Remove cached hashcode from MutableExpr

PiperOrigin-RevId: 623887941

Author: l46kok

common/src/main/java/dev/cel/common/ast/CelMutableExpr.java

@@ -39,7 +39,6 @@ public final class CelMutableExpr {
   private long id;
   private ExprKind.Kind exprKind;
   private Object exprValue;
-  private int hash = 0;
 
   public long id() {
     return id;
@@ -1016,19 +1015,12 @@ public boolean equals(Object obj) {
 
   @Override
   public int hashCode() {
-    if (hash == 0) {
-      int h = 1;
-      h *= 1000003;
-      h ^= (int) ((id >>> 32) ^ id);
-      h *= 1000003;
-      h ^= this.exprValue().hashCode();
-
-      if (h == 0) {
-        h = 1;
-      }
-      hash = h;
-    }
+    int h = 1;
+    h *= 1000003;
+    h ^= (int) ((id >>> 32) ^ id);
+    h *= 1000003;
+    h ^= this.exprValue().hashCode();
 
-    return hash;
+    return h;
   }
 }

common/src/test/java/dev/cel/common/ast/CelMutableExprTest.java

@@ -783,4 +783,14 @@ public void hashCodeTest(@TestParameter HashCodeTestCase testCase) {
     // Run it twice to ensure cached value is stable
     assertThat(testCase.mutableExpr.hashCode()).isEqualTo(testCase.expectedHashCode);
   }
+
+  @Test
+  public void propertyMutated_hashCodeChanged() {
+    CelMutableExpr mutableExpr = CelMutableExpr.ofIdent("x");
+    int originalHash = mutableExpr.hashCode();
+
+    mutableExpr.ident().setName("y");
+
+    assertThat(originalHash).isNotEqualTo(mutableExpr.hashCode());
+  }
 }