*magit-commit*.txt

commit 7d4a8f4724ea8f82709550d8a55798c87bfab802 (HEAD, refs/heads/clj-1299-no-nil)
Author: Toby Crawley <toby@tcrawley.org>
Date:   Fri Nov 22 09:49:44 2013 -0500

    Prevent a conveyed binding frame from being removed by a popThreadBindings call [CLJ-1299]
    
    This introduces a TOP frame that is used to mark the top of a
    push/pop stack. It also removes unnecessary nil checks around dvals.

	Modified   src/jvm/clojure/lang/Var.java
diff --git a/src/jvm/clojure/lang/Var.java b/src/jvm/clojure/lang/Var.java
index 7463337..af942f6 100644
--- a/src/jvm/clojure/lang/Var.java
+++ b/src/jvm/clojure/lang/Var.java
@@ -45,17 +45,13 @@ static public class Unbound extends AFn{
 }
 
 static class Frame{
+	final static Frame TOP = new Frame(PersistentHashMap.EMPTY, null);
 	//Var->TBox
 	Associative bindings;
 	//Var->val
 //	Associative frameBindings;
 	Frame prev;
 
-
-	public Frame(){
-		this(PersistentHashMap.EMPTY, null);
-	}
-
 	public Frame(Associative bindings, Frame prev){
 //		this.frameBindings = frameBindings;
 		this.bindings = bindings;
@@ -63,9 +59,7 @@ static class Frame{
 	}
 
     	protected Object clone() {
-		Frame f = new Frame();
-		f.bindings = this.bindings;
-		return f;
+		return new Frame(this.bindings, null);
     	}
 
 }
@@ -73,7 +67,7 @@ static class Frame{
 static final ThreadLocal<Frame> dvals = new ThreadLocal<Frame>(){
 
 	protected Frame initialValue(){
-		return new Frame();
+		return Frame.TOP;
 	}
 };
 
@@ -96,17 +90,11 @@ public final Namespace ns;
 //IPersistentMap _meta;
 
 public static Object getThreadBindingFrame(){
-	Frame f = dvals.get();
-	if(f != null)
-		return f;
-	return new Frame();
+	return dvals.get();
 }
 
 public static Object cloneThreadBindingFrame(){
-	Frame f = dvals.get();
-	if(f != null)
-		return f.clone();
-	return new Frame();
+	return dvals.get().clone();
 }
 
 public static void resetThreadBindingFrame(Object frame){
@@ -359,11 +347,10 @@ public static void pushThreadBindings(Associative bindings){
 }
 
 public static void popThreadBindings(){
-    Frame f = dvals.get();
-    if(f.prev == null)
+    Frame f = dvals.get().prev;
+    if (f == null) {
         throw new IllegalStateException("Pop without matching push");
-    f = f.prev;
-    if (f.prev == null) {
+    } else if (f == Frame.TOP) {
         dvals.remove();
     } else {
         dvals.set(f);
	Modified   test/clojure/test_clojure/parallel.clj
diff --git a/test/clojure/test_clojure/parallel.clj b/test/clojure/test_clojure/parallel.clj
index fb98d60..357e961 100644
--- a/test/clojure/test_clojure/parallel.clj
+++ b/test/clojure/test_clojure/parallel.clj
@@ -27,3 +27,14 @@
   ;; regression fixed in r1218; was OutOfMemoryError
   (is (= '(1) (pmap inc [0]))))
 
+
+(def ^:dynamic *test-value* 1)
+
+(deftest future-fn-properly-retains-conveyed-bindings
+  (let [a (atom [])]
+    (binding [*test-value* 2]
+      @(future (dotimes [_ 3]
+                 ;; we need some binding to trigger binding pop
+                 (binding [*print-dup* false]
+                   (swap! a conj *test-value*))))
+      (is (= [2 2 2] @a)))))

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