Fix #399, fix React key check with :> shortcut

CHANGELOG.md

@@ -5,6 +5,7 @@
 - Fixed merge-props adding `:class` property to result even if no argument
 defined `:class` ([#479](https://github.com/reagent-project/reagent/pull/479))
 - Fix using `:className` property together with keyword class shortcut ([#433](https://github.com/reagent-project/reagent/issues/433))
+- Fix incorrect missing React key warnings with `:>` ([#399](https://github.com/reagent-project/reagent/issues/399))
 
 ## 0.10.0 (2020-03-06)
 

src/reagent/impl/template.cljs

@@ -287,7 +287,11 @@
 (defn key-from-vec [v]
   (if-some [k (-> (meta v) get-key)]
     k
-    (-> v (nth 1 nil) get-key)))
+    (or (-> v (nth 1 nil) get-key)
+        ;; :> is a special case because properties map is the first
+        ;; element of the vector.
+        (if (= :> (nth v 0 nil))
+          (get-key (nth v 2 nil))))))
 
 (defn reag-element [tag v]
   (let [c (comp/as-class tag)

test/reagent/impl/template_test.cljs

@@ -22,3 +22,8 @@
                  (tmpl/convert-props {:class "a"} (tmpl/HiccupTag. nil nil nil true))))
   (is (js-equal? #js {:className "a b" :id "a"}
                  (tmpl/convert-props {:class "b"} (tmpl/HiccupTag. nil "a" "a" false)))))
+
+(deftest key-from-vec-test
+  (is (= 1 (tmpl/key-from-vec ^{:key 1} [:foo "bar"])))
+  (is (= 1 (tmpl/key-from-vec [:foo {:key 1} "bar"])))
+  (is (= 1 (tmpl/key-from-vec [:> "div" {:key 1} "bar"]))))

test/reagenttest/testreagent.cljs

@@ -523,6 +523,14 @@
     (is (= (rstr [:div "a" "b" [:div "c"]])
            (rstr [:> d2 "a" "b" [:div "c"]])))))
 
+(deftest adapt-react-class-shortcut-key-warning
+  (let [w (debug/track-warnings
+           #(with-mounted-component [:div
+                                     (list
+                                      [:> "div" {:key 1} "a"]
+                                      [:> "div" {:key 2} "b"])]
+              (fn [c div])))]
+      (is (empty? (:warn w)))))
 
 (deftest test-reactize-component
   (let [ae r/as-element