From 30e029aad0f13c33a2684b257bdea8d469ceb49e Mon Sep 17 00:00:00 2001
From: Kimo Knowles <kimo.knowles@day8.com.au>
Date: Wed, 26 Jun 2024 14:28:16 +0200
Subject: [PATCH] Calculate flow interceptors earlier than user interceptors

---
 docs/releases/2024.md        | 12 ++++++++++++
 src/re_frame/alpha.cljc      | 12 ++++++------
 src/re_frame/flow/alpha.cljc | 12 +++++++-----
 3 files changed, 25 insertions(+), 11 deletions(-)

diff --git a/docs/releases/2024.md b/docs/releases/2024.md
index 7005d9e4..c00ac780 100644
--- a/docs/releases/2024.md
+++ b/docs/releases/2024.md
@@ -6,6 +6,18 @@
 
 > The re-frame [Clojars page](https://clojars.org/re-frame/) contains dependency coordinates for Maven/deps/Lein.
 
+## 1.4.4 (2024-06-24)
+
+#### Changed
+
+    - Changed flows to calculate the new app-db earlier in the chain.
+      - Benefit:  user-defined interceptors can access post-flow app-db value.
+      - Drawback: they can't access the value of app-db directly resulting from the event handler.
+      - Drawback: they can't access flow-related effects like `:reg-flow`.
+
+    - Added a :re-frame/pre-flow-db key to the context
+      - This way, user-defined interceptors can still access the app-db value resulting directly from the event handler.
+
 ## 1.4.3 (2024-01-25)
 
 #### Fixed
diff --git a/src/re_frame/alpha.cljc b/src/re_frame/alpha.cljc
index b16a1168..23416645 100644
--- a/src/re_frame/alpha.cljc
+++ b/src/re_frame/alpha.cljc
@@ -423,10 +423,10 @@
   ([id interceptors handler]
    (events/register id [cofx/inject-db
                         fx/do-fx
-                        flow/interceptor
-                        flow/do-fx
                         std-interceptors/inject-global-interceptors
                         interceptors
+                        flow/interceptor
+                        flow/do-fx
                         (db-handler->interceptor handler)])))
 
 (defn reg-event-fx
@@ -463,10 +463,10 @@
   ([id interceptors handler]
    (events/register id [cofx/inject-db
                         fx/do-fx
-                        flow/interceptor
-                        flow/do-fx
                         std-interceptors/inject-global-interceptors
                         interceptors
+                        flow/interceptor
+                        flow/do-fx
                         (fx-handler->interceptor handler)])))
 
 (defn reg-event-ctx
@@ -500,10 +500,10 @@
   ([id interceptors handler]
    (events/register id [cofx/inject-db
                         fx/do-fx
-                        flow/interceptor
-                        flow/do-fx
                         std-interceptors/inject-global-interceptors
                         interceptors
+                        flow/interceptor
+                        flow/do-fx
                         (ctx-handler->interceptor handler)])))
 
 (defn clear-event
diff --git a/src/re_frame/flow/alpha.cljc b/src/re_frame/flow/alpha.cljc
index 2f704fdd..dffdf995 100644
--- a/src/re_frame/flow/alpha.cljc
+++ b/src/re_frame/flow/alpha.cljc
@@ -165,8 +165,10 @@
 
 (def interceptor
   (->interceptor
-   {:id :flow
-    :after (fn [ctx]
-             (let [all-flows (with-cleared @flows)]
-               (swap! flows vary-meta dissoc ::cleared)
-               (reduce run ctx ((memoize topsort) all-flows))))}))
+   {:id    :flow
+    :after (comp (fn [ctx]
+                   (let [all-flows (with-cleared @flows)]
+                     (swap! flows vary-meta dissoc ::cleared)
+                     (reduce run ctx ((memoize topsort) all-flows))))
+                 (fn [{{:keys [db]} :effects :as ctx}]
+                   (assoc ctx :re-frame/pre-flow-db db)))}))