drft/rules/
directed_cycle.rs

1use crate::diagnostic::Diagnostic;
2use crate::rules::{Rule, RuleContext};
3
4pub struct DirectedCycleRule;
5
6impl Rule for DirectedCycleRule {
7    fn name(&self) -> &str {
8        "directed-cycle"
9    }
10
11    fn evaluate(&self, ctx: &RuleContext) -> Vec<Diagnostic> {
12        let result = &ctx.graph.scc;
13
14        result
15            .sccs
16            .iter()
17            .map(|scc| {
18                let mut path = scc.members.clone();
19                if let Some(first) = path.first().cloned() {
20                    path.push(first);
21                }
22
23                let fix = format!(
24                    "circular dependency \u{2014} review whether one of these links can be removed or the content restructured: {}",
25                    scc.members.join(" \u{2192} ")
26                );
27
28                Diagnostic {
29                    rule: "directed-cycle".into(),
30                    message: "cycle detected".into(),
31                    path: Some(path),
32                    fix: Some(fix),
33                    ..Default::default()
34                }
35            })
36            .collect()
37    }
38}
39
40#[cfg(test)]
41mod tests {
42    use super::*;
43    use crate::graph::Graph;
44    use crate::graph::test_helpers::{make_edge, make_enriched, make_node};
45    use crate::rules::RuleContext;
46
47    #[test]
48    fn detects_simple_cycle() {
49        let mut graph = Graph::new();
50        graph.add_node(make_node("a.md"));
51        graph.add_node(make_node("b.md"));
52        graph.add_node(make_node("c.md"));
53        graph.add_edge(make_edge("a.md", "b.md"));
54        graph.add_edge(make_edge("b.md", "c.md"));
55        graph.add_edge(make_edge("c.md", "a.md"));
56
57        let enriched = make_enriched(graph);
58        let ctx = RuleContext {
59            graph: &enriched,
60            options: None,
61        };
62        let diagnostics = DirectedCycleRule.evaluate(&ctx);
63        assert_eq!(diagnostics.len(), 1);
64        assert_eq!(diagnostics[0].rule, "directed-cycle");
65
66        let path = diagnostics[0].path.as_ref().unwrap();
67        assert_eq!(path.first(), path.last());
68        assert!(path.contains(&"a.md".to_string()));
69        assert!(path.contains(&"b.md".to_string()));
70        assert!(path.contains(&"c.md".to_string()));
71    }
72
73    #[test]
74    fn no_cycle_in_dag() {
75        let mut graph = Graph::new();
76        graph.add_node(make_node("a.md"));
77        graph.add_node(make_node("b.md"));
78        graph.add_node(make_node("c.md"));
79        graph.add_edge(make_edge("a.md", "b.md"));
80        graph.add_edge(make_edge("b.md", "c.md"));
81
82        let enriched = make_enriched(graph);
83        let ctx = RuleContext {
84            graph: &enriched,
85            options: None,
86        };
87        let diagnostics = DirectedCycleRule.evaluate(&ctx);
88        assert!(diagnostics.is_empty());
89    }
90
91    #[test]
92    fn ignores_broken_link_edges() {
93        let mut graph = Graph::new();
94        graph.add_node(make_node("a.md"));
95        graph.add_edge(make_edge("a.md", "missing.md"));
96
97        let enriched = make_enriched(graph);
98        let ctx = RuleContext {
99            graph: &enriched,
100            options: None,
101        };
102        let diagnostics = DirectedCycleRule.evaluate(&ctx);
103        assert!(diagnostics.is_empty());
104    }
105}
drft/rules/directed_cycle.rs

drft/rules/
directed_cycle.rs
