Merge pull request reagent-project#373 from reagent-project/danielcompton-not=-throwing

Handle not= exception

Author: Deraen

CHANGELOG.md

@@ -10,6 +10,7 @@
 - Removed component type assertion for `:>` (#[369](https://github.com/reagent-project/reagent/issues/369), [#372](https://github.com/reagent-project/reagent/pull/372)))
   - This caused problems with React Context where component is Plain JS object with special properties
   - `React/createElement` will still provide error if `:>` is used with invalid values
+- Handle exceptions from `not=` in Reagent `component-did-update` method ([#350](https://github.com/reagent-project/reagent/pull/350), [#344](https://github.com/reagent-project/reagent/pull/344))
 
 ## 0.8.0 (2018-04-19)
 

src/reagent/impl/component.cljs

@@ -167,7 +167,10 @@
                          new-argv ($ nextprops :argv)
                          noargv (or (nil? old-argv) (nil? new-argv))]
                      (cond
-                       (nil? f) (or noargv (not= old-argv new-argv))
+                       (nil? f) (or noargv (try (not= old-argv new-argv)
+                                                (catch :default e
+                                                  (warn "Exception thrown while comparing argv's in shouldComponentUpdate: " old-argv " " new-argv " " e)
+                                                  false)))
                        noargv (.call f c c (get-argv c) (props-argv c nextprops))
                        :else  (.call f c c old-argv new-argv))))))
 

test/reagenttest/testreagent.cljs

@@ -1229,3 +1229,29 @@
                   [:> Consumer {}
                    (fn [v]
                      (r/as-element [:div "Context: " v]))]])))))
+
+(deftest on-failed-prop-comparison-in-should-update-swallow-exception-and-do-not-update-component
+  (let [prop (r/atom {:todos 1})
+        component-was-updated (atom false)
+        error-thrown-after-updating-props (atom false)
+        component-class (r/create-class {:reagent-render (fn [& args]
+                                                           [:div (str (first args))])
+                                         :component-did-update (fn [& args]
+                                                                 (reset! component-was-updated true))})
+        component (fn []
+                    [component-class @prop])]
+
+    (when (and isClient (dev?))
+      (let [e (debug/track-warnings
+                #(with-mounted-component [component]
+                   (fn [c div]
+                     (reset! prop (sorted-map 1 2))
+                     (try
+                       (r/flush)
+                       (catch :default e
+                         (reset! error-thrown-after-updating-props true)))
+
+                     (is (not @component-was-updated))
+                     (is (not @error-thrown-after-updating-props)))))]
+        (is (re-find #"Warning: Exception thrown while comparing argv's in shouldComponentUpdate:"
+                     (first (:warn e))))))))