From 54ecf706d50733b31bcb452495ae991e913e2e24 Mon Sep 17 00:00:00 2001
From: Dan Holmsand <holmsand@gmail.com>
Date: Wed, 14 Oct 2015 15:08:33 +0200
Subject: [PATCH] Rethrow errors caught during try-run

---
 src/reagent/ratom.cljs | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/src/reagent/ratom.cljs b/src/reagent/ratom.cljs
index 4c1e5bd..72658b3 100644
--- a/src/reagent/ratom.cljs
+++ b/src/reagent/ratom.cljs
@@ -335,7 +335,8 @@
 
 
 (deftype Reaction [f ^:mutable state ^:mutable ^boolean dirty? ^boolean nocache?
-                   ^:mutable watching ^:mutable watches ^:mutable auto-run]
+                   ^:mutable watching ^:mutable watches ^:mutable auto-run
+                   ^:mutable caught]
   IAtom
   IReactiveAtom
 
@@ -394,9 +395,8 @@
       (try
         (._run this)
         (catch :default e
-          ;; Just log error: it will most likely pop up again at deref time.
-          (error "Error in reaction:" e)
           (set! state nil)
+          (set! caught e)
           (notify-w this e nil)))))
 
   (_run [this]
@@ -428,6 +428,9 @@
 
   IDeref
   (-deref [this]
+    (when-some [e caught]
+      (set! caught nil)
+      (throw e))
     (let [non-reactive (nil? *ratom-context*)]
       (when non-reactive
         (flush!))
@@ -467,7 +470,7 @@
 
 
 (defn make-reaction [f & {:keys [auto-run on-set on-dispose]}]
-  (let [reaction (Reaction. f nil true false nil nil nil)]
+  (let [reaction (Reaction. f nil true false nil nil nil nil)]
     (._set-opts reaction {:auto-run auto-run
                           :on-set on-set
                           :on-dispose on-dispose})