CLJ-1766: Serializing+deserializing lists breaks their hash

Lists declare their `hash` and `hasheq` fields as transients, which are
deserialized with default value `0`, breaking the expectation of
non-computed values. Transients are meant to be non-serialized by
default, so changing `0` to be non-computed on this case is not only
more natural but also fixes the serialization roundtrip.

Signed-off-by: Stuart Halloway <stu@cognitect.com>

src/jvm/clojure/lang/ASeq.java

@@ -14,8 +14,8 @@
 import java.util.*;
 
 public abstract class ASeq extends Obj implements ISeq, Sequential, List, Serializable, IHashEq {
-transient int _hash = -1;
-transient int _hasheq = -1;
+transient int _hash;
+transient int _hasheq;
 
 public String toString(){
 	return RT.printString(this);
@@ -62,7 +62,7 @@ public boolean equals(Object obj){
 }
 
 public int hashCode(){
-	if(_hash == -1)
+	if(_hash == 0)
 		{
 		int hash = 1;
 		for(ISeq s = seq(); s != null; s = s.next())
@@ -75,7 +75,7 @@ public int hashCode(){
 }
 
 public int hasheq(){
-	if(_hasheq == -1)
+	if(_hasheq == 0)
 		{
 //		int hash = 1;
 //		for(ISeq s = seq(); s != null; s = s.next())

test/clojure/test_clojure/serialization.clj

@@ -43,7 +43,9 @@
         rt-seq (-> v seq serialize deserialize)]
     (and (= v rt)
       (= (seq v) (seq rt))
-      (= (seq v) rt-seq))))
+      (= (seq v) rt-seq)
+      (= (hash v) (hash rt))
+      (= (.hashCode v) (.hashCode rt)))))
 
 (deftest sequable-serialization
   (are [val] (roundtrip val)