From 2284b7a8858e82873fa0c76be61967366bbcbf6c Mon Sep 17 00:00:00 2001
From: Jacob Finkelman <jfinkelm@amazon.com>
Date: Tue, 19 Sep 2023 20:22:13 +0000
Subject: [PATCH] added assertions to make sure the path code is correct in
 graphs

---
 src/cargo/util/graph.rs | 27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)

diff --git a/src/cargo/util/graph.rs b/src/cargo/util/graph.rs
index ff4018201..b3214ee86 100644
--- a/src/cargo/util/graph.rs
+++ b/src/cargo/util/graph.rs
@@ -106,6 +106,18 @@ impl<N: Eq + Ord + Clone, E: Default + Clone> Graph<N, E> {
             result.push(p);
             pkg = p.0;
         }
+        #[cfg(debug_assertions)]
+        {
+            for x in result.windows(2) {
+                let [(n1, _), (n2, Some(e12))] = x else {
+                    unreachable!()
+                };
+                assert!(std::ptr::eq(self.edge(n1, n2).unwrap(), *e12));
+            }
+            let last = result.last().unwrap().0;
+            // fixme: this may be wrong when there are cycles, but we dont have them in tests.
+            assert!(!self.nodes.contains_key(last));
+        }
         result
     }
 
@@ -134,6 +146,21 @@ impl<N: Eq + Ord + Clone, E: Default + Clone> Graph<N, E> {
             result.push(p);
             pkg = p.0;
         }
+        #[cfg(debug_assertions)]
+        {
+            for x in result.windows(2) {
+                let [(n2, _), (n1, Some(e12))] = x else {
+                    unreachable!()
+                };
+                assert!(std::ptr::eq(self.edge(n1, n2).unwrap(), *e12));
+            }
+            let last = result.last().unwrap().0;
+            // fixme: this may be wrong when there are cycles, but we dont have them in tests.
+            assert!(!self
+                .nodes
+                .iter()
+                .any(|(_, adjacent)| adjacent.contains_key(last)));
+        }
         result
     }
 }