From 218f0385e32499fa4fd1019199a9f4f05be8d80f Mon Sep 17 00:00:00 2001
From: Jose Gomez <jose.gomez@gateless.com>
Date: Sun, 11 Feb 2024 12:34:46 -0600
Subject: [PATCH] fix: ensure we only call clojure.core/realized? on IPending

---
 src/futurama/core.clj       | 26 ++++++++++++++++++++------
 src/futurama/protocols.clj  |  6 +++++-
 test/futurama/core_test.clj |  7 ++++---
 3 files changed, 29 insertions(+), 10 deletions(-)

diff --git a/src/futurama/core.clj b/src/futurama/core.clj
index 5234a20..dc0dc37 100644
--- a/src/futurama/core.clj
+++ b/src/futurama/core.clj
@@ -9,7 +9,7 @@
             [futurama.state :as state]
             [futurama.deferred]
             [manifold.deferred :as d])
-  (:import [clojure.lang Var IDeref IFn]
+  (:import [clojure.lang Var IDeref IPending IFn]
            [java.util.concurrent
             CompletableFuture
             CompletionException
@@ -122,6 +122,10 @@
                         res-fut#))))
 
 (extend-type Future
+  proto/AsyncPending
+  (realized? [fut]
+    (.isDone ^Future fut))
+
   proto/AsyncCancellable
   (cancel [this]
     (future-cancel this))
@@ -139,7 +143,7 @@
                              take-cb))]
       (when-let [cb (commit-handler)]
         (cond
-          (realized? fut)
+          (proto/realized? fut)
           (let [val (try
                       (.get ^Future fut)
                       (catch Throwable e
@@ -167,12 +171,18 @@
 
   impl/Channel
   (close! [fut]
-    (when-not (realized? fut)
+    (when-not (proto/realized? fut)
       (future-cancel ^Future fut)))
   (closed? [fut]
-    (realized? ^Future fut)))
+    (proto/realized? ^Future fut)))
 
 (extend-type IDeref
+  proto/AsyncPending
+  (realized? [ref]
+    (if (instance? IPending ref)
+      (realized? ref)
+      true))
+
   impl/ReadPort
   (take! [ref handler]
     (let [^IDeref ref ref
@@ -184,7 +194,7 @@
                              take-cb))]
       (when-let [cb (commit-handler)]
         (cond
-          (realized? ref)
+          (proto/realized? ref)
           (let [val (try
                       (deref ref)
                       (catch Throwable e
@@ -215,9 +225,13 @@
     (when (instance? IFn ref)
       (ref nil)))
   (closed? [ref]
-    (realized? ref)))
+    (proto/realized? ref)))
 
 (extend-type CompletableFuture
+  proto/AsyncPending
+  (realized? [fut]
+    (.isDone ^CompletableFuture fut))
+
   proto/AsyncCancellable
   (cancel [this]
     (future-cancel this))
diff --git a/src/futurama/protocols.clj b/src/futurama/protocols.clj
index af337ae..569f2ba 100644
--- a/src/futurama/protocols.clj
+++ b/src/futurama/protocols.clj
@@ -1,5 +1,9 @@
-(ns futurama.protocols)
+(ns futurama.protocols
+  (:refer-clojure :exclude [realized?]))
 
 (defprotocol AsyncCancellable
   (cancel [this])
   (cancelled? [this]))
+
+(defprotocol AsyncPending
+  (realized? [this]))
diff --git a/test/futurama/core_test.clj b/test/futurama/core_test.clj
index 04f4ff7..ab976f5 100644
--- a/test/futurama/core_test.clj
+++ b/test/futurama/core_test.clj
@@ -363,9 +363,10 @@
                           (>! c {:foo "bar"})
                           (delay
                             (future
-                              (let [p (promise)]
-                                (deliver p c)
-                                p)))))))))))))
+                              (atom
+                               (let [p (promise)]
+                                 (deliver p c)
+                                 p))))))))))))))
   (testing "nested non-blocking take - !<!"
     (<!!
      (async