head-revs: merge the two inner_headrevs… variants

Now that there is only one method, it does not make sense to have two different
"inner" method. This is especially true as we are about to add another parameter
to the method. So we clean up before that.

rust/hg-cpython/src/revlog.rs

@@ -310,12 +310,7 py_class!(pub class Index |py| {
              1 => Ok(args.get_item(py, 0)),
              _ => Err(PyErr::new::<cpython::exc::TypeError, _>(py, "too many arguments")),
         }?;
-        let rust_res = if filtered_revs.is_none(py) {
-            self.inner_headrevs(py)
-        } else {
-            self.inner_headrevsfiltered(py, &filtered_revs)
-        }?;
-        Ok(rust_res)
+        self.inner_headrevs(py, &filtered_revs)
     }
 
     /// get head nodeids
@@ -822,35 +817,23 impl Index {
         Ok(PyList::new(py, &res).into_object())
     }
 
-    fn inner_headrevs(&self, py: Python) -> PyResult<PyObject> {
-        let index = &*self.index(py).borrow();
-        if let Some(new_heads) =
-            index.head_revs_shortcut().map_err(|e| graph_error(py, e))?
-        {
-            self.cache_new_heads_py_list(&new_heads, py);
-        }
-
-        Ok(self
-            .head_revs_py_list(py)
-            .borrow()
-            .as_ref()
-            .expect("head revs should be cached")
-            .clone_ref(py)
-            .into_object())
-    }
-
-    fn inner_headrevsfiltered(
+    fn inner_headrevs(
         &self,
         py: Python,
         filtered_revs: &PyObject,
     ) -> PyResult<PyObject> {
         let index = &*self.index(py).borrow();
-        let filtered_revs = rev_pyiter_collect(py, filtered_revs, index)?;
 
-        if let Some(new_heads) = index
-            .head_revs_filtered(&filtered_revs, true)
-            .map_err(|e| graph_error(py, e))?
-        {
+        let from_core = match filtered_revs.is_none(py) {
+            true => index.head_revs_shortcut(),
+            false => {
+                let filtered_revs =
+                    rev_pyiter_collect(py, filtered_revs, index)?;
+                index.head_revs_filtered(&filtered_revs, true)
+            }
+        };
+
+        if let Some(new_heads) = from_core.map_err(|e| graph_error(py, e))? {
             self.cache_new_heads_py_list(&new_heads, py);
         }