WIP - get plumbing for nominate_cycle_breakers in rust

Author: seddonym

rust/src/graph/cycle_breakers.rs

@@ -0,0 +1,12 @@
+use crate::errors::GrimpResult;
+use crate::graph::{Graph, ModuleToken};
+use rustc_hash::FxHashSet;
+
+impl Graph {
+    pub fn nominate_cycle_breakers(
+        &self,
+        _package: ModuleToken,
+    ) -> GrimpResult<FxHashSet<(ModuleToken, ModuleToken)>> {
+        Ok(FxHashSet::default())
+    }
+}

rust/src/graph/mod.rs

@@ -25,6 +25,7 @@ pub mod hierarchy_queries;
 pub mod higher_order_queries;
 pub mod import_chain_queries;
 
+pub mod cycle_breakers;
 pub(crate) mod pathfinding;
 
 static MODULE_NAMES: LazyLock<RwLock<StringInterner<StringBackend>>> =
@@ -619,6 +620,33 @@ impl GraphWrapper {
         self.convert_package_dependencies_to_python(py, illegal_dependencies)
     }
 
+    pub fn nominate_cycle_breakers<'py>(
+        &self,
+        py: Python<'py>,
+        package: &str,
+    ) -> PyResult<Bound<'py, PySet>> {
+        let package = self.get_visible_module_by_name(package)?.token();
+        let cycle_breakers = self._graph.nominate_cycle_breakers(package)?;
+        PySet::new(
+            py,
+            cycle_breakers
+                .into_iter()
+                .map(|(importer, imported)| {
+                    let importer = self._graph.get_module(importer).unwrap();
+                    let imported = self._graph.get_module(imported).unwrap();
+                    Import::new(importer.name(), imported.name())
+                })
+                .map(|import| {
+                    [
+                        ("importer", import.importer.into_py_any(py).unwrap()),
+                        ("imported", import.imported.into_py_any(py).unwrap()),
+                    ]
+                    .into_py_dict(py)
+                    .unwrap()
+                }),
+        )
+    }
+
     #[pyo3(name = "clone")]
     pub fn clone_py(&self) -> GraphWrapper {
         self.clone()

src/grimp/application/graph.py

@@ -450,6 +450,10 @@ def nominate_cycle_breakers(self, package: str) -> set[ImportTuple]:
         """
         Identify a set of imports that, if removed, would make the package locally acyclic.
         """
+        # Check plumbing - not implemented yet.
+        rust_result = self._rustgraph.nominate_cycle_breakers(package)
+        assert rust_result == set()
+
         children = self.find_children(package)
         if len(children) < 2:
             return set()