CLJS-2838: [spec] s/& does not check preds if regex matches empty collection

Author: mfikes

src/main/cljs/cljs/spec/alpha.cljs

@@ -1012,9 +1012,8 @@
       ::accept true
       nil nil
       ::amp (c/and (accept-nil? p1)
-                   (c/or (noret? p1 (preturn p1))
-                         (let [ret (-> (preturn p1) (and-preds ps (next forms)))]
-                           (not (invalid? ret)))))
+                   (let [ret (-> (preturn p1) (and-preds ps (next forms)))]
+                     (not (invalid? ret))))
       ::rep (c/or (identical? p1 p2) (accept-nil? p1))
       ::pcat (every? accept-nil? ps)
       ::alt (c/some accept-nil? ps))))

src/test/cljs/cljs/spec_test.cljs

@@ -126,6 +126,7 @@
         plus (s/+ keyword?)
         opt (s/? keyword?)
         andre (s/& (s/* keyword?) even-count?)
+        andre2 (s/& (s/* keyword?) #{[:a]})
         m (s/map-of keyword? string?)
         mkeys (s/map-of (s/and keyword? (s/conformer name)) any?)
         mkeys2 (s/map-of (s/and keyword? (s/conformer name)) any? :conform-keys true)
@@ -216,6 +217,10 @@
       andre [:k] ::s/invalid '[{:pred cljs.spec-test/even-count?, :val [:k]}]
       andre [:j :k] [:j :k] nil
 
+      andre2 nil ::s/invalid [{:pred #{[:a]}, :val []}]
+      andre2 [] ::s/invalid [{:pred #{[:a]}, :val []}]
+      andre2 [:a] [:a] nil
+
       m nil ::s/invalid '[{:pred cljs.core/map?, :val nil}]
       m {} {} nil
       m {:a "b"} {:a "b"} nil