datalog: magic ≡ semi on federation foaf demo (237/237)

lib/datalog/scoreboard.json

@@ -1,8 +1,8 @@
 {
   "lang": "datalog",
-  "total_passed": 236,
+  "total_passed": 237,
   "total_failed": 0,
-  "total": 236,
+  "total": 237,
   "suites": [
     {"name":"tokenize","passed":26,"failed":0,"total":26},
     {"name":"parse","passed":20,"failed":0,"total":20},
@@ -13,8 +13,8 @@
     {"name":"negation","passed":10,"failed":0,"total":10},
     {"name":"aggregates","passed":20,"failed":0,"total":20},
     {"name":"api","passed":20,"failed":0,"total":20},
-    {"name":"magic","passed":28,"failed":0,"total":28},
+    {"name":"magic","passed":29,"failed":0,"total":29},
     {"name":"demo","passed":21,"failed":0,"total":21}
   ],
-  "generated": "2026-05-08T14:19:14+00:00"
+  "generated": "2026-05-08T14:29:08+00:00"
 }

lib/datalog/scoreboard.md

@@ -1,6 +1,6 @@
 # datalog scoreboard
 
-**236 / 236 passing** (0 failure(s)).
+**237 / 237 passing** (0 failure(s)).
 
 | Suite | Passed | Total | Status |
 |-------|--------|-------|--------|
@@ -13,5 +13,5 @@
 | negation | 10 | 10 | ok |
 | aggregates | 20 | 20 | ok |
 | api | 20 | 20 | ok |
-| magic | 28 | 28 | ok |
+| magic | 29 | 29 | ok |
 | demo | 21 | 21 | ok |

lib/datalog/tests/magic.sx

@@ -228,6 +228,20 @@
             (and (= (len found) 1) (= (len missing) 0))))
         true)
 
+      ;; Magic equivalence on the federation demo.
+      (dl-mt-test! "magic ≡ semi on foaf demo"
+        (let
+          ((db (dl-program-data
+                 (quote ((follows alice bob)
+                         (follows bob carol)
+                         (follows alice dave)))
+                 dl-demo-federation-rules)))
+          (let
+            ((semi (dl-query db (quote (foaf alice X))))
+              (magic (dl-magic-query db (quote (foaf alice X)))))
+            (= (len semi) (len magic))))
+        true)
+
       ;; Magic over a rule whose body contains an aggregate.
       ;; The rewriter passes aggregate body lits through unchanged
       ;; (no propagation generated for them), so semi-naive's count