underscore"])
@filter(op: "!=", value: ["$default_feature_name"])
@output
# An explicit ordering key is needed since we don't have span information,
# which what we usually use to order results in tests.
name @output(name: "ordering_key")
directly_enables {
implied_feature_name: name @tag
@filter(op: "not_regex", value: ["$unstable_feature_pattern"])
@filter(op: "not_has_prefix", value: ["$underscore"])
@output
# An explicit ordering key is needed since we don't have span information,
# which what we usually use to order results in tests.
name @output(name: "ordering_key1")
}
}
}
current {
# Ensure the feature still exists. If it's missing entirely, we want to report
# it in the `feature_missing` lint, not here.
feature {
name @filter(op: "=", value: ["%feature_name"])
# Follow the full transitive feature graph in case the implication was rerouted.
transitively_enables @fold
@transform(op: "count")
@filter(op: "=", value: ["$zero"]) {
name @filter(op: "=", value: ["%implied_feature_name"])
}
}
# Ensure the implied feature still exists. If it's missing entirely, we want
# to report it in the `feature_missing` lint, not here.
feature @fold @transform(op: "count") @filter(op: ">", value: ["$zero"]) {
name @filter(op: "=", value: ["%implied_feature_name"])
}
}
}
}"#,
arguments: {
"zero": 0,
"unstable_feature_pattern": "^(?:unstable|nightly|bench)(?:[-_].*)?$",
"underscore": "_",
"default_feature_name": "default",
},
error_message: "A feature no longer enables another feature in this package's Cargo.toml. This will break downstream crates which rely on the implied feature being enabled.",
per_result_error_template: Some("feature {{feature_name}} no longer enables {{implied_feature_name}}"),
// TODO: It's currently not possible to write witnesses for manifest lints,
// since we'd need to generate a *Cargo.toml* witness instead of a Rust code witness.
// Issue: https://github.com/obi1kenobi/cargo-semver-checks/issues/1008
witness: None,
)