cargo/lints/rules/
unused_workspace_dependencies.rs

1use std::path::Path;
2
3use annotate_snippets::AnnotationKind;
4use annotate_snippets::Group;
5use annotate_snippets::Level;
6use annotate_snippets::Origin;
7use annotate_snippets::Patch;
8use annotate_snippets::Snippet;
9use cargo_util_schemas::manifest::InheritableDependency;
10use cargo_util_schemas::manifest::TomlToolLints;
11use indexmap::IndexSet;
12
13use crate::CargoResult;
14use crate::GlobalContext;
15use crate::core::MaybePackage;
16use crate::core::Workspace;
17use crate::lints::Lint;
18use crate::lints::LintLevel;
19use crate::lints::SUSPICIOUS;
20use crate::lints::get_key_value_span;
21use crate::lints::rel_cwd_manifest_path;
22
23pub static LINT: &Lint = &Lint {
24    name: "unused_workspace_dependencies",
25    desc: "unused workspace dependency",
26    primary_group: &SUSPICIOUS,
27    msrv: Some(super::CARGO_LINTS_MSRV),
28    edition_lint_opts: None,
29    feature_gate: None,
30    docs: Some(
31        r#"
32### What it does
33Checks for any entry in `[workspace.dependencies]` that has not been inherited
34
35### Why it is bad
36They can give the false impression that these dependencies are used
37
38### Example
39```toml
40[workspace.dependencies]
41regex = "1"
42
43[dependencies]
44```
45"#,
46    ),
47};
48
49pub fn unused_workspace_dependencies(
50    ws: &Workspace<'_>,
51    maybe_pkg: &MaybePackage,
52    manifest_path: &Path,
53    cargo_lints: &TomlToolLints,
54    error_count: &mut usize,
55    gctx: &GlobalContext,
56) -> CargoResult<()> {
57    let (lint_level, reason) = LINT.level(
58        cargo_lints,
59        ws.lowest_rust_version(),
60        maybe_pkg.edition(),
61        maybe_pkg.unstable_features(),
62    );
63    if lint_level == LintLevel::Allow {
64        return Ok(());
65    }
66
67    let workspace_deps: IndexSet<_> = maybe_pkg
68        .original_toml()
69        .and_then(|t| t.workspace.as_ref())
70        .and_then(|w| w.dependencies.as_ref())
71        .iter()
72        .flat_map(|d| d.keys())
73        .collect();
74
75    let mut inherited_deps = IndexSet::new();
76    for member in ws.members() {
77        let Some(original_toml) = member.manifest().original_toml() else {
78            return Ok(());
79        };
80        inherited_deps.extend(
81            original_toml
82                .build_dependencies()
83                .into_iter()
84                .flatten()
85                .filter(|(_, d)| is_inherited(d))
86                .map(|(name, _)| name),
87        );
88        inherited_deps.extend(
89            original_toml
90                .dependencies
91                .iter()
92                .flatten()
93                .filter(|(_, d)| is_inherited(d))
94                .map(|(name, _)| name),
95        );
96        inherited_deps.extend(
97            original_toml
98                .dev_dependencies()
99                .into_iter()
100                .flatten()
101                .filter(|(_, d)| is_inherited(d))
102                .map(|(name, _)| name),
103        );
104        for target in original_toml.target.iter().flat_map(|t| t.values()) {
105            inherited_deps.extend(
106                target
107                    .build_dependencies()
108                    .into_iter()
109                    .flatten()
110                    .filter(|(_, d)| is_inherited(d))
111                    .map(|(name, _)| name),
112            );
113            inherited_deps.extend(
114                target
115                    .dependencies
116                    .iter()
117                    .flatten()
118                    .filter(|(_, d)| is_inherited(d))
119                    .map(|(name, _)| name),
120            );
121            inherited_deps.extend(
122                target
123                    .dev_dependencies()
124                    .into_iter()
125                    .flatten()
126                    .filter(|(_, d)| is_inherited(d))
127                    .map(|(name, _)| name),
128            );
129        }
130    }
131
132    for (i, unused) in workspace_deps.difference(&inherited_deps).enumerate() {
133        let document = maybe_pkg.document();
134        let contents = maybe_pkg.contents();
135        let level = lint_level.to_diagnostic_level();
136        let manifest_path = rel_cwd_manifest_path(manifest_path, gctx);
137        let emitted_source = LINT.emitted_source(lint_level, reason);
138
139        let mut primary = Group::with_title(level.primary_title(LINT.desc));
140        if let Some(document) = document
141            && let Some(contents) = contents
142        {
143            let mut snippet = Snippet::source(contents).path(&manifest_path);
144            if let Some(span) =
145                get_key_value_span(document, &["workspace", "dependencies", unused.as_str()])
146            {
147                snippet = snippet.annotation(AnnotationKind::Primary.span(span.key));
148            }
149            primary = primary.element(snippet);
150        } else {
151            primary = primary.element(Origin::path(&manifest_path));
152        }
153        if i == 0 {
154            primary = primary.element(Level::NOTE.message(emitted_source));
155        }
156        let mut report = vec![primary];
157        if let Some(document) = document
158            && let Some(contents) = contents
159        {
160            let mut help = Group::with_title(
161                Level::HELP.secondary_title("consider removing the unused dependency"),
162            );
163            let mut snippet = Snippet::source(contents).path(&manifest_path);
164            if let Some(span) =
165                get_key_value_span(document, &["workspace", "dependencies", unused.as_str()])
166            {
167                snippet = snippet.patch(Patch::new(span.key.start..span.value.end, ""));
168            }
169            help = help.element(snippet);
170            report.push(help);
171        }
172
173        if lint_level.is_error() {
174            *error_count += 1;
175        }
176        gctx.shell().print_report(&report, lint_level.force())?;
177    }
178
179    Ok(())
180}
181
182fn is_inherited(dep: &InheritableDependency) -> bool {
183    matches!(dep, InheritableDependency::Inherit(_))
184}
cargo/lints/rules/unused_workspace_dependencies.rs

cargo/lints/rules/
unused_workspace_dependencies.rs
