fix(QA-018): prohibir múltiples wires al mismo puerto de entrada

src/graph/model.red

@@ -412,6 +412,42 @@ find-node-by-id: func [nodes id /local node] [
     none
 ]
 
+; ══════════════════════════════════════════════════
+; WIRE GUARD — previene múltiples wires al mismo puerto entrada (QA-018)
+; ══════════════════════════════════════════════════
+; Regla absoluta #6: NUNCA permitir múltiples wires a un puerto de entrada.
+; Esta función verifica si ya existe un wire conectado al mismo nodo+puerto destino.
+; Devuelve true si EL wire YA EXISTE (para no añadirlo de nuevo).
+wire-exists-to-port?: func [
+    "Comprueba si ya existe un wire conectado al mismo puerto de entrada"
+    wires     [block!]   "Lista de wires a comprobar (model/wires o st/wires)"
+    to-id     [integer!] "ID del nodo destino"
+    to-port   [word!]    "Nombre del puerto de entrada"
+    /local w
+][
+    foreach w wires [
+        if all [
+            (w/to-node = to-id)
+            (w/to-port = to-port)
+        ] [
+            return true
+        ]
+    ]
+    false
+]
+
+; Añade un wire a una lista solo si el puerto destino no tiene ya uno (QA-018).
+; Usar en lugar de `append wires make-wire [...]` en canvas.red y tests.
+add-wire: func [
+    "Añade wire a la lista si el puerto destino aún no tiene uno (regla #6)"
+    wires  [block!]  "Lista de wires destino (model/wires o st/wires)"
+    wire   [object!] "Wire creado con make-wire"
+][
+    unless wire-exists-to-port? wires wire/to-node wire/to-port [
+        append wires wire
+    ]
+]
+
 ; make-fp-item y fp-value-text viven en src/ui/panel/panel.red (canónico).
 ; model.red no duplica lógica de Front Panel.
 

src/ui/diagram/canvas.red

@@ -1891,7 +1891,7 @@ render-diagram: func [model canvas-width canvas-height /local canvas-face] [
                                             actual-from-node: model/wire-src-struct/id
                                         ]
                                     ]
-                                    append wire-list make-wire compose [
+                                    add-wire wire-list make-wire compose [
                                         from: (actual-from-node)
                                         from-port: (actual-from-port)
                                         to: (hit-nd/id)
@@ -1953,7 +1953,7 @@ render-diagram: func [model canvas-width canvas-height /local canvas-face] [
                                     _out-t: port-out-type model/wire-src model/wire-port
                                     either _out-t = _sr/data-type [
                                         model/broken-wire: none
-                                        append model/wires make-wire compose [
+                                        add-wire model/wires make-wire compose [
                                             from: (model/wire-src/id)  from-port: (model/wire-port)
                                             to: (_st/id)  to-port: (to-word _sr/name)
                                         ]
@@ -1973,7 +1973,7 @@ render-diagram: func [model canvas-width canvas-height /local canvas-face] [
                                     _out-t: port-out-type model/wire-src model/wire-port
                                     either _out-t = _sr/data-type [
                                         model/broken-wire: none
-                                        append _st/wires make-wire compose [
+                                        add-wire _st/wires make-wire compose [
                                             from: (model/wire-src/id)  from-port: (model/wire-port)
                                             to: -2  to-port: (to-word _sr/name)
                                         ]
@@ -2158,7 +2158,7 @@ render-diagram: func [model canvas-width canvas-height /local canvas-face] [
                                 remove-each _w model/wires [
                                     all [_w/to-node = _fst/id  _w/to-port = 'count]
                                 ]
-                                append model/wires make-wire compose [
+                                add-wire model/wires make-wire compose [
                                     from: (model/wire-src/id)  from-port: (model/wire-port)
                                     to: (_fst/id)  to-port: "count"
                                 ]
@@ -2347,7 +2347,7 @@ render-diagram: func [model canvas-width canvas-height /local canvas-face] [
                                     actual-from-node: model/wire-src-struct/id
                                 ]
                             ]
-                            append wire-list make-wire compose [
+                            add-wire wire-list make-wire compose [
                                 from: (actual-from-node)
                                 from-port: (actual-from-port)
                                 to: (hit-result/1/id)

tests/test-model.red

@@ -298,4 +298,45 @@ assert "bundle gen-name bundle_1"    (nb1/name = "bundle_1")
 assert "bundle gen-name bundle_2"    (nb2/name = "bundle_2")
 assert "unbundle gen-name unbundle_1" (nu1/name = "unbundle_1")
 
+; ── QA-018 — prohibir múltiples wires al mismo puerto de entrada ─────────
+
+reset-name-counters
+
+; Crear un diagrama con nodos con IDs manuales (make-diagram no tiene next-id)
+demo-model: make-diagram "demo"
+
+n1: make-node compose [id: (1)  type: 'add  x: 100  y: 100]
+n2: make-node compose [id: (2)  type: 'add  x: 250  y: 100]
+n3: make-node compose [id: (3)  type: 'add  x: 400  y: 100]
+n4: make-node compose [id: (4)  type: 'add  x: 550  y: 100]
+
+append demo-model/nodes n1
+append demo-model/nodes n2
+append demo-model/nodes n3
+append demo-model/nodes n4
+
+; Crear 2 wires al mismo puerto de entrada (to-port = 'a)
+; El segundo no debe ser añadido (regla absoluta #6 — add-wire lo rechaza)
+add-wire demo-model/wires make-wire compose [
+    from: (1)  from-port: 'result  to: (2)  to-port: 'a
+]
+add-wire demo-model/wires make-wire compose [
+    from: (3)  from-port: 'result  to: (2)  to-port: 'a
+]
+
+assert "QA-018: solo 1 wire al mismo puerto" (1 = length? demo-model/wires)
+assert "QA-018: el primer wire se mantiene"  (1 = demo-model/wires/1/from-node)
+
+; Crear 2 wires a puertos distintos del mismo nodo → ambos deben añadirse
+add-wire demo-model/wires make-wire compose [
+    from: (1)  from-port: 'result  to: (4)  to-port: 'a
+]
+add-wire demo-model/wires make-wire compose [
+    from: (2)  from-port: 'result  to: (4)  to-port: 'b
+]
+
+assert "QA-018: 3 wires en total"         (3 = length? demo-model/wires)
+assert "QA-018: primer wire a puerto 'a"  (1 = demo-model/wires/2/from-node)
+assert "QA-018: segundo wire a puerto 'b" (2 = demo-model/wires/3/from-node)
+
 print "--- tests finalizados ---"