push green meta builds to the attic cache and record cached

swarm-controller/src/meta_build.rs

@@ -306,13 +306,18 @@ pub(crate) async fn run(
             }
             Outcome::Failed(error_tail)
         }
-        Ok(FromMetaReply::Built { out_path, system }) => {
+        Ok(FromMetaReply::Built {
+            out_path,
+            system,
+            cached,
+        }) => {
             let built_rev = meta_rev.clone();
             let closure = AgentClosure {
                 meta_rev,
                 store_path: out_path.clone(),
                 system,
                 built_unix: unix_now(),
+                cached,
             };
             match queue.record(&agent, &closure).await {
                 Ok(()) => {
@@ -415,9 +420,14 @@ mod tests {
         }
 
         fn built() -> Self {
+            Self::built_cached(false)
+        }
+
+        fn built_cached(cached: bool) -> Self {
             Self::answering(Ok(FromMetaReply::Built {
                 out_path: "/nix/store/x-toplevel".to_owned(),
                 system: "x86_64-linux".to_owned(),
+                cached,
             }))
         }
     }
@@ -470,6 +480,22 @@ mod tests {
         assert_eq!(closure.store_path, "/nix/store/x-toplevel");
         assert_eq!(closure.system, "x86_64-linux");
         assert!(closure.built_unix > 0);
+        assert!(!closure.cached);
+    }
+
+    /// The record says what the builder said about the cache, both ways.
+    #[tokio::test]
+    async fn the_record_carries_whether_the_builder_cached_the_closure() {
+        for cached in [true, false] {
+            let queue = FakeQueue::built_cached(cached);
+            let outcome = run_with(&FakeHead::reading(Ok(Some(REV))), &queue).await;
+            assert_eq!(outcome, Outcome::Done);
+            let recorded = queue.recorded.lock().unwrap();
+            let [(_, closure)] = recorded.as_slice() else {
+                panic!("one record: {recorded:?}")
+            };
+            assert_eq!(closure.cached, cached);
+        }
     }
 
     /// Any `nix` failure, a timeout included, fails the node at once with what
@@ -749,6 +775,7 @@ mod tests {
             store_path: "/nix/store/a".to_owned(),
             system: "x86_64-linux".to_owned(),
             built_unix: 1,
+            cached: false,
         };
         client.record("atlas", &closure).await.expect("written");
         closure.store_path = "/nix/store/b".to_owned();