feat(notgraph): implement crate_graph collector

crates/notgraph/src/crate_graph.rs

@@ -0,0 +1,49 @@
+use crate::types::{CrateGraph, CrateName};
+use anyhow::Result;
+
+pub fn build(manifest_path: &std::path::Path) -> Result<CrateGraph> {
+    let meta = cargo_metadata::MetadataCommand::new()
+        .manifest_path(manifest_path)
+        .no_deps()
+        .exec()?;
+
+    let workspace_members: std::collections::HashSet<String> = meta
+        .workspace_members
+        .iter()
+        .filter_map(|id| meta.packages.iter().find(|p| &p.id == id))
+        .map(|p| p.name.clone())
+        .collect();
+
+    let nodes: Vec<CrateName> = workspace_members.iter().cloned().collect();
+
+    let mut edges: Vec<(CrateName, CrateName)> = Vec::new();
+    for pkg in meta.packages.iter().filter(|p| workspace_members.contains(&p.name)) {
+        for dep in &pkg.dependencies {
+            if workspace_members.contains(&dep.name) {
+                edges.push((pkg.name.clone(), dep.name.clone()));
+            }
+        }
+    }
+
+    Ok(CrateGraph { nodes, edges })
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn builds_crate_graph_for_workspace() {
+        let manifest = std::path::Path::new(env!("CARGO_MANIFEST_DIR"))
+            .parent().unwrap()
+            .parent().unwrap()
+            .join("Cargo.toml");
+
+        let graph = build(&manifest).unwrap();
+
+        assert!(graph.nodes.contains(&"notgraph".to_string()));
+        assert!(graph.nodes.contains(&"notcore".to_string()));
+        assert!(graph.edges.contains(&("notstrap".to_string(), "notfiles".to_string())));
+        assert!(!graph.edges.iter().any(|(from, _)| from == "notcore"));
+    }
+}

crates/notgraph/src/lib.rs

@@ -1 +1,2 @@
+pub mod crate_graph;
 pub mod types;