notify flows: GET returns a schema of the events, fields, node kinds and limits

swarm-controller/src/forge.rs

@@ -2118,7 +2118,10 @@ mod tests {
         let mut routed = events(DeliveryKind::Issues);
         routed.extend(events(DeliveryKind::PullRequest));
         routed.sort_unstable();
-        let mut sources = swarm_wire::notify_flows::SOURCE_EVENTS.to_vec();
+        let mut sources = swarm_wire::notify_flows::SOURCE_EVENTS
+            .iter()
+            .map(|(n, _)| *n)
+            .collect::<Vec<_>>();
         sources.sort_unstable();
         assert_eq!(routed, sources);
     }

swarm-controller/src/notify_flows.rs

@@ -42,6 +42,9 @@ pub(crate) struct FlowsView {
     builtins: Vec<Flow>,
     /// The custom flows.
     flows: Vec<Flow>,
+    /// What this build accepts: source events, fields, node kinds and limits,
+    /// for an editor to offer. An older controller's answer has none.
+    schema: notify_flows::Schema,
 }
 
 /// The body of a `PUT`: the whole document.
@@ -67,6 +70,7 @@ impl FlowsView {
             disabled_builtins: doc.disabled_builtins,
             builtins: notify_flows::builtins(),
             flows: doc.flows,
+            schema: notify_flows::schema(),
         }
     }
 }
@@ -291,6 +295,10 @@ mod tests {
         assert_eq!(view.revision, 0);
         assert!(view.disabled_builtins.is_empty() && view.flows.is_empty());
         assert_eq!(view.builtins.len(), 3);
+        let json = serde_json::to_value(&view).expect("serializes");
+        assert_eq!(json["schema"]["limits"]["max_nodes"], 64);
+        assert_eq!(json["schema"]["node_kinds"][0]["kind"], "source");
+        assert_eq!(view.schema, notify_flows::schema());
 
         let Json(saved) = put_flows(
             State(state.clone()),